Reuse and Salvage of New Scroll Fuel Systems (NSFS) for 3200, 3300, & 3400 Engines {1250, 1256} Caterpillar

Caterpillar Products

All 3200 Engines

All 3300 Engines

All 3400 Engines

Introduction

Table 1

Revision	Summary of Changes in SEBF8327
10	Added serial numbers
09	Combined and SIS authored information from SEBF8293, SEBF8294, SEBF8296, SEBF8297, SEBF8298, SEBF8299, SEBF8300, SEBF8340, SEBF8344, SEBF8346, SEBF8348, and added 168 illustrations.
08	Added serial numbers
07	Added serial numbers

© 2019 Caterpillar® All Rights Reserved. This guideline is for the use of Cat dealers only. Unauthorized use of this document or the proprietary processes therein without permission may be violation of intellectual property law.

Information contained in this document is considered Caterpillar: Confidential Yellow.

This Reuse and Salvage Guideline contains the necessary information to allow a dealer to establish a parts reusability program. Reuse and salvage information enables Caterpillar dealers and customers to benefit from cost reductions. Every effort has been made to provide the most current information that is known to Caterpillar. Continuing improvement and advancement of product design might have caused changes to your product which are not included in this publication. This Reuse and Salvage Guideline must be used with the latest technical information that is available from Caterpillar.

For technical questions when using this document, work with your Dealer Technical Communicator (TC).

To report suspected errors, inaccuracies, or suggestions regarding the document, submit a form for feedback in the Service Information System (SIS Web) interface.

Canceled Part Numbers and Replaced Part Numbers

This document may not include canceled part numbers and replaced part numbers. Use NPR on SIS for information about canceled part numbers and replaced part numbers. NPR will provide the current part numbers for replaced parts.

Important Safety Information

Illustration 1	g02139237

Work safely. Most accidents that involve product operation, maintenance, and repair are caused by failure to observe basic safety rules or precautions. An accident can often be avoided by recognizing potentially hazardous situations before an accident occurs. A person must be alert to potential hazards. This person should also have the necessary training, skills, and tools to perform these functions properly. Safety precautions and warnings are provided in this instruction and on the product. If these hazard warnings are not heeded, bodily injury or death could occur to you or to other persons. Caterpillar cannot anticipate every possible circumstance that might involve a potential hazard. Therefore, the warnings in this publication and the warnings that are on the product are not all inclusive. If a tool, a procedure, or operating technique is not recommended by Caterpillar, ensure that it is safe for you and for other people. Ensure that the product will not be damaged or the product will not be made unsafe by the operation, lubrication, maintenance, or the repair procedures that are used.

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Improper operation, lubrication, maintenance or repair of this product can be dangerous and could result in injury or death. Do not operate or perform any lubrication, maintenance or repair on this product, until you have read and understood the operation, lubrication, maintenance and repair information.

Safety precautions and warnings are provided in this manual and on the product. If these hazard warnings are not heeded, bodily injury or death could occur to you or to other persons.

The hazards are identified by the safety alert symbol which is followed by a signal word such as danger, warning, or caution. The "WARNING" safety alert symbol is shown below.

Illustration 2	g00008666

This safety alert symbol means:

Pay attention!

Become alert!

Your safety is involved.

The message that appears under the safety alert symbol explains the hazard.

Operations that may cause product damage are identified by "NOTICE" labels on the product and in this publication.

Caterpillar cannot anticipate every possible circumstance that might involve a potential hazard. The safety information in this document and the safety information on the machine are not all inclusive. Determine that the tools, procedures, work methods, and operating techniques are safe. Determine that the operation, lubrication, maintenance, and repair procedures will not damage the machine. Also, you must determine that the operation, lubrication, maintenance, and repair procedures will not make the machine unsafe.

The information, the specifications, and the illustrations that exist in this guideline are based on information which was available at the time of publication. The specifications, torques, pressures, measurements, adjustments, illustrations, and other items can change at any time. These changes can affect the service that is given to the product. Obtain the complete, most current information before you start any job. Caterpillar dealers can supply the most current information.

Summary

To diagnose and troubleshoot engine performance problems related to the low-pressure fuel system, a series of simple steps will allow maintenance personnel to check for air in the fuel, flow restrictions, fuel transfer pump efficiency, and pressure. Any problems in the low-pressure supply system can then be isolated, corrected, and the system retested.

The FT-1996 Low-Pressure Tank Kit, test procedure, and troubleshooting flow chart will allow testing of the complete low-pressure fuel supply system without loading the engine or disconnecting any lines or fittings. The test is accomplished with a fabricated test kit which is installed between the secondary fuel filter base and the fuel filter.

During this test, the fuel supply is routed through a separate modified filter base which has fuel pressure and fuel temperature instrumentation, air sight glass, orifice, and fuel bypass valve.

The test kit can also be used during a dynamometer test. The quick disconnect fittings allow easy installation of a fuel flow meter in series with the test kit.

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NOTICE
If a fuel meter is used with the test kit, use only a displacement-type meter. Do not use a scale-type meter that first weighs the fuel and then calculates fuel flow.

The engine is operated at rated speed with no load for the low-pressure fuel system test. At rated speed the bypass valve is opened and fuel is rerouted through the orifice back to the fuel tank. The orifice allows a flow of fuel that approximates the amount of fuel the engine uses under full load. The normal fuel return line will also continue to return approximately 34.0 L per hour (8.98 US gal per hour). The combination of the two fuel flows will simulate the low-pressure fuel supply system operation as if under full load conditions. The fuel pressure, fuel temperature, and sight glass can then be observed for proper pressure, temperature, and acceptable air.

On some Caterpillar engines, measuring return fuel flow in an accurate manner may be difficult because of air bubbles in the return fuel. The air bubbles in the fuel cause the turbine flowmeter to read higher fuel flow rates than actual.

Caterpillar recommends installing a 138.00 kPa (20.016 psi) check valve at the outlet of flowmeter that is reading return fuel flow. The check valve will prevent any air bubbles in the return flow from expanding while the fuel is flowing through the flowmeter. The result is a more accurate reading of return fuel flow. Refer to "Installing a Check Valve" for installation requirements.

Service Letters and Technical Information Bulletins

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NOTICE
The most recent Service Letters and Technical Information Bulletins that are related to this component shall be reviewed before beginning work. Often Service Letters and Technical Information Bulletins contain upgrades in repair procedures, parts, and safety information that pertain to the parts or components being repaired.

References

Table 2

References
Media Number	Title
SEHS7931	Special Instruction, "Using The 6V-4060 Engine Set Point Indicator Group"
SEHS8024	Special Instruction, "Use of 6V-6070 Governor Adjusting Tool Group"
SEHS8463	Special Instruction, "Fuel System and Fuel Ratio Control Test Procedure"
SEHS9414	Special Instruction, "Fuel Transfer Pump Seal and Spacer Replacement"
SEHS9655	Special Instruction, "Installation of High-Level Fuel Tank Vent and Modification of Fuel Tank Caps for Challenger Tractors"
SEHS9980	Special Instruction, "Assembly Procedure For The 793C Off-Highway Truck"
SEHS8874	Tool Operating Manual, "Using the Caterpillar Fuel Flow Monitor System"
SEBF8347	General Service Information, "Fuel and Fuel System Related Problems"
SEBF2120	Reuse and Salvage Guidelines, "Thermal Spray Procedures for Engine Cylinder Block Top Surface"
SEBF9238	Reuse and Salvage Guidelines, "Fundamentals of Arc Spray for Reconditioning Components"
SEBF9240	Reuse and Salvage Guidelines, "Fundamentals of Flame Spray for Reconditioning Components"
SEHS8869	Special Instruction, "Cylinder Block Salvage Procedure Using Belzona Ceramic R Metal"
SENR6521	Troubleshooting, "3406C Truck Engine"
SENR6522	Troubleshooting, "3306C Diesel Truck Engine"

Tooling and Equipment

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NOTICE
Failure to follow the recommended procedure or the specified tooling that is required for the procedure could result in damage to components. To avoid component damage, follow the recommended procedure using the recommended tools.

Table 3

Required Tooling and Equipment
Part Number	Description	Qty
1U-9366	Automatic Tape Measure	1
1U-9915	Curved Handle Wire Brush	1
4C-4804	Penetrant	As needed
4C-9442	Flashlight	As needed
4S-9405	Caliper	1
5P-3920	Steel Ruler	1
5P-7414	Seal Pick	1
6V-2010	Polishing Stone	1
8H-8581	Feeler Gauge	As needed
8S-2257	Eye Loupe	As needed
8T-5096	Dial Indicator Group	1
8T-7765	Surface Reconditioning Pad	As needed
9A-1593	Comparison Gauge	As needed
9S-8903	Indicator Contact Point	1
9U-6182	Inspection Mirror	1
237-5181	Respirator	As needed
254-5319	Surface Condition Brush	As needed
262-8390	Microscope, Pocket 40x	As needed
263-7184	Crack Detection Kit	1
288-4209	Paper Towel	As needed
367-9109	Digital Caliper	1
385-8484	Level 305 mm (12 inch)	As needed
385-4008	Micrometer Tool Set, External 1524 mm (60 inch)	1
385-9422	Micrometer Extensions, Internal 50 - 609 mm (2 - 24 inch)	1
386-3364	Straight Edge	As needed
415-4055	Ultrasonic Tool Group	As needed
420-5317	Tool Cribbing	As needed
423-4373	Digital Caliper 0.0 - 203.2 mm (0.00 - 8.00 inch)	As needed
431-4150	Micrometer, External 25 mm (1 inch)	1
459-0184	UV Lamp Group	As needed
473-8688 or 473-8689	Micrometer, Inside 2.00 - 12.00 inch	1
	Micrometer, Inside 50 - 300 mm	1
473-8690	Micrometer, Outside 0.00 - 4.00 inch	1
473-8691	Micrometer, Outside 2.00 - 6.00 inch	1
473-8691	Micrometer, Outside 50.8 - 152.4 mm (2.00 - 6.00 inch)	As needed
473-8692	Micrometer, Outside 152.4 - 304.8 mm (6.00 - 12.00 inch)	As needed
474-3709 or 474-3710	Micrometer, Inside (8.00 - 32.00 inch)	As needed
	Micrometer, Inside 200 - 800 mm	As needed

Replacement Parts

Consult the applicable Parts Identification manual for your engine.

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When replacement parts are required for this product Caterpillar recommends using Caterpillar replacement parts or parts with equivalent specifications including, but not limited to, physical dimensions, type, strength and material. Failure to heed this warning can lead to premature failures, product damage, personal injury or death.

Standardized Parts Marking Procedure

Reference: SEBF8187Reuse and Salvage Guidelines, "Standardized Parts Marking Procedures".

The code is a Cat standard and is used to record the history of a component. The code will identify the number of rebuilds and hours at the time of each rebuild. This information is important and should be considered for any decision to reuse a component.

Ensure that the mark is not covered by a mating part. Use a metal marking pen to mark the code onto the component.

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NOTICE
Do not use numbering stamp punches to mark internal components. The impact from striking the stamp will cause an abnormal stress riser. The added stress riser may cause premature part failure.

Illustration 3	g06124077
DO NOT use numbering stamp punches to mark internal components.

The procedure for marking components is a Cat standard. This code is helpful when the machine is sold into a different territory after the first rebuild. During an overhaul, the previous code of a part should never be removed.

Example 1

Illustration 4	g03856853
Typical Example

Illustration 4 shows code (1-15). The first number (1) indicates that the gear had been rebuilt once. The second number (15) indicates that there were 15,000 hours on the gear at the time of rebuild.

Example 2

Illustration 5	g03856857
Typical Example

Illustration 5 shows code (1-12) and code (2-10). Code (2-10) represents the information from the second rebuild. The first number (2) indicates that the gear had been rebuilt twice. The second number (10) indicates that 10,000 hours accumulated on the gear between the first and second rebuild.

Note: Add the first and second rebuild hours to obtain the total number of hours for the gear in Illustration 5. In this example, the gear has a total of 22,000 hours.

Measurement Requirements

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NOTICE
Precise measurements shall be made when the component and measurement equipment are at 20° (68° F). Measurements shall be made after both the component and measurement equipment have had sufficient time to soak at 20° (68° F). This will ensure that both the surface and core of the material is at the same temperature.

Troubleshooting

Misfire

(Rough running, missing, skipping, fuel knock, hunt, surge, or flutter)

1. Is misfire present (check all the areas that apply):

   _____ Under load?

   _____ With no load (free running)?

   _____ At low idle?

   _____ At high idle?

   _____ Only when engine is warm?

   Description of problem:

   ________________________________

   ________________________________

   ________________________________

   ________________________________

2. List any recent repairs or modifications that could affect the current problem.

   ________________________________

   ________________________________

   ________________________________

   ________________________________

3. Has the misfire problem:

   _____ Developed gradually?

   _____ Developed suddenly?

   _____ Been present since purchase?

Low Power

(Slow Response, Poor Acceleration, Will not Pull Load, Track Stall, and Bucket Stall)

1. Is low power experienced.

   _____ Under load?

   _____ Only during acceleration or load change (poor response)?

   Description of problem:

   ________________________________

   ________________________________

   ________________________________

   ________________________________

2. Is too much exhaust smoke seen in addition to low power?

   _____ No

   _____ Yes

   _____ If yes, black smoke?

   _____ If yes, white smoke?

3. List any recent repairs or modifications that could affect the current problem.

   ________________________________

   ________________________________

   ________________________________

   ________________________________

4. Has the low-power problem:

   _____ Developed gradually?

   _____ Developed suddenly?

   _____ Been present since purchase?

Hard to Start or Will Not Start

1. Is engine hard to start (check all the areas that apply):

   _____ After the engine has been shut down less than 30 minutes?

   _____ After the engine has been shut down for 30 minutes or more?

   _____ All the time?

   _____ Only in cold ambient temperatures?

   Description of problem:

   ________________________________

   ________________________________

   ________________________________

   ________________________________

2. List any recent repairs or modifications that could affect the current problem.

3. Has the hard starting problem:

   _____ Developed gradually?

   _____ Developed suddenly?

   _____ Been present since purchase?

Internal Leaks (Fuel in Engine Oil)

For additional information, refer to "Test F".

1. Has the amount of fuel in the oil been measured?

   _____ No

   _____ Yes

   _____ If yes, what %?

   _____ In miles?

   _____ Hours?

2. List any recent repairs or modifications that could affect the current problem.

   ________________________________

   ________________________________

   ________________________________

   ________________________________

3. Has the oil dilution problem:

   _____ Developed gradually?

   _____ Developed suddenly?

   _____ Been present since purchase?

External Leaks

For additional information, refer to "Test F".

1. Is leak present (check all the areas that apply):

   _____ Under load?

   _____ Fuel?

   _____ Engine Oil?

   _____ All the time?

   _____ Only when warm?

   Description of problem:

   ________________________________

   ________________________________

   ________________________________

   ________________________________

2. List any recent repairs or modifications that could affect the current problem.

   ________________________________

   ________________________________

   ________________________________

   ________________________________

3. Has the leak problem:

   _____ Developed gradually?

   _____ Developed suddenly?

   _____ Been present since purchase?

Flow Charts

Misfire (Rough running, missing, skipping, fuel knock, hunt, surge, or flutter)

Illustration 6	g06334507

Low Power

Illustration 7	g06334511

Illustration 8	g06334513

Hard to Start or Will Not Start

Illustration 9	g06334518

Fuel System Diagnostic Tests

The following tests should be used with the flow charts to help determine fuel system problems.

Always review the flow charts before doing any of the tests within the test procedures.

Table 4

Fuel System Diagnostic
Test	Description
A	Governor Linkage Binding and Misadjustment This test checks for binding in the governor and control linkage.
B	Low-Pressure Fuel Supply System This test verifies the low-pressure system is working properly.
C	NSFS Misfire This test helps with identifying a cylinder misfire problem.
D	Governor InstabilityThis test checks for misfire and surge due to governor instability.
E	Fuel Quality This test checks for fuel quality problems.
F	Injection Pump Cranking This test checks for worn fuel injection pumps by measuring cranking rack.
G	Plugged Nozzle Orifice and Pop Test This test checks for proper fuel nozzle functions.
H	Fuel Shutoff Solenoid This test determines if the fuel shutoff solenoid and wiring harness are operating properly.
I	Fuel Ratio Control Setting This test checks the air-to-fuel ratio control setting (FRC).
J	Fuel Transfer Pump (Incorrect Pressure) This test is a visual inspection of fuel transfer pump components.
K	Fuel Ratio Control Diaphragm Leak This test checks for a leakage FRC diaphragm.

Governor Linkage Binding and Adjustment, Test A

Illustration 10	g06334705
This test checks for binding in the governor and control linkage.

Low-Pressure Fuel System Test, Test B

Illustration 11	g02576359

Table 5

FT-1996 Low-Pressure Fuel System Test Kit
Item	Qty	Part No.	Description
1	1	9N-1851	Bracket
2	1	1W-3892	Base Assembly, Fuel Filter
	2	OS-1588(1)	Bolt
	2	1D-4717(1)	Nut
	4	5M-2894(1)	Washer
3	1	6N-4414	Cover
4	1	1P-0436	Gasket
5	1	1B-7182	Bolt
	1	7B-2742	Bolt
6	1	9M-1974	Washer
	1	5P-0537	Washer
7	2	5P-3501	Adapter
8	3	3J-1907	Seal
9	1	3B-7738	Nipple
10	2	3B-7722	Bushing
11	1	377-5782	Sight Gauge
12	1	9L-0945	U-Bolt
13	2	1B-4330	Nuts
14	2	5P-0537	Washer
15	2	3B-6553	Elbow
	2	8B-6021	Adapter
16	2	3L-6578	Hose Assembly
17	2	3P-2232	Coupler Assembly
18	2	3P-2234	Nipple
19	1	8T-0935	Thermocouple Assembly
20	1	2P-2288	Adapter
21	1	6F-8146	Seal
22	1	4J-5267	Seal
23	1	1L-2279	Elbow
24	1	3B-7741	Nipple
25	1	1L-1644	Nipple
26	1	6N-1716(2)	Bypass Valve Assembly
27	1	5P-9617	Adapter
28	1	--	Steel or Copper Tubing ( 6.35 mm (0.250)in O.D.) 32.0 mm (1.26)in long
29	1	9M-9677(3)	Connector
30	1	2P-4439(4)	Adapter 1.57 mm (0.062 in)
31	1	5P-4405	Connector
32	--	5P-6011	Tube, 3.6 m (11.81 ft)
33	1	9L-8493(5)	Cap
--	1	8T-0841(6)	Case (storage)

(1)	Used to attach 1W-3892 Base Assembly to 9N-1851 Bracket.
(2)	Remove constant purge valve, spring, and adjustment screw before installing.
(3)	May be substituted with 5P-4400 Connector and 3B-6768 Bushing.
(4)	This orifice size for 3300, 3406B, and 3406C NSFS engines only.
(5)	Cap must be replaced with appropriate fittings for checking fuel supply pressure.
(6)	Case optional.

Illustration 12	g02582824

Illustration 13	g02583478

The following steps describe the proper operations of the FT-1996 Low-Pressure Test Kit. Use these steps with the troubleshooting flow chart and record the results on the record sheet.

1. Perform the preliminary checks such as inspecting fuel filters, checking for waxing, and checking the operation of hand priming pump check valves.

2. Install the FT-1996 Low Fuel Pressure Test Kit. Use the fuel filter unless waxing is observed. Put the test kit return line into the machine's fuel tank.

3. Start the engine and operate at low idle to eliminate trapped air from inside the test kit. Bypass valve (26) can be opened to eliminate trapped air. Close the bypass valve when air is removed.

4. Operate the engine until the engine is at normal operating temperature.

5. Record and enter information on "Record Sheet" for fuel pressure and temperature readings. Also check for air in the sight glass at low idle. Confirm the accuracy of the machine or truck fuel pressure gauge using 1U-5470 Gauge Kit and enter information on "Record Sheet."

6. Open bypass valve while maintaining full load rpm.

7. Record and enter information on "Record Sheet" the fuel pressure and temperature. Check for air in the sight glass.

8. Close bypass valve and return the engine to low-idle and stop engine.

9. Review recorded data for possible repairs.

10. If nothing is found wrong, proceed with troubleshooting using the flow chart.

NSFS Misfire, Test C

Illustration 14	g06334747

Governor Instability, Test D

Illustration 15	g06334751

Fuel Quality, Test E

Illustration 16	g06334753

Injection Pump Cranking, Test F

Illustration 17	g06334758

Plugged Nozzle Orifice and Pop Test, Test G

Illustration 18	g06334763

Fuel Shutoff Solenoid, Test H

Illustration 19	g06334766

Fuel Ratio Control Setting, Test I

Illustration 20	g06334768

Fuel Transfer Pump (Incorrect Pressure), Test J

Illustration 21	g06334771

Fuel Transfer Pump

Illustration 22	g06334772
Typical transfer pump (1) Check valve assembly (2) Spring (3) Cylinder (4) Camshaft (5) Piston (6) Tappet

Fuel Ratio Control Diaphragm Leak, Test K

Illustration 23	g06334775

Line Nut Fuel Leakage

If fuel is leaking from the line nut, tighten the nut to 40 ± 7 N·m (29.50240 ± 5.16292 lb ft). Again check for leakage. Be sure to check fuel injection lines inside valve cover base on 3204 and 3400 Engines.

Table 6

Troubleshooting Guide for Caterpillar 7000 Series Fuel Nozzles (only)
Problem	Cause	Correction
Missing or Moved Tip	1. Cracked body	Replace nozzle assembly
	2. Overheat (melted carbon dam)	Replace nozzle set
Incorrect Opening Pressure	1. Faulty or worn parts	Replace nozzle assembly
Nozzle Will Not Open	1. Plugged orifices	Replace nozzle assembly
	2. Faulty parts	Replace nozzle assembly
Nozzle Did Not Pass "Spray Test Pattern"	1. Plugged or carbon deposits in orifices	Replace nozzle assembly
	2. Cracked tip	1. Replace nozzle assembly
	3. Foreign material in tip bottom	2. Discard if holes are eroded
	4. Nozzle tip was wire brushed	Replace nozzle assembly
Tip Leakage	1. Deposits in seat area	Replace nozzle assembly
	2. Valve seat eroded and pitted	Replace nozzle assembly
	3. Faulty or worn parts	Replace nozzle assembly
	4. Cracked tip	Replace nozzle assembly
High Bleed Screw Hole Flow	1. Excessive wear on guide	Replace nozzle assembly
	2. Faulty or worn parts	Replace nozzle assembly
External Leakage @ Bleed screw	1. Faulty seal washer	1. Replace seal washer
	2. Faulty shell spotface	2. Replace nozzle assembly
	3. Faulty bleed screw	3. Replace bleed screw
External Leakage @ Top or Bottom Seal (@Shell)	1. Excessive pressure	Replace nozzle assembly
	2. Faulty or worn parts	Replace nozzle assembly
	3. Low adapter torque	Replace nozzle assembly
Zero VOP	1. Stuck needle	Replace nozzle assembly
	2. Debris	Replace nozzle assembly
	3. Broken tip	Replace nozzle assembly
	4. Faulty parts	Replace nozzle assembly

Visual Inspection

Housing

Illustration 24	g06322275
Pump housing with damaged seat area.

Do Not Use Again

Timing Spacer

Illustration 25	g06322277
Pump housing timing spacer.

Do Not Use Again

Illustration 26	g06322281
Pump housing timing spacer wear. Arrows point to dents in washer, caused by floating debris in the housing.

Do Not Use Again

Bushing

Illustration 27	g06322282
Bonnet bushing. Rust is acceptable, as long as splines are functional.

Use Again

Illustration 28	g06322285
Bonnet bushing.

If bushing has the skinny nose style - Do Not Use Again

Illustration 29	g06322286
Location of new groove (3) next to load ring (2) on 113-7794, 7C-6617 Bushing (1). Raised area (4) on former 7C-6617 Bushing.

If all other reusability requirements are met - Use Again

A groove has been added to the bottom of bushing (1) (Illustration29) for manufacturing processes. This new groove is not a quality defect.

Nomenclature for Plunger and Barrel Assembly

Illustration 30	g06309520
Plunger and barrel assembly nomenclature. (1) Ring (2) Valve assembly (3) Bonnet (4) Spring (5) Barrel (6) Plunger (7) Gear (8) Retainer (9) Spring

Plunger and Barrel

Illustration 31	g06309530
Bottom view of bonnet (left). Top view of barrel (right (1) This style of bonnet can have staining removed with the chemical cleaning process that is described in this guideline (2) Multiple relief notches are acceptable. (3) Light staining and fretting is not an automatic indication of joint leakage.

Use Again After Cleaning

Illustration 32	g06309541
Heavy rust, do not reuse bonnet

Do Not Use Again

Illustration 33	g06309555
Barrel and bonnet with light staining.

If the barrel can be chemically cleaned - Use Again

Do Not Reuse the Bonnet under any circumstances. Always replace the bonnet with latest design.

Illustration 34	g06321665
Barrel and bonnet with medium staining.

If the barrel can be chemically cleaned - Use Again

Do Not Reuse the Bonnet under any circumstances. Always replace the bonnet with latest design.

Illustration 35	g06321669
Barrel damage caused by debris.

Arrows point to two large nicks. - Do Not Use Again

Illustration 36	g06321681
Barrel damage caused by debris.

• Large nick. Do Not Reuse barrels with this type of damage.

• This mark is the mirror image of the valve assembly notch and the barrel can be reused.

• Width of valve wear ring. Barrels with minor nicks.

• does not extend past this area can be reused.

If mark (2) is present, or if small nicks (4) are less than width (3) - Use Again

Do Not Reuse if large nick (1) is present.

3406 Single and Double Scroll Plunger

The shorter plunger and assembly may contain a single or double scroll plunger. Any fuel injection system that uses 4P-7681 Fuel Injection Pump Groups, may have any combinations of single or double scroll 7E-6007 Plunger and Assemblies. This mixture of single and double scroll plungers will not affect the engine performance. The second scroll helps hydraulically balance the plunger.

Illustration 37	g06321848
End view of 7E-6007 Plungers (A) Single scroll plunger (B) Double scroll plunger (C) Shut-off slot

Illustration 38	g06321851
Plunger and barrel have light scratches.

Use Again

Illustration 39	g06321854
Edge damage on plunger and barrel indicated by arrow.

Do Not Use Again

Illustration 40	g06321858
Plunger

if cavitation erosion (1) above the scroll edge is acceptable - Use Again

Do Not Reuse if plunger has worn or nicked scroll edges (2). Plungers with this type of damage will cause hard starting. Refer to the "High Efficiency Fuel Filters", "Fuel Cap", and "Filter Used With Wiggins Fuel Group" sections.

Note: Do not mix plungers and barrels. The original plunger must remain with the same barrel. If the plunger cannot be reused, a new plunger and barrel assembly is required.

Illustration 41	g06321864
Staining on plunger and barrel.

Use Again

Illustration 42	g06321877
Burrs on plunger.

Do Not Use Again

Illustration 43	g06321881
Plunger, with cracked rack gear tooth.

Do Not Use Again

Illustration 44	g06321884
Plunger and barrel gear teeth damage.

Use Again

Retainer

Illustration 45	g06321890
Typical retainer washer wear on plunger and barrel.

Use Again

Lifter Assembly

Illustration 46	g06322018
Lifter assembly with bent guide pin.

If gear pin can be straightened - Use Again

Illustration 47	g06322021
Lifter assembly shows normal wear.

Clean and - Use Again

Illustration 48	g06322022
Lifter assembly with excessive roller scratches.

Do Not Reuse - inspect the cam lobe for damage

Illustration 49	g06322029
Roller edge damage indicated by arrows.

The frosty-looking appearance is an example of a bad part - Do Not Use Again

Illustration 50	g06322031
Edge wear on lifter notch indicated by arrows.

This type of wear appears as a polished looking surface with no measurable depth (no wear steps)- Use Again

Illustration 51	g06322033
Button inside of lifter assembly. (A) New rough surface with tool marks. (B) Former smooth surface.

Whichever type of surface (A) or (B) is on the button. Machine marks on newer lifter assemblies are not caused by wear and can be used again if all other reusability requirements are met - Use Again

Rack Bar

Illustration 52	g06322212
Rack bar zero-pin slot damage.

Use Again - after deburring

Illustration 53	g06322217
Rack bar damage from rubbing lifter window.

Do Not Use Again

Illustration 54	g06322226
Rack bar scratching and button damage.

Use Again - after deburring

Illustration 55	g06322233
Rack bar button wear.

Use Again

Governor Assembly

Illustration 56	g06322405
Normal wear on the riser flyweight bearing race of the governor assembly.

Use Again

Illustration 57	g06322408
Toe wear, indicated by arrow, on governor flyweight assembly.

Do Not Use Again

Illustration 58	g06322409
Toe wear on governor flyweight assembly.

Do Not Use Again

Illustration 59	g06322411
Governor flyweight with flat toe wear.

Do Not Use Again

Illustration 60	g06322413
Shut-off lever.

If spring is not broken - Use Again

Illustration 61	g06322416
Shut-off shaft.

If visible wear step cannot be felt with a fingernail - Use Again

Illustration 62	g06322417
Governor spring lever for New Scroll Fuel Systems on 3400B and C Engines.

If lever has a polished appearance - Use Again

if lever shows wear steps and/or has flat areas - Do Not Use Again

Illustration 63	g06322419
Governor load stop bolt.

If bolt is dented or worn. A maximum of 0.13 mm (0.00512 inch) material can be removed by polishing - Do Not Use Again

Illustration 64	g06322423
Governor throttle shaft.

If shaft has no detectable wear step pattern - Use Again

Illustration 65	g06322426
Tachometer drive shaft.

If there is no wear visible on the shaft. Polishing is acceptable - Use Again

Illustration 66	g06322427
Spring guide showing typical wear.

If outside of guide is loose - Use Again

Illustration 67	g06322430
Governor spring seat indicating normal wear.

Use Again

Illustration 68	g06322431
Governor spring seat.

Do Not Use Again

Illustration 69	g06322434
Governor spring seat.

Do Not Use Again

Illustration 70	g06322435
Governor spring seat.

Do Not Use Again

Illustration 71	g06322439
Governor spring seat.

Do Not Use Again

Illustration 72	g06322441
Servo sleeve. Scuffed or shiny surface is acceptable.

If any wear steps are visible - Do Not Use Again

Fuel Transfer Pump

Illustration 73	g06333601
Unacceptable repair on fuel transfer pump.

Do Not Use Again

Illustration 74	g06333608
A new fuel transfer pump cover. On used covers, check for cracks and check flange flatness with a straight edge. Straightening of the ears is permitted.

Use Again

Illustration 75	g06333617
Fuel transfer pump piston.

Use Again

Illustration 76	g06333621
Fuel transfer pump piston sleeve with scratches and scuff marks.

If piston has scratches large enough to feel with a fingernail. - Do Not Use Again

Illustration 77	g06333629
Fuel transfer pump piston.

If scratches cannot be felt with a fingernail - Use Again

Illustration 78	g06333635
Scuffing/scratches on fuel transfer pump sleeve.

Do Not Use Again

Illustration 79	g06333638
Housing of fuel transfer pump. Be careful when bead blasting the sealing areas of the housing.

Use Again

Illustration 80	g06333640
Corrosion on fuel transfer pump housing.

Do Not Use Again

Illustration 81	g06333643
Internal damage on fuel transfer pump housing caused by tools used to remove the check valve.

Do Not Use Again

Illustration 82	g06333644
Damage to seal surface of fuel transfer pump cover.

Do Not Use Again

Illustration 83	g06333645
Physical damage to fitting seal surface of fuel transfer pump cover.

Do Not Use Again

Illustration 84	g06333649
Cosmetic damage to fuel transfer pump cover.

Use Again

Illustration 85	g06333651
Fuel transfer pump cover with staking damage.

Do Not Use Again

Illustration 86	g06333655
Staking marks on fuel transfer pump cover.

Use Again

Illustration 87	g06333663
Typical wear pattern on tappet and guide assembly.

If pump can pass the leak test procedure - Use Again

Illustration 88	g06333665
Chipped tappet on a fuel transfer pump guide and tappet assembly.

Do Not Use Again

Illustration 89	g06333669
Stem wear pattern on tappet. Check reusability of stem by using a static leak test procedure.

Timing Advance

Illustration 90	g06333755
Timing advance weight carrier.

If there is a wear step inside the weight pocket - Do Not Use Again

Illustration 91	g06333758
Timing advance weight carrier.

If wear step can be removed with a file - Use Again

Illustration 92	g06333761
Timing advance weight carrier.

Only if pin in weight pocket is above the surface of the housing - Use Again

Illustration 93	g06333765
Timing advance weight.

Only if hard coat covers toe - Use Again

Illustration 94	g06334328
Timing advance weight for 3300 Engines.

If there are no measurable wear steps. A smooth, shiny surface is also acceptable - Use Again

Illustration 95	g06334335
Timing advance for 3400 Engines. Spring wear is visible in bottom of pocket. Shiny appearance is acceptable.

If wear step does not exceed 0.25 mm (0.00984 inch) - Use Again

Illustration 96	g06334341
Timing advance for 3400 Engines.

If there is any measurable wear to the seat - Do Not Use Again

Illustration 97	g06334343
Timing advance retainer showing no measurable wear. This part can be reversed, if needed.

Use Again

Illustration 98	g06334349
Timing advance back seal ring. Arrow indicates damage caused by incorrect installation procedures. A small amount of rust is acceptable.

If any wear steps are visible - Do Not Use Again

Product Improvements

Tamper Resistant Plugs and Bolts Used to Prevent Changes to Air Fuel Ratio Control (FRC) Settings

3208 Engines

Illustration 99	g06335247
Locations of the new 128-7792 (1) and 128-7795 Tamper Resistant Bolts (2) on 3208 Commercial Engines.

The 3208 Commercial Engines will have the new 128-7792 and 128-7795 Tamper Resistant Bolts on the FRC and cover. Illustration 99shows the locations of the new tamper resistant bolts.

3304 and 3306 Engines

Illustration 100	g06335248

The 3304 and 3306 Commercial Engines will have new 128-7794 and 128-7796 Tamper Resistant Bolts on the FRC and cover. Refer to Illustration 100 for the location of the new tamper resistant bolts

3406 Engines

Illustration 101	g06335249

The 3406 Engines with mechanical fuel systems will have new 128-7794 and 128-7796 Tamper Resistant Bolts on the FRC and cover. Refer to Illustration 101 for the location of the new tamper resistant bolts.

3408 and 3412 Engines

Illustration 102	g06335251

The 3408 and 3412 Commercial Engines with mechanical fuel systems will have new 128-7793 and 128-7798 Tamper Resistant Bolts on the FRC and cover. Refer to Illustration 6 for the location of the new tamper resistant bolts. In certain applications, when a dashpot is used, a longer 128-7799 Tamper Resistant Bolt is used in place of the 128-7798 Tamper Resistant Bolt.

Removal and Installation Procedure

If an adjustment is required on a 3208, 3300, or 3400 Series Engine equipped with tamper resistant bolts, the bolts must be removed. Use the procedure that follows to remove the tamper resistant bolts.

1. Use a 1U-5592 (118 degree) Drill Bit or a 1U-5634 (135 degree split point) Drill Bit to drill a 7/64 inch hole in the center of the bolt to be removed.

2. Use a 4C-3365 Screw Extractor (5/32 - 7/32 inch), in the hole drilled in Step 1, to remove the bolt.

3. When installing a new tamper resistant bolt, tighten the bolt until the bolt head shears off approximately 12 ± 3 N·m (8.85072 ± 2.21268 lb ft) for 1/4 inch diameter tamper resistant bolts, or 25 ± 6 N·m (18.43900 ± 4.42536 lb ft) for 5/16 inch diameter tamper resistant bolts.

Table 7

Tamper Resistant Bolts
Part No.	Thread Size	Length
128-7792	1/4 - 20	15.88 mm (0.62520 inch)
128-7793	1/4 - 20	25.40 mm (1.00000 inch)
128-7794	1/4 - 20	28.58 mm (1.12519 inch)
128-7795	1/4 - 20	57.15 mm (2.25000 inch)
128-7796	1/4 - 20	95.25 mm (3.74999 inch)
128-7798	5/16 - 18	60.30 mm (2.37401 inch)
128-7799	5/16 - 18	88.90 mm (3.49999 inch)

Table 7 identifies the part numbers and sizes of available tamper resistant bolts.

Adjustment of Fuel Ratio Control Setting

In certain applications the 3408 (99U) and 3412 (60M) Marine Engines may have more than an acceptable amount of black smoke during acceleration. The fuel ratio control setting for each engine is set at the factory to the maximum permissible amount of fuel. The engine information plate contains the performance specifications and the dynamic fuel ratio control setting. Due to variations in driven equipment and the inertia and torque demands to accelerate the entire system, the factory setting may not be appropriate for every application.

The fuel ratio control can be adjusted to a more restrictive setting that will decrease the amount of fuel and black smoke without affecting engine reliability. The procedure for adjusting the fuel ratio control setting is explained in the "Systems Operation Testing and Adjusting" module in the service manual.

A more restrictive fuel ratio control setting will also cause the engine to be less responsive during acceleration. The fuel ratio control should be adjusted to achieve an acceptable balance between engine response and black smoke during acceleration.

New Diaphragm Used in Fuel Ratio Control Groups

Illustration 103	g06334785
Location of new 6I-1564 Diaphragm in fuel ratio control group.

A new diaphragm is used in the fuel ratio control groups of 3306, 3306B, 3306C, 3406B, and 3406C Truck Engines. Refer to Illustration 103. The new diaphragm is more resistant to tearing, abrasion, and lube oil absorption and will provide increased service life.

The new 6I-1564 Diaphragm is a direct replacement for the former 7W-0802 Diaphragm in the 4P-2507, 7W-2830, 7W-2831, 7W-2832, and 9Y-8087 Fuel Ratio Control Groups.

New Components Used in Fuel Ratio Control Groups

Illustration 104	g06334792
Location of new components in improved fuel ratio control groups. () 4P-7274 Cover () 4P-7275 Cover () 5P-8210 O-ring Seal () Valve extension () 3E-6760 O-ring Seal

Illustration 105	g06334795
Location of new components in earlier fuel ratio control groups. (4) Valve extension (5) 3E-6760 O-ring Seal (6) 1W-2076 Cover (7) 7W-2829 Cover (8) 4P-9608 Gasket

New components are used in the fuel ratio control groups of 3306, 3306B, 3306C, 3406B, and 3406C Truck Engines to help prevent both internal and external air leaks. New covers (1) and (2) use O-ring seal (3) to provide improved external sealing. New O-ring seal (5) on extension valve (4) provides improved internal sealing. Refer to Illustration 103.

New gasket (8) is available for use between former covers (6) and (7) on earlier fuel ratio control groups. The new gasket has improved resistance to extrusion which will help prevent external air leaks. Refer to Illustration 105. New O-ring seal (5) can be used in earlier fuel ratio control groups.

New 4P-7274 Cover (1), 4P-7275 Cover (2), and 5P-8210 O-Ring Seal (3), when used together, are direct replacements for the former 1W-2076 Cover (6), 7W-2829 Cover (7), 7N-9033 Gasket in the fuel ratio control groups. The former covers are not canceled. New 3E-6760 O-Ring Seal (5) is a direct replacement for the former 7J-0204 O-Ring Seal on valve extension (4).

New 4P-9608 Gasket (8) is a direct replacement for the former 7N-9033 Gasket which is canceled.

Improved Fuel Ratio Control (FRC)

Illustration 106	g06334819
Fuel ratio control. (1) 115-3358 Lock Washer (2) 106-6493 Diaphragm Seal Washer (3) Locations where the edges have been smoothed.

The FRC has been improved on 3306, 3306B, 3306C, 3406B, and 3406C Truck Engines to help extend serviceable life of the diaphragm. The edges of the components that contact the diaphragm have been smoothed to help prevent damage to the diaphragm. The new diaphragm seal washer will help reduce leakage. A new lock washer will help prevent loosening of the locknut (refer to Illustration 106).

The new 106-6493 Diaphragm Seal Washer is a direct replacement for the former 7W-1691 Diaphragm Seal Washer. The new 115-3358 Lock Washer is an addition to the group. The FRC improvements are effective with 3306C (9TL4656) Truck Engine and 3406C (8PN1, 3ZJ61100) Truck Engines. The new diaphragm washer and lock nut washer are adaptable to the FRC's on 3306 and 3306B (63Z1-UP), 3306C (7RJ1-UP, 9TL1-UP), 3406B and 3406C (3ZJ1-UP, 5KJ1-UP, 4MG1-UP, 7FB1-UP) Truck Engines

Air Line Routing for 3306 Truck Engines in Kenworth Trucks

Table 8

Parts Needed
Part Number	Description	Quantity
9N-3040	Hose Assembly	1
067-6495	Flared Elbow	1
6K-1972	Elbow	1
8T-6764	Plug	1

Illustration 107	g06334823
Illustration of new FRC air line routing. (1) Hose assembly (2) Plug (3) Elbow (4) Flared elbow

1. Remove 8T-6762 Plug.

2. Install 6K-1972 Elbow.

3. Remove 2N-1287 Elbow.

4. Install 8T-6764 Plug.

5. Install 067-6495 Flared Elbow, to the end of the 1W-2128 Tube Assembly.

6. Install 9N-3040 Hose Assembly to the 067-6495 Flared Elbow, and to the 6K-1972 Elbow.

The new FRC air line routing is designed specifically for the Kenworth trucks that use the rear intake port in the 3306 Engine's Cylinder Head. The new routing will eliminate moisture entry into the FRC housing, preventing its components from internal corrosion and future failure.

Refer to Table 8 and Illustration 107 for components used in the new FRC air line routing for Kenworth trucks.

Note: If the dynamic full torque setting cannot be reached, a repair or replacement of the fuel ratio control is needed.

Adjustment of Fuel Ratio Control Setting (Engines without NSFS)

In certain applications 3408 (99U) and 3412 (60M) Marine Engines may have more than an acceptable amount of black smoke during acceleration. The fuel ratio control setting for each engine is set at the factory to the maximum permissible amount of fuel. The engine information plate contains the performance specifications and the dynamic fuel ratio control setting. Due to variations in driven equipment and the inertia and torque demands to accelerate the entire system, the factory setting may not be appropriate for every application.

The fuel ratio control can be adjusted to a more restrictive setting that will decrease the amount of fuel and black smoke without affecting engine reliability. The procedure for adjusting the fuel ratio control setting is explained in the "Systems Operation Testing and Adjusting" module in the Service Manual. This adjustment should be made by a Cat dealer.

A more restrictive fuel ratio control setting will also cause the engine to be less responsive during acceleration. The fuel ratio control should be adjusted to achieve an acceptable balance between engine response and black smoke during acceleration

Bushing

A new bushing is used with the high lift fuel injection pump camshaft and shorter 4P-7681 Pump Plunger and Barrel. The new bushing must not be used on fuel injection pump groups without the high lift camshaft and shorter pump plunger and barrel. Also, the former bushing must not be used on the new fuel injection pump groups with the high lift camshaft.

Table 9

New Bushings
Engine Model	Engine Serial Number
3406 Machine	7OV35127 - Up, 41Z1 - Up, 11N1 - Up
3406C Truck	5JK465 - Up , 3ZJ1 - Up , 8YN1 - Up
3406B PEEC Truck	8TC13823 - Up , 2EK1 - Up , 4CK1 - Up
Industrial and Marine	6TB8039 - Up , 4TB2989 - Up , 2WB9833 - Up, 4RG1000 - Up

The new 4P-2899 113-7794 Bushings are in effect, as listed in Table 9. The 4P-2899 113-7794 Bushings should not be used to replace a 7C-6617 Bushing, and a 7C-6617 Bushing should not be used to replace 4P-2899 113-7794 Bushings. Former 7C-6617 Bushing did not have raised area (4) Illustration 29) on the top surface.

Note: For additional information, refer to Service Magazine, 21, September 19922, "New Fuel Injection Pump Groups Have Larger Diameter Camshaft Bores, New Lifter Assembly, And Shorter Plunger And Barrel Assembly" on 3406B and 3406C Engines.".

Pump Housing

Illustration 108	g06322369
Location of two 9J-0114 Racesand one 7D-1189 Bearing (1) 4P-0984 Front Cam Bearing (2) 4P-0985 Center Cam Bearing (3) 4P-0986 Rear Cam Bearing (4) 7E-5888 Housing

Table 10

Models Affected by New Pump Housings
Engine Model	Serial Number
3406B Industrial	3406B 1st Production - 6TB8038
3406B Marine	3406B 1st Production - 4TB2988
3406B Generator	3406B 1st Production - 2WB9832
3406B Vehicular	N/A
3406B Truck	7FB1 - uP, 8TC1 - 13822, 4MG1 - Up, 5KJ1 - 464

The 7E-5888 Fuel Injection Pump Housing (used on 1991 engines) is the service replacement for pre 1991 fuel injection pump housings on the 3406 Engines listed in Table 10. The newer 7E-5888 Fuel Injection Pump Housing has a larger diameter camshaft bearing bore than the pre 1991 pump housings. Therefore, thicker bearings are required (to work with the smaller diameter pump camshaft) when using the 1991 pump housing to replace a pre 1991 pump housing.

Use a 7E-5888 Fuel Injection Pump Housing, two 9J-0114 Races, one 7D-1189 Bearing (1), 4P-0984 Front Cam Bearing (2), 4P-0985 Center Cam Bearing (3), and 4P-0986 Rear Cam Bearing (4) replacing fuel injection pump housings on the 3406B Engines identified in Table 10.

Timing Spacer

Illustration 109	g06322385
Cross-section of fuel injection pump. (10) Timing spacer

Table 11

Timing Spacers
Spacer Part Number	Model 3406 Serial Number
7E-9907	5KJ465, 8TC13823, 3ZJ1 - Up, 2EK1 - Up, 6TB38039, 4TB2989, 2WB2989, 2WB9833, and 4RG1000
7E-8528	5YG1 - Up
8N-0672	7FB1 - Up, 4MG1 - Up, 5KJ1 - 464, 8TC1 - 13822

Using the correct timing spacer (10) is critical for the fuel injection pump to work efficiently. Use Table 11 and the part numbers and engine serial numbers to make sure that the appropriate timing spacer is used.

Bushing O-ring Seal

An improved 131-3719 O-ring Seal replaces the former 9X-7735 O-ring Seal for the injection pump groups in 3406B (7FB, 7XC, 8TC, 4MG, 5YG, 3ZJ, 5KJ, 2EK, 4CK), and 3406C (3ZJ, 4CK, 8PN) Truck Engines. The improved O-ring seal has a slightly larger outside diameter which creates a better pilot surface on the bushing chamfer during assembly. The chance of cutting the seal is lessened. The improved O-ring seal is identified by its pink color. The former O-ring seal is blue. The 9X-7735 O-ring Seal seal is still available for use in other applications

Pump Housing Seals

New seals with improved heat set resistance in 3406B & C Engines are being used in the fuel injection pump and the fuel injection pump fastener group. After a high number of miles, the former seals could take a permanent set resulting in leaks. The new seals will provide extended service life.

Illustration 110	g06322334
Location of new seals in fuel injection pump fastener group.

• (1) 6V-7681 Seal

• (2) 5P-5846 Seal

• (3) 2N-3350 Seal

Illustration 111	g06322339
Location of new seals in fuel injection pump group. (Seals (4), (5), and (6) are on the opposite side of the pump housing.)

• (4) 109-3206 Seal

• (5) 5P-7813 Seal

• (6) 109-9685 Seal

Table 12

New Fuel Injection Pump Fastener Group Seals
Item	Quantity	New Part Number	Description	Former Part Number
1	1	6V-7681	Seal	6F-4718
2	1	5P-5846	Seal	9M-9647
3	1	2N-3350	Seal	1S-0004

Table 13

New Fuel Injection Pump Group Seals
Item	Quantity	New Part Number	Description	Former Part Number
4	1	109-3206	Seal	1J-9671
5	2	5P-7813	Seal	7J-0204
6	1	109-9685	Seal	4J-7533

Illustration 110 and Table 12 identify the new seals in the fuel injection pump fastener group. The new fuel injection pump fastener group seals are in effect with 3406C Truck Engines 3ZJ49546, 4CK24376, and 8PN1. The new seals are adaptable to all earlier engines with new scroll fuel systems.

Illustration 111 and Table 13 identify the new seals in the fuel injection pump group. The new fuel injection pump group seals are in effect with 3406C Truck Engine 3ZJ55312 and 8PN1. The new seals are adaptable to all earlier engines with new scroll fuel systems.

Oil and Fuel Leak Resistance

A new O-ring seal and gaskets are made with materials that are capable of resisting higher temperatures. As a result, the improved parts can provide greater resistance to oil and fuel leaks in the pump and governor.

Illustration 112	g06322352
Section view of housing. (1) 144-0479 Gasket

Illustration 113	g06322359
3406C Governor And Fuel Injection Pump Group (C) Side view. (D) Rear view. (2) 144-0481 Gasket. (3) 8J-4351 O-Ring Seal. (4) 144-0478 Gasket. (5) 144-0480 Gasket

Illustration 114	g06322364
3406C Fuel Injection Pump Group (E) Front view (6) 144-0482 Gasket

Table 14

O-Ring Seal and Gaskets
Description	Former Part Number	New Part Number
O-ring Seal	1H-9696	6J-4351
Gasket	8N-3763	144-0478
Gasket	8N-3765	144-0479
Gasket	8N-9374	144-0482
Gasket	8N-9382	144-0481
Gasket	8N-9384	144-0480

Table 14 lists the new and former O-ring seal and gaskets that are contained in the governor and fuel injector pump group on all Caterpillar 3406B and 3406C Engines with the New Scroll Fuel System (NSFS).

The improved O-ring seal and gaskets are effective with serial number 41Z6538-Up and are adaptable to first production of all Caterpillar 3406B and 3406C Engines with the New Scroll Fuel System.

Governor Weights (3204, 3300and 3400 Engines)

A new governor weight and race can be used to replace the former governor weight and race. The new weight and race provides a wider contact area between the two parts to improve wear resistance for increased service life.

Illustration 115	g06322444
Typical Governor Group (1) New 133-8890 Race (2) New 119-8699 Weight

The new 119-8699 Weight (four weights required for each governor) replaces the former 7N-7264 Weight in the governor. The new 133-8890 Race (two races required for each governor) replaces the former 7E-4892 Race in the governor. The new weight and race are effective with the 3406C (8PN106-UP) Truck Engine. The new weight and race are adaptable to first production of the 3404, 3400 and 3406 Engines with NSFS.

Governor Weights (3408 and 3412 Engines without NSFS)

A new governor weight and race kit has been released for service of 3408 and 3412 Engines using the standard 10% Caterpillar governor. The new governor weight and race kit has a wider weight contact surface and a wider race. The increased contact width will extend flyweight life in severe applications.

Table 15

Governor Weight and Race Kits
Engine Model	Serial Number
D9N Track-Type Tractors	1JD1 - Up, 6XJ1 - Up
D10N Track-Type Tractors	2YD1 - Up, 3SK1 - Up
988F Wheel Loaders	8YG11 - Up
990 Wheel Loaders	7HK1 - Up
992C Wheel Loaders	49Z1 - Up
992D Wheel Loaders	7MJ1 - Up

Table 16

New Governor Servo Components
Item	Quantity	New Part Number	Description
1	1	6V-7681	Bolt (1)
2	1	5P-5846	Piston Assembly
3	1	2N-3350	Washer
4	1	6V-7681	Sleeve
5	1	5P-5846	Ring ?
6	1	2N-3350	Dowel
7	1	5P-5846	Dowel
8	1	2N-3350	Riser

(1)	Not a new component, but this component should be replaced when the other new components are installed.

The new 136-1120 Governor Weight and Race Kit is adaptable to 10% regulated governors containing a 1W-4641 Riser and can service 3408 and 3412 Engines with the low idle lug feature in machines listed in Table 10.

Governor Flyweight Shield No Longer Used in New Scroll Fuel Systems

3406B (7FB) and 3406C Truck Engines that are equipped with governor flyweight shields. Field reports have indicated that the shield can loosen from the flyweight carrier and come into contact with the flyweights and rack control linkages. The purpose of the flyweight shield was to keep any excess oil in the governor housing from splashing against the flyweights. Tests have proven that excess oil does not normally build up in the housing. The flyweight shield was discontinued on production machines, and a field rework program announced.

Many engines have already been reworked. Check the serial number of your engine. If it is in the 7FB1-7FB06809 range, the flyweight shield may not have been removed yet. If you have an engine with an affected serial number and you are not sure if the flyweight shield has been removed, inspect the governor housing and see if the flyweight shield has been removed. If the flyweight shield has not been removed, a convenient time can be scheduled by the dealer to have this done. The rework takes approximately three hours to complete.

Governor Spring Guide

When installing a new governor spring guide in the governor housing, be sure to press the guide to the correct depth.

Illustration 116	g06322460
Press governor spring guide (2) into governor housing (1) to depth (x) of 1.40 ± 0.25 mm (0.05512 ± 0.00984 inch)

For 3204, 3304, and 3306 Engines, press governor spring guide (2), Illustration 116 into governor housing (1) to a depth of 1.40 ± 0.25 mm (0.05512 ± 0.00984 inch).

Illustration 117	g06322464
Press governor spring guide (3) into governor housing (4) to depth (y) of 11.80 ± 0.25 mm (0.46457 ± 0.00984 inch).

For 3406B and 3406C Engines, press governor spring guide (3), Illustration 117 into governor housing (4) to a depth of 11.80 ± 0.25 mm (0.46457 ± 0.00984 inch).

Governor Servo Components (for engines without NSFS)

Illustration 118	g06322454
Location of new servo components in a typical governor group.

Illustration 119	g06322455
Location of new servo components in a typical governor group.

Table 17

Governor Servo Components
Caterpillar Machines Powered By 3408 Engines	67U17413-Up, 48W40563-Up
3412 Engines, With Standard 10 Percent Regulation Governors Containing a 1W-4642 Riser	38S18228-Up, 73W17519-Up

The improved governor servo components are for 3408 and 3412 Engines with energized-to-run solenoids and are identified in Illustrations 118 and 119, and in Table 10. The improved components are in effect and adaptable to all earlier engines.

The new governor servo components identified in this section are NOT compatible with 3% dashpot governors or 10% Caterpillar governors that have a low idle lug feature, using a 1W-4641 Riser.

Changes in Engine RPM; Governor Does Not Operate Correctly

Reports show that some 3408 Engines (without NSFS) equipped with Hydramechanical Governors have had trouble with surges (changes) in engine rpm. It has been found that the cause of this problem in many applications is low oil pressure in the governor hydraulic servo mechanism. The governor servo will operate at low oil pressure, but its action may not be correct. This is because the low oil pressure cannot move the rack as rapidly as is necessary. The procedure that follows can be used in troubleshooting the cause of the low oil pressure.

Show/hide table

Illustration 120	g06322468
Test location for governor oil pressure and location of orifice.

1. Check the governor oil pressure at the fuel transfer pump. Refer to Illustration 120. The specification for the governor oil pressure is 620 - 690 kPa (90 - 100 psi) when the engine rpm is between low and high idle. But, a governor oil pressure of 585 - 760 kPa (85 - 110 psi) is acceptable.

2. Check the engine oil pressure. Acceptable oil pressures are 205 ± 25 kPa (30 ± 4 psi) at 800 rpm and 380 ± 25 kPa (55 ± 4 psi) at 2000 rpm

3. If low oil pressures are found in Steps 1 or 2, the cause of these must be found and corrected. Some possible causes are:
   Show/hide table

   Illustration 121	g06322470
   Location of bypass valve and governor oil pump.

   1. A restriction in the oil flow, such as a plugged orifice in the fuel transfer pump housing. Refer to Illustration 121. This orifice is a passage for oil into the governor oil pump. The diameter of this orifice must be 1.57 mm (0.06181 inch). If this diameter is too small, the servo mechanism will not get enough oil.

   2. A failure of the governor oil pump.

   3. Bypass valve does not operate. The valve may be held open.

Needle Valve Body

Illustration 122	g06322473
Location of the 4N-5485 Valve Body in the fuel injection pump governor group.

The 4N-5485 Valve Body used with 3406C (8PN2906) Truck Engines and can be used to replace the 7W-4182 Valve Body in the former fuel injection pump governor group on all earlier 3406C (8PN) Truck Engines.

Engine testing shows the new needle valve body and a needle valve adjustment will correct low idle surging.

If a new valve body is installed, the 5F-9144 Body Seal and 6H-9691 Needle Valve Seal must also be replaced. Tighten the new valve body to a torque of 6.25 N·m (55 lb in). After the new valve body is installed, turn the needle valve clockwise until it bottoms in the new body, then turn the needle valve counterclockwise 1/2 turn. Additional adjustment may be required if other driveability problems (deceleration/acceleration) are encountered.

With cold engine oil, the 1/2 turn needle valve adjustment may slow rack movement to the "fuel on" position. If the engine does not start on the first try, before attempting to start again, fully depress the throttle pedal for 10 seconds minimum. Then release the throttle pedal and start the engine as described in the Operation and Maintenance Manual.

Over Fueling Spring No Longer Used in Governor

Illustration 123	g06322476
Location of 7N-7267 Over Fueling Spring

Tests have shown that the 7N-7267 Over Fueling Spring used in the governor on 3406 and 3406C Truck Engines is not required. Refer to Illustration 123. The test also indicates that the over fueling spring can decrease the ability to start in cold weather.

The 7N-7267 Over Fueling Spring is no longer included in the fuel injection pump groups. The change is in effect with Fuel Injection Pump Serial No. 30148.

The 7N-7267 Over Fueling Spring should be removed from earlier fuel injection pump groups used on the above engines if cold weather starting is a problem.

Note: To start an engine when the over fueling spring is removed, the operator should push the accelerator pedal to the floor while cranking, then release the accelerator pedal when the engine begins to run.

Shorter Rack Shutoff Solenoids

The former 2N-2384 (12 volt) and 2N-2385(24 Volt) Rack Shutoff Solenoids were canceled and replaced by 8C-3666 8C-3667 Rack Shutoff Solenoids respectively. The former solenoid bodies were 112.8 mm (4.44094 inch) long and the replacement solenoid bodies are 137.0 mm (5.39369 inch) long. The replacement solenoids are 24.2 mm (0.95275 inch) longer and in some applications that are too long. If the former 2N-2384 2N-2385 Rack Shutoff Solenoids have more than 31.8 mm (1.25197 inch) length clearance with adjacent engine parts, use 8C-3666 8C-3667 Rack Shutoff Solenoids as replacements.

New 102-3505 (12 volt) and 102-3506(24 Volt) Rack Shutoff Solenoids are available. The bodies of these solenoids are 111.0 mm (4.37007 inch) long. If the former 2N-2384 2N-2385 Rack Shutoff Solenoids have less than 31.8 mm (1.25197 inch) length clearance with adjacent engine parts, use 102-3505or 102-3506 Rack Shutoff Solenoids as replacements.

Gaskets

Illustration 124	g06322651
Location of cover (1), bolts (2), cover (3), and bolts (4) on new scroll fuel system governors.

Illustration 125	g06322658
Location of electrical shut-off solenoid gasket.

New gaskets are used on the fuel system governors of the 3204 Engines and the 3300 Family of Engines. A new gasket is used under cover (1) for the high idle adjustment screw and cover (3) for the torque rise and fuel setting adjustment screws. A new gasket is also used under the electrical shut-off solenoid. The new gaskets will help prevent leaks. New washers are used under the bolt heads on bolts (2) and (4) that attach covers (1) and (3) to the governor housing. The new washers will help prevent the bolt heads from damaging the covers.

The 6I-2003 Gasket is a direct replacement for the former 8N-3263 Gasket used under high idle cover (1). The 6I-2004 Gasket is a direct replacement for the former 8N-3264 Gasket used under load stop cover (3). The 8N-3263 8N-3264 Gasket are canceled. The new 6I-2002 Gasket is a direct replacement for the 2W-5447 Gasket used under the electrical shut-off solenoid. The 2W-5447 Gasket is not canceled.

A new 5P-0537 Washer is used under the heads of two bolts (2). A new 8T-0328 Washer is used under the heads of two bolts (4).

Governor Control Cover Assembly Includes New Seal and Improved Cover

The governor control cover assembly includes a new governor shaft seal and an improved governor control cover. The seal is more resistant to heat damage and the improved governor control cover provides governor shaft support. This helps reduce side loading of the seal which can result in seal damage.

The 7N-8780 Governor Control Cover Assembly (with the improved governor control cover and new 138-9507 Seal) is effective with 3304 (07Z3498) Machine Engines. The 7N-8780 Governor Control Cover Assembly (with the improved governor control cover and new 138-9507 Seal) is effective with 3306 (08Z96956) Machine Engine in 627 and 637 Scrapers and with 3306 (08Z97573) Machine Engine in all other machines. The truck engine effective serial number is 9TL1589.

The part number of the 7N-8780 Governor Control Cover Assembly (with the improved governor control cover and new 138-9507 Seal) has not changed. The improved governor control cover is not serviced separately and is only available as the 7N-8780 Governor Control Cover Assembly. The new 138-9507 Seal is a direct replacement for the former 5P-3272 or 8T-2604 Seals. The seal is adaptable to all earlier governor control cover assemblies.

3406C Governor Changes Provide Improved Oil and Fuel Leak Resistance

A new O-ring seal and new gaskets are made with materials that are capable of resisting higher temperatures. As a result, the improved O-ring seal and gaskets can provide greater resistance to oil and fuel leaks in the pump and governor.

Table 18

Effective Engine Serial Numbers
Engine	Serial Number
3406B	4TB5972-Up 6TB17301-Up
3406C	3ER2014-Up 4ZR2828-Up 1LS447-Up 41Z6538-Up Machine Engine 8PH12072-Up Truck Engine

Table 19

O-ring Seal and Gaskets
New Part Number	Former Part Number	Description
8J-4351	1H-9696	O-ring Seal
144-0478	8N-3763	Governor Gasket
144-0479	8N-3765	Governor Gasket
144-0482	8N-9374	Pump Gasket
144-0481	8N-9382	Governor Gasket
144-0480	8N-9384	Governor Gasket

Table 19 lists the new and former O-ring seal and gaskets that are contained in the governor and fuel injector pump group on all 3406B and 3406BC Engines with the New Scroll Fuel System (NSFS).

The new O-ring seal and new gaskets are adaptable to first production of the 3406B and 3406BC Engines. The new O-ring seal and new gaskets become effective with the engine serial numbers.

Illustration 126	g06331889
3406C Governor Group (Rear view)

Illustration 127	g06331892
View of Section A-A from Illustration 126. (1) 144-0479 Gasket

Illustration 128	g06331894
3406C Governor and Fuel Injection Pump Group (Side and Rear view) (2) 144-0481 Gasket (23) 8J-4351 O-ring Seal (4) 144-0478 Gasket (5) 144-0480 Gasket

Governor Control Cover Assembly

The governor control cover assembly includes a new governor shaft seal and an improved governor control cover. The seal is more resistant to heat damage and the improved governor control cover provides governor shaft support. This helps reduce side loading of the seal which can result in seal damage.

The 7N-8780 Governor Control Cover Assembly (with the improved governor control cover and new 138-9507 Seal) is effective with 3304 (07Z3498) Machine Engines, 3306 (08Z96956) Machine Engines in 627 and 637 Scrapers, and with 3306 (08Z97573) Machine Engines.

The 7N-8780 Governor Control Assembly part number (with the improved governor control cover and new 138-9507 Seal) has not changed. The improved governor control cover is not serviced separately and is only available by ordering the 7N-8780 Governor Control Cover Assembly. The new 138-9507 Seal is a direct replacement for the former 5P-3272 or 8T-2604 Seals. This seal is adaptable to all earlier governor control cover assemblies.

New Bonnet, Insert, and Fuel Lines Groups (3306 Engines)

Illustration 129	g06321911
Location of the new 6I-1327 Bonnet (1) and 7C-9966 Insert (2) in the 4P-9827 Fuel Injection Pump Group.

A new bonnet and insert are used in the 4P-9827 Fuel Injection Pump Group on 3306C (7RJ) Truck Engines. The new bonnet has an internal spherical spring seat and that requires the new insert. Refer to Illustration 129. This change is required for the higher injection pressures to prevent bonnet cracking. This design is also used in some machine engines with 10.50 mm (0.41339 inch) diameter injection pumps.

The 4P-9827 Fuel Injection Pump Group with the new 6I-1327 Bonnet and 7C-9966 Insert can be used as a direct replacement for the earlier 4P-9827 Fuel Injection Pump Group with the 1W-9171 Bonnet. All new parts can replace the former parts. However, if a machine is already equipped with the new parts, former parts cannot be used as replacements. The new bonnet and insert are in effect with fuel injection pump sequence number 341571, and with 3306CTruck Engine 7RJ2695.

After installing a new bonnet, new fuel lines groups are required because the new 6I-1327 Bonnet is approximately 3.0 mm (0.11811 inch) longer than the former 1W-9171 Bonnet. The new 100-5673 100-5674 Fuel Line Groups and are used on engines in Ford Trucks. The new 100-4634 100-4635 Fuel Line Groups are used on other OEM trucks. The new fuel lines can be used with the older bonnets by gently bending the new lines until the nuts can be started without forcing the lines into place. After installation purge the air and tighten the fuel line nuts to 40 ± 7 N·m (30 ± 5 lb ft). Loosening some of the clamps may be required to service individual lines. Install clamps and tighten them to 27 N·m (20 lb ft).

Check Valves (3406 Engines)

Illustration 130	g06321921
4P-9258 Valve Assembly. Identified with a punch mark on top.

Illustration 131	g06321924

Illustration 132	g06321925

Table 20

New Component Adaptability
Engine Model	New Part Number	Engine Serial Number
3406B Truck	4P-7688	8TC1 - Up, 2EK1 - Up
3406B and 3406C Truck	4P-7688	3ZJ1-347631, 3ZJ1-354592, 4CK1 - 12168, 4MG1 - Up, 5KJ1 - Up and 7FB1- Up
3406B and 3406C Truck	4P-9258	3ZJ34764 - Up (1), 3ZJ35460 - Up (2), and 4CK12169 - Up
3406C Truck	115-5705	8PN1 - Up

(1)	425 hp rating only
(2)	All rating other than 425 hp

As a result of changing emission requirements, there have been several designs of fuel injection pump check valves. The pumps check valve (2), Illustration 129) is located in the bonnet and maintains stable hydraulic pressure during fuel injection. The different valves can be identified by the markings shown in Illustrations 130,131, and 132. Table 20 identifies the correct check valve for each engine.

High-Efficiency Fuel Filters

Table 21

Fuel Filter Reference
Standard Fuel Filter	Typical Engine Application	High-Efficiency Fuel Filter
1R-0712	3176 3400	1R-0749 3176 3400 HEUI
1R-0715	3500 Machine	1R-0755
1R-0718	3500 Stationary	1R-0756 (1)
1R-0725	3600	N/A
1R-0740 (2)	3116 MUI Truck 3200 3300	1R-0705 3200 3300
1R-0740	3114 3116 3126 Truck	1R-0759
1R-0740	3116 Hex	1R-0753 (3)
1R-0740	3126 HEUI - MUI Truck, Industrial, Marine	1R-0751

(1)	Cartridge
(2)	Temporarily covered by the 1P-2299 Filter.
(3)	Approximately 50 percent more capacity for 320 and 325 Excavators.

Note: For additional information, refer to Information Release Memo FIL96-8, "Caterpillar High Efficiency Fuel Filters", Form No. PELE0503

A line of Caterpillar high-efficiency fuel filters is available. The use of these high-efficiency fuel filters will help provide maximum life for the fuel system components in Caterpillar commercial engines (except the 3600 Engines). The standard fuel filters will remove particles 15 microns in diameter and larger from the fuel. The high-efficiency fuel filters will remove particles 2 microns in diameter and larger from the fuel. The use of the high-efficiency filters will result in the quicker removal of more debris from the fuel system. This will result in less wear on the tight tolerances of the fuel system components such as fuel injection pumps and fuel injection nozzles.

Use Table 21 to determine which fuel filter should be used

Fuel Cap

A retrofit of the corporate fuel cap to fit the 120.7 mm (4.75196 inch) threaded fuel tank filler neck is now available.

The 7X-7700 Fuel Cap Assembly can be retrofitted and used on 120.7 mm (4.75196 inch) threaded fuel tank filler neck using two adapters. The 125-7873 Adapter and 9X-2207 Adapter Kit are screwed onto the fuel tank filler necks. The 7X-7700 Fuel Cap Assembly is then mounted on the filler neck.

The change is adaptable to all next higher levels of the 4B-1455 Fuel Cap Assemblies, which may be serviced with the 9X-2207 Adapter Kit, 125-7873 Adapter, and 7X-7700 Fuel Cap Assembly.

Filter Used with Wiggins Fuel Group

Illustration 133	g06321999
Dimensions for fabrication of 2M-6025 Plate

• (AA) 25.0 mm (0.98425 inch)

• (BB) 12.5 mm (0.49213 inch)

• (CC) 13.0 mm (0.51181 inch)

• (DD) 90.0 mm (3.54330 inch)

• (EE) 63.5 mm (2.50000 inch)

• (FF) Drill 8.2 mm (0.32283 inch)

• (GG) 50.0 mm (1.96850 inch) hole 25.0 mm (0.98425 inch) deep, tap ⅜ - 16 class B thread 17.0 mm (0.66929 inch) deep (2 holes).

Illustration 134	g06322001
View of 114-0937 Fuel Tank Group (not serviced) with new Wiggins vent filter.

Table 22

New Parts Used for Wiggins Fuel Service Center Vent Filter in 114-0937 Fuel Tank Group (not serviced)
Item	Quantity	Part Number	Description
1	1	5P-2230 (1)	1R-0749 3176 3400 HEUI
2	1	6V-8400	1R-0755
3	1	8T-4896	1R-0756
4	2	8T-9101 (2)	N/A
5	1	105-0381	1R-0705 3200 3300
6	1	139-0156 (3)	1R-0759
7	1	7M-8485	1R-0753 (4)
8	1	8C-3364	1R-0751
9	1	9M-0164 (5)
10	1	8X-4575

(1)	This component directly replaces the former 9M-7958 Hose Clamp
(2)	This component directly replaces the former 5M-3062 Bolt.
(3)	This component directly replaces the former 038-6027 Hose Assembly.
(4)	Approximately 50 percent more capacity for 320 and 325 Excavators.
(5)	This component directly replaces the former 7D-7233 Clip.

Note: For additional information, refer to Service Magazine, 02, July 1990, "Welding on Fuel and Hydraulic Tanks", Page 1 and Special Instruction, SEHS9980, "793C Off-Highway Truck Assembly Procedure", Pages 55 through 57; "Installation of 131-7956 Fuel Tank Group Using 115-7665 Fuel Tank Fastener Group".

A filter attachment is now used in some fuel tank groups to filter air entering the tank through the Wiggins fuel service center vent and maintain cleaner fuel during truck operation.

The parts listed in Table 9 are now used in 114-0937 Fuel Tank Group (not serviced) effective with 776D (5ER87) Tractor and 777D (3PR298) Off-Highway Trucks. This change can be made to all previous 776C (2TK1-Up), 776D (5ER1-86) Tractors, 777C (4XJ1-Up) and 777D (3PR297) Off-Highway Trucks.

Both retrofit options require the addition of 2M-6025 Plate which must be welded to the Truck. If the 2M-6025 Plate is not available through parts distribution, a plate can be fabricated using the specifications shown in Illustration 133.

For additional fuel tank venting information, refer to Special Instructions, SEHS9655, "Installation of High-Level Fuel Tank Vent and Modification of Fuel Tank Caps for Challenger Tractors".

Two options are available for retrofitting 114-6352 Fuel Tank Assembly for the new Wiggins fuel service center vent filter attachment. The first option is to replace the existing 114-6352 Fuel Tank Assembly with the newly designed 114-6352 Fuel Tank Assembly with relocated Wiggins fuel service center vent orifice. The second option is to relocate the Wiggins fuel service center vent orifice by cutting a new hole in the existing 114-6352 Fuel Tank Assembly and plugging the existing orifice.

Steel Fuel Pump Lifter

A new steel lifter with a wider, crowned roller follower is available for use in the fuel injection pumps used on the 3400 Vehicular, Industrial, Marine, and Truck Engines. The wider roller spreads the load over the camshaft lobe to reduce stress and lobe wear. Also, the new steel lifter is more durable than the former aluminum lifter.

The 9N-2505 Lifter Assembly has been canceled. For parts service of the 9N-2505 Lifter Assembly, order one of each of the following: 4W-0736 Lifter Assembly, 7N-1066 Washer, and 7N-1208 Spring.

Fuel Rack Slots (3408, 3412 Engines without NSFS)

Illustration 135	g06322246
Dimensions for 4N-1572 Cross Link and fuel rack slot.

Cross link:

• (2) Fuel rack

• (A) 9.60 ± 0.013 mm (0.37795 ± 0.00051 inch)

• (B) 9.652 ± 0.013 mm (0.38000 ± 0.00051 inch)

Illustration 136	g06322248
Location of 9S-4160 Bearings (3).

The method by which the fuel rack slots are hardened on all 3408 and 3412 Engines has been improved. This will give better wear resistance in the areas where the fuel rack comes in contact with the 4N-1572 Cross Link. The basic dimensions for the fuel rack slot and cross link are shown in Illustration 135. The maximum total wear between the fuel rack slot and cross link ball head must not exceed 0.13 mm (0.00512 inch). We also recommend that a new 9S-4160 Bearing be installed when any new fuel rack is installed, as shown in Illustration 136. Use the procedure in the Service Manuals for 3408 Engines.

Illustration 137	g06322253
New (5) and former (4) fuel rack tooth patterns.

The 4N-0900 (right) and 4N-0901 (left) Fuel Racks are a direct replacement for the former fuel racks. The part numbers did not change. A different tooth pattern can be used for identification of the new and former fuel racks. Refer to Illustration 137.

Fuel Pump Drive Group

Illustration 138	g06334354
Location of new components in 4W-4619 Governor and Fuel Pump Drive Group.

Some of the components in the governor and fuel pump drive group were changed to accommodate the new larger spline drive fuel pump camshaft.

Table 23

New Components in the 4W-4619 Governor and Fuel Pump Drive Group
Callout	Quantity	New Part Number	Description	Former Part Number
(1)	1	4P-1368	Carrier	1W-5436
(2)	1	4P-1369	Body	4W-4618
(3)	1	9X-7715	Seal	4W-0436
(4)	1	5H-0793	Ring	8F-1145

The new components are effective with 3406 (11N1, 70V35127) Engines.

Electronic Timing Advance

Table 24

Electronic Timing Advance Steps
Engine Serial Number Range	Applicable Steps
8TC1-UP	1-4, 6-9
8TC1-13234	5
2EK1-UP	1-4, 7-9
2EK1-01823	6
4CK1-UP	3, 7, 9
4CK1-2537	1
4CK1-6001	2
4CK1-11473	4
4CK1-15840	9

• Steps 1 through 3 can be performed without removing the cover.

• Steps 4 through 7 require removal of the cover.

• Step 8 requires disassembly of the timing advance.

• Step 9 requires removal of the governor if the gasket is leaking.

Numerous improvements have been made to the electronic timing advance components on 3406B (8TC, 2EK) and 3406C (4CK) Truck Engines. The steps that follow provide a way to check the electronic timing advance components to determine if the latest components and improvements are incorporated. Refer to Table 24 to determine which steps apply to a particular engine.

Service Information

Gasket Leakage on Aftermarket Fuel Filters

There have been reports that some aftermarket fuel filters do not seal correctly on the 3400 series engines. The gasket projection on these fuel filters is insufficient for correct sealing. Do not replace the filter base for this problem.

Use only a Caterpillar fuel filter on Caterpillar engines to guarantee correct fuel filter performance.

Service Life of OEM Primary Filters

Some OEM's supply a disposable primary fuel filter for 3406 and 3406B truck engines in place of the Caterpillar primary filter. The mesh of the pleated paper used in these disposable filters is smaller than the screen mesh in the Caterpillar primary filter. As a result, the disposable primary filters have a shorter service life than the Caterpillar primary filter.

The smaller mesh of the disposable primary filter in a like new condition has not been known to cause excessive fuel transfer pump inlet restriction, or any other problem related to the fuel system. If questions arise, the inlet restriction can be checked. Check the restriction where the vehicle fuel supply line is connected to the engine. A new, clean primary filter must be used when checking the restriction. The filter is acceptable if the total inlet restriction is not more than 30.4 kPa (8.98 in mercury).

The frequency and severity of fuel waxing and plugging of the disposable primary filter will be similar for the final filter.

Shutoff Valve in Fuel Return Lines

Some truck manufacturers offer optional shutoff valve(s) in the fuel return line(s) at the fuel tank(s). If shutoff valves are used in the fuel return line circuit, at least one line must always remain open to the tank to allow return flow from all Caterpillar truck engines. The fuel must be allowed to return to the tank to cool the injectors and purge air from the system. If fuel is not allowed to return to the fuel tank, performance problems and/or unit injector damage may result.

In a dual fuel tank system (dual supply and return lines) a selector type valve which always allows return fuel flow to one of the tanks is permissible, provided there is an equalizer line connecting the two tanks. The preferred setting on the selector valve is for the return fuel to go to both tanks.

Fuel Heater Effects on Engine Performance

Only fuel heaters that have thermostats are self-regulated should be used on 3406B and 3406C truck engines with Programmable Electronic Engine Control (PEEC). Either the 7C-3557 Fuel Heater Gp or 7C-3558 Fuel System Parts Kit are recommended. Both heaters offer good protection against cold-weather fuel problems without the risk of overheating the fuel.

The temperature of the inlet fuel to the transfer pump on PEEC engines must not exceed 65.0° C (149.00° F). A higher fuel temperature reduces the life of the electronics and transfer pump check valves. Higher fuel temperature also reduces horsepower output. Fuel heaters that are not automatically controlled can head the fuel above 65.0° C (149.00° F).

The PEEC control module is cooled by fuel. The heat transferred to the fuel is not sufficient to eliminate the need for a heater in cold-weather operation. Fuel was selected to cool the unit because there is always flow during engine operation and fuel has a relatively low temperature. Fuel flows from the tank to the primary filter, through the transfer pump, through cored passages in the electronic control module housings to the secondary filter, and to the injection pumps.

Incorrect Use of Fuel Heaters Can Reduce Engine Power

3208, 3306, 3306B, 3306C, 3406, and 3406C. Truck Engines are designed for effective cold-weather operation, but the effectiveness of engine operation depends on many factors. Under certain conditions, an engine fuel heater may be needed to minimize cold-weather fuel problems such as plugged filters and fittings. If a fuel heater is needed, the 7C-3557 Fuel Heater Gp and 7C-3558 Fuel System Parts Kit are recommended. Both offer good protection against cold-weather fuel problems without the risk of overheating the fuel.

If a fuel heater from another manufacturer is used, some general guidelines should be followed to ensure maximum year-round engine performance. The fuel heater should be installed so the heater heats the fuel before the fuel flows through the primary (first) fuel filter. Select a fuel heater that is mechanically simple and adequate for the application. If a heat exchange type fuel heater is used, the heater should have a bypass provision to prevent overheating the fuel. If possible, disconnect or deactivate the fuel heater during warm-weather operation.

Overheating of fuel can result in a loss of engine horsepower. Fuel becomes less dense when heated, resulting in lower BTU content (heat) for the sale injected volume. Using a standard fuel temperature of 29.0° C (84.20° F) at the secondary fuel filter base, engine horsepower will decrease approximately 1% for every 5.6° C (10.08° F) increase in fuel temperature. An unregulated fuel heater used during warm-weather operation can often raise fuel temperature to more than 79.0° C (174.20° F). A fuel temperature of 79.0° C (174.20° F) could result in a horsepower loss of nearly 9% which would equal 27.0 kW (36.21 hp) for a 298.3 kW (400.00 hp) engine.

Fuel Flow Monitor System

The Caterpillar fuel flow monitor system for all Caterpillar truck engines if a versatile fuel flow measurement system to help evaluate engine performance. Refer to Tool Operating Manual, SEHS8874 for more information.

Some 3204 Engines with High Fuel Pressures

Table 25

Machines Experiencing High (Normal) Fuel Pressures
Model	Serial Number
D3C Track-Type Tractors	3RF507-UP, 6PF291-UP, 5KG1100-UP, 1PJ689-UP, 5CJ1-UP, 4HJ1-UP, 8DG1-UP, 7JG1-UP, 8BF211-UP
D4C Track-Type Tractors	1RJ903-UP, 2CJ355-UP, 7KG1-UP, 9BG1-UP
D5C Track-Type Tractors	6PJ1-UP, 3MK1-UP
931C Track Loaders (Powered by 3204 Engines)	7HF97-UP, 2BJ239-UP
935C Track Loaders (Powered by 3204 Engines)	8CF386-UP, 5DJ1-UP

"Higher than normal fuel pressure" is being reported on the 3204 Engines that power the machines listed in Table 25. A normal fuel pressure for other Caterpillar machines would be 205 to 345 kPa (30 to 50 psi), but the machines in Table 25. A have a higher normal fuel pressure of 410 to 550 kPa (60 to 80 psi) at engine high idle. This higher normal fuel pressure is acceptable on these machines.

Illustration 139	g06333702
Fuel transfer pump connections. (1) Fuel supply from filter. (2) Fuel injection pump housing. (3) 3N-7156 Hose Assembly (4) Fuel transfer pump.

The machines listed have the fuel filter located on the suction side of the transfer pump. These machines also have a 3N-7156 Hose Assembly between the fuel injection pump and the transfer pump, as shown in Illustration 139.

The suspected "higher than normal fuel pressure" is discovered during routine maintenance or while troubleshooting engine performance problems. Testing has shown that the higher fuel pressure does not cause other fuel system or engine performance problems on the affected machines. If an engine in one of the machines listed in Table 25 is experiencing performance problems, reducing the fuel pressure back to the 205 to 345 kPa (30 to 50 psi) range can actually delay finding the root cause of the performance problem.

Some 3304 Engines with High Fuel Pressures

This change applies to D4H (7PK, 2AC, 9DB, 8PB, 4NK, 9GJ, 3AC, 8ZF, and 8PJ) Tractors with 3304 Engines.

The fuel filter lines group has been changed to remove the steel tube between the fuel transfer pump and the fuel injection pump. A new hose assembly has been added in its place. The reason for this change is to eliminate high fuel transfer pump pressure caused by injection pump spill pulses. This high pressure is seen at high idle conditions and could cause fuel transfer pump damage. The new rubber hose reduces the pressure range to 410 to 550 kPa (60 to 80 psi). This transfer pump pressure is 205 to 345 kPa (30 to 50 psi) higher than other 3304 applications, but is an acceptable range on D4H Tractors.

Illustration 140	g06333730
103-1047 Hose Assembly. (1) 3J-1907 Seal (2) 030-7947 Elbow (3) 103-1047 Hose Assembly (4) Fuel transfer pump. (5) Fuel injection pump. (6) 9M-8406 Clip (7) 2B-0941 Spacer (8) 9M-1974 Washer (9) 1A-9579 Bolt

Installation Procedure

1. Install 3J-1907 Seal (1), 030-7947 Elbow (2), and 103-1047 Hose Assembly (3) from fuel injection pump (5) to fuel transfer pump (4).

2. Install a 3J-1907 Seal (1) and 030-7947 Elbow on fuel transfer pump (4).

3. Install 9M-8406 Clip (6), using 2B-0941 Spacer (7), 9M-1974 Washer (8), and 1A-9579 Bolt (9), as shown in Illustration 140.

Rebuild Kit for Fuel Transfer Pump

A 101-2614 Seal Kit is available to rebuild the 1W-0568 Fuel Transfer Pump Assembly used on 3204 Engines. The kit contains all the necessary seals and valve assemblies. Special Instruction, SEHS9414, "Fuel Transfer Pump and Spacer Replacement" describe the disassembly and assembly of the pump.

Using the Correct Nozzle

Table 26

Effective Serial Number Range	Original Nozzle Part Number	Service Nozzle Part Number	Reman Nozzle Part Number
3ZJ1-30053	7W-7041		0R-3587
3ZJ30054-36409	100-7550	100-7600	0R-4337
3ZJ36410-49796	100-7556	100-7600	0R-4337
425 hp at 1900 rpm
3ZJ49797-52109	100-7557	131-1243 (1), (2)	0R-8243 (1), (2)
3ZJ52110-Up	100-7557	131-1243 (1)	0R-8243 (1)
8PN1-5802	100-7567	127-9793	0R-8290
8PN5803-Up	127-9793	127-9793	0R-8290
400/375 hp at 1800 to 2000 rpm
3ZJ1-38057	7W-7042		0R-3588
3ZJ38058-Up	100-7557	131-1243	0R-8243
350/330 hp at 1600 to 1800 rpm
3ZJ1-16247	7W-7043		0R-3589
3ZJ16248-31974	7W-7040		0R-3586
3ZJ31975-38395	100-7551	100-7551	0R-4335
3ZJ38396-52023	100-7558	100-7551 (3)	0R-4335 (3)
350 hp at 1950 rpm
3ZJ1-16241	7W-7043	7W-7043	0R-3589
3ZJ16242-34762	7W-7040	7W-7040	0R-3586
3ZJ34763-38395	100-7551	100-7551	0R-4335
3ZJ38396-52023	100-7558	100-7551 (3)	0R-4335 (3)
350 hp at 1800 rpm
3ZJ52024-Up	100-7558	131-1242	0R-8242
400 hp at 1900 rpm
8PN1-5985	121-4353	127-9792	0R-8289
8PN5986-Up	127-9792	127-9792	0R-8289
320/285 hp at 1600 to 1800 rpm
3ZJ1-37234	7W-7040	7W-7040	0R-3586
3ZJ37235-Up	100-7558	100-7558	0R-4339

(1)	Exception is 2T-6451 Brakesaver Engines. Service with 100-7557 (0R-4338) Nozzles
(2)	Only applies to 2T-6216 and 2T-6217 Performance Specifications
(3)	100-7551 and 0R-4335 can only be used for servicing this serial number range if the corresponding timing advance unit (TAU) changes are made as per Table 27.

Table 27

Changes Required to Use 100-7551 and 0R-4335Nozzle Assemblies in 350 hp 3406C Truck Engines 3ZJ38396 to 52023 (Mechanical Only)
Description	Engines Rated at 350 hp at 1800 rpm	Engines Rated at 350 hp at 1950 rpm
Fuel Nozzle	Install six 0R-4335 Nozzle Assemblies	Install six 0R-4335 Nozzle Assemblies
Timing Advance Unit (TAU) Spring	N/A	Install CODE C TAU Spring (6 I -3061)
Reset Timing Advance Schedule	From: 1520 Start, 1705 Stop, 4.0 Degrees To: 1450 Start, 1856 Stop, 9.1 Degrees	From: 1630 Start. 2040 Stop, 9.5 Degrees To: 1410 Start, 1970 Stop, 9.6 Degrees
Reset FRC Setting	N/A	From: −.60 to −.80 mm (−0.02362 to −0.03150 inch)
4W-5140 Engine Information Plate	Install new plate and stamp CODE B Test Specification and CODE B FRC Setting	Install new plate and stamp CODE C Test Specification and CODE C FRC Setting
Order New EPA Sticker	Install new EPA Sticker (CODE B)	Install new EPA Sticker (CODE C)

Fuel Injection Nozzles

New fuel injection nozzles are used to help reduce white exhaust smoke that may occur during a cold engine startup. The new fuel injection nozzles have a lower valve opening pressure 22737 kPa (3297.77448 psi) versus the former 25665 kPa (3722.45160 psi). Testing has shown that a lower valve opening pressure will help reduce white exhaust smoke from a cold engine.

The new 127-9793 Nozzle Assembly is a direct replacement for the former 100-7567 Nozzle Assembly used in 425 hp 3406C (8PN) Truck Engines. The new 127-9792 Nozzle Assembly is a direct replacement for the former 121-4353 Nozzle Assembly used in 350 hp 3406C (8PN) Truck Engines

Internal Seals

Internal seals in 7000 series fuel injection nozzles cannot be replaced. Current parts book and microfiche for 3406B Engines list two internal seals as part of the 7000 Series Fuel Nozzles. As stated in the service manuals, the fuel nozzle should not be disassembled or adjusted. Only the bleed screw seal is serviceable. Do not attempt to replace the internal nozzle seals.

Nozzle Seals

Note: Replacing internal nozzle seals can result in incorrectly assembled fuel nozzles, causing possible engine damage.

Illustration 141	g06334911
Identifying fuel injection nozzles. (A) Part number (B) Date code (1) Upper adapter seal (2) 114-3364 Bleed Screw Seal (3) Lower body seal

Effective with 7000 Series Fuel Injection Nozzles on 3204, 3300, 3406, and 3408 Engines with date code "05A94" and later, is the use of a new seal material in three locations. New seal material has better heat set resistance. Location (1), Illustration 141) is the upper adapter seal. Location (2) is the 114-3364 Bleed Screw Seal. Location (3) is the lower body seal. Only the 1 114-3364 Bleed Screw Seal (2) is serviced.

Added Durability and Performance

Manufacturing and design improvements have been made on the 7W-7038, 7W-7045, 8N-7005, 100-7563, and 100-7564 Nozzle Assemblies. These changes improve the durability and performance and helps prevent cracking.

The improvements are effective on fuel injection nozzle assemblies manufactured on or after February 24, 1997 (nozzle date code of 24B97 or later). These fuel injection nozzle assemblies are used in Caterpillar machines powered by 3304 (07Z3498-Up) and 3306 (08Z97573-Up or 13Z39437-Up) Engines.

Bleed Screw

The bleed screw on 7000 Series Fuel Injection Nozzles used in 3200 Engines uses a line head screw. The bleed screw allows a more consistent torque capability which will result in better sealing. A 1U-5895 Bit, part of 6V-4980 Tool Group, is required to remove and install the new bleed screw.

If a bleed screw is damaged or lost, replace it with an 8C-3234 Screw (line head socket head). The installation torque of the 8C-3234 Screw is 2.2 ± 0.8 N·m (19.47165 ± 7.08060 lb in).

Through-Head-Adapter O-Ring Seals

Illustration 142	g06334923
Location of new 132-2072 O-ring Seal (1) and 8L-2779 O-Ring Seal (2) in a typical fuel injection lines group.

New O-ring seals (1) and (2) are used on the "through-head-adapters" (B) and "internal fuel lines" (C) in the fuel injection lines groups on machines powered by 3406 (11N15840-Up) and 3406C (41Z2419-Up) Engines. The new O-ring seals have increased resistance to heat damage.

The new 132-2072 O-ring Seal (1)) is a direct replacement for the former 8M-4437 O-Ring Seal on "through-head-adapters" (B) and the new 8L-2779 O-Ring Seal is a direct replacement for the former 1H-1023 O-Ring Seal on "internal fuel lines" (C) in the fuel injection lines groups on these engines.

The new O-ring seals can be used to replace the former O-ring seals on all earlier 3406 and 3406C Engines in Caterpillar machines

Fuel Line and Adapter Assemblies

The former adapter assembly was held in position in the head with an adapter lock. The adapter lock could wear and loosen, allowing the adapter to move in the head. This could result in wear on the O-ring seal between the adapter assembly and head. A worn O-ring seal could allow oil to leak out of the head at the adapter assembly. The lock is now part of the new adapter assembly so it will not loosen and allow movement of the adapter. This will help prevent O-ring wear which can result in oil leaks. These parts are used in 3406B and 3406C (6TB, 2WB, 4RG, 4TB, 3ZJ, 5KJ, 8PN, 8TC, 2EK, and 4CK) Engines.

The new fuel line assemblies are stronger than the former fuel line assemblies and will provide increased service life.

Table 28

Engine Model	New Fuel Line Assembly Effective With	New Adapter Assembly Effective With
Generator Set	2WB10808 4RG1324	2WB11355 4RG1443
Industrial	6TB8990	6TB9546
Marine	4TB3262	4TB3431
Truck	3ZJ8026 5KJ7616 ZEK1268 4CK197	3ZJ20261 5KJ7864 ZEK1960 4CK1573

Illustration 143	g06335007
Location of new components. (1) 4P-1396 Adapter Assembly (2) O-ring seal (3) 4P-9661 Line Assembly (4) 4P-9662 Line Assembly (5) 4P-9663 Line Assembly (6) 4P-9664 Line Assembly (7) 4P-9665 Line Assembly (8) 4P-9666 Line Assembly

The new 4P-1396 Adapter Assembly replaces the former 4P-1797 Adapter Assembly and 4N-1292 Adapter Lock. Each new adapter assembly includes a new 4P-1393 Adapter Assembly (not serviced separately) and O-ring seal. The new 4P-1393 Adapter Assembly is in effect as shown in Table 28. The former adapter assembly and adapter lock are not canceled.

Note: If a former adapter assembly and adapter lock are replaced with a new adapter assembly, the former fuel line assembly must be replaced with a new fuel line assembly. A new fuel line assembly can be used with a former adapter assembly, but a former fuel line assembly should NOT be used with a new adapter assembly.

The new 4P-9661 through 4P-9666 Line Assemblies are direct replacements for the former line assemblies which are canceled. The new line assemblies are in effect as shown in Table 28.

Fuel Line Support Brackets

Illustration 144	g06335213
Typical side view of a 3406 Engine showing brackets, bracket assemblies, and related hardware.

Table 29

Model Information
D8N (8WC, 9TC, 1XJ, 5TJ, 7TK), D8R (7XM) Track-Type Tractors
D40D (2JJ), D350E (9LR), D400 (1MD), D400D (4EJ), D400E (2YR) Articulated Trucks
RR-250 (6ED), RR-250B (3RR) RRSS Road Reclaimers
SS-250 (6DD), SS-250B (5GR) RRSS Soil Stabilizers
RM-350 (5FK), RM-350B (7FS) RRSS Reclaimer Mixers
SM-350 (1RM) RRSS Stabilizer Mixers
16G (93U), 16H (6ZJ) Motor Graders
245 (94L, 95V, 82X,84X), 245B (6MF, 1SJ), 245D (7ZJ, 4LK), 375 (8XG, 8WJ, 6NK), 375L (6RL, 9WL, 1JM) Excavators
578 (8HB) Pipe Layers
621E (6AB, 2PD), 621F (4SK, 8PL), 623E (6YF), 623F (6BK), 627F (1DL), 825C (85X), 824G (4SN) Wheel Tractors
825C (86X), 825G (6RN), 826C (87X), 826G (7LN) Compactors
980C (13B, 2EB, 2XD, 63X), 980F (5XJ, 8CJ, 3HK, 4RN, 8JN), 980G (9CM, 2KR, 2SR) Wheel Loaders
5080 (6XK, 8SL) Front Shovels Powered By 3406, 3406B (11N15976-Up), and (41Z5850-Up) Engines With The New Scroll Fuel System (NSFS)

Table 30

Bracket, Bracket Assemblies, and Related Hardware
Item	Quantity	Part Number	Description
1	N/A	N/A	Fuel Line Number One
2	N/A	N/A	Fuel Line Number Two
3	2	4B-2047	Nut
4	4	6V-7699	Hard Washer
5	4	1W-9168	Clamp
6	2	1W-9167	Fuel Line Clamp Assembly
7	2	7M-9831	Screw
8	2	104-3038	Screw
9	2	4B-4274	Washer
10	N/A	N/A	Fuel Line Number Four
11	N/A	N/A	Fuel Line Number Three
12	2	144-3517	Clamp
13	2	1W-9169	Clamp
14	N/A	N/A	Fuel Line Number Six
15	N/A	N/A	Fuel Line Number Five
16	2	7M-9910	Screw
17	1	141-2675	Bracket Assembly
18	1	141-2676	Bracket Assembly
19	1	141-2674	Bracket
20	1	9M-1974	Washer
21	1	0S-1617	Bolt
22	1	141-2672	Bracket

Support brackets (19) and (22), Illustration 144), bracket assemblies (17) and (18), and related hardware help eliminate problems with vibration of fuel lines. The 141-2672, 141-2674, 141-2675, and 141-2676 brackets and bracket assemblies are used in the machines listed in Table 29 or powered by 3406 and 3406B (11N15976-Up) or 3406C (41Z5850-Up) Engines with NSFS. These parts are a direct replacement for the former parts.

Refer to Table 30 and Illustration 144 for the location and part numbers on a typical engine. This change is adaptable to first production of 3406, 3406B, and 3406C Engines with NSFS.

Note: Parts not identified in Illustration 144 did not change and can be reused with the new brackets.

Procedures

Electronic Timing Advance

Illustration 145	g06334373
Timing control group components. (1) Solenoid (2) Control Group (3) Bellcrank Assembly (4) Pin

Illustration 146	g06334375
Timing control group components. (3) Bellcrank Assembly (4) Pin

1. Check BTM solenoid (1), Illustration 145) arm.

   1. Check arm to shaft joint for damage

   2. Check the solenoid part number. The former 9X-6770 Solenoid has been replaced by the new 105-2939 Solenoid. The new solenoid has a stronger shaft and is effective with 4CK2537.

2. Check control group (2), Illustration 145) timing sensor for a loose tip.

   1. Check for loose tip.

   2. Put 9S-3263 Thread Lock on the threads of the 9X-9555 Control Group (timing sensor) before it is installed. This change is effective with serial number 4CK6001.

   3. The 118-7204 Sensor Tip Kit is available for repairing or replacing the sensor tip.
   Show/hide table

   Illustration 147	g06334383
   Governor and fuel pump drive group components. (5) 2W-3635 Sleeve (6) Thrust bearing (7) 4P-3384 Spool (8) 6J-2819 Bolts (9) 108-4511 Clamp Assembly (10) 101-1942 Plug in 101-1944 Carrier Assembly

3. Make sure that the bellcrank is in the correct position. Refer to (3), Illustrations 145 and 146) and (5), (6), Illustration 147). Check the thrust bearing face and the front of the 2W-3635 Sleeve for wear caused by the bellcrank being out of position with respect to the thrust bearing.

4. Check bellcrank assembly to be sure pin (4), Illustrations 145 and 146) is correctly installed.

   1. Check the faces of the bellcrank for excessive wear.

   2. Check the round area of the bellcrank to be sure that the spring is not causing galling of the bellcrank on the pivot pin.

   3. The 2W-3623 Bellcrank Assembly pin depth is correct effective with serial number 4CK11473.

   4. Bellcrank end play should be 0.13 to 0.64 mm (0.00512 to 0.02520 inch).

5. Check spool (7), Illustration 147) in fuel pump and governor drive group.

   1. Check spool for damage and part number.

6. Replace former 4W-2750or 7E-5564 Spool with new 4P-3384 Spool. The new spool is effective with serial number 8TC13234.

7. Check eight bolts (8), Illustration 147) in fuel pump and governor drive group.

   1. Make sure 6J-2819 Bolts (8) are used.

   2. Tighten the 6J-2819 Bolts to 16 N·m (12 lb ft). The new longer bolts and higher tightening torque are effective with serial number 2EK1823.

8. Check to be sure that the former 3P-3547 Retaining Ring has been replaced by the new 108-4511 Clamp Assembly (9), Illustration 147).

9. Check to be sure the plug (10), Illustration 147) is in position in the carrier assembly. Refer to callout (10). (New threaded plug used with 101-1944 Carrier Assembly, as shown).

   1. New 101-1944 Carrier Assembly with threaded plug effective with serial number 4CK4699.

   2. Do NOT use former 0T-0200 Cup Plug.
   Show/hide table

   Illustration 148	g06334422
   Governor and fuel injection pump group. (11) 8S-4710 Bolt

10. Check for oil leakage between governor and fuel injection pump housing (X), Illustration 148.

    1. Oil leaks can be internal or external.

    2. Check for oil leaking past 4W-2491 Gasket.

    3. The new tightening specifications for 8S-4710 Bolt (11) is 16 ± 4 N·m (12 ± 3 lb ft) and is effective with serial number 4CK15840.

Mechanical Timing Advance Drive

Table 31

Truck Governor Drive Groups 88 and Newer
Governor Drive Groups	Spring Part Numbers	Effective Serial Numbers	Rating	Model Years
9Y-1772	9Y-1771	4MG3600	285-310 CARB	88
9Y-1838	9Y-1837	4MG3600	285-310 EPA	88-89
4W-8334	4W-8332	4MG3600	350 CARB	88
7C-0841	7C-6622	4MG3600	350 EPA	88
9Y-1545	4W-8335	4MG3600	40088
4W-8333	7C-9219	4MG3600	425 @ 2100	88
7E-1040	9Y-5881	4MG43578 (1)	285-310 CARB	89-90
7E-1041	9Y-5882	4MG43578 (1)	350 CARB	89-90
7E-1039	9Y-5736	4MG43578 (1)	350 EPA	89
7E-1042	9Y-5883	4MG43578 (1)	370-400	89-90
7E-1043	9Y-5884	4MG43578 (1)	425	89-90
9Y-5395	4P-8249	3ZJ3844 (2)	285-310	91
4P-1408	4P-8244	3ZJ3827 (2)	330 @ 1600	91
4P-1403	4P-8243	3ZJ3928 (2)	330 @ 1800	91
4P-1922	4P-8245	3ZJ3928 (2)	350 @ 1800	91
4P-1401	4P-8246	3ZJ3838 (2)	350 @ 2000	91
4P-1923	4P-8250	3ZJ3837 (2)	375	91-93
4P-1925	4P-8248	3ZJ3830 (2)	425 Standard Torque	1-93
4P-1409	4P-8247	3ZJ3829 (2)	425 High Torque	91-93
6I-3059	4W-8012	3ZJ1618 (2)	285-330 @ 1600	92-93
6I-3057	6I-3056	3ZJ1618 (2)	330 @ 1800	92-93
6I-3055	6I-3054	3ZJ1618 (2)	350 @ 1800	92-93
6I-3062	6I-3061	3ZJ1618 (2)	350 @ 1950	92-93
113-8213	113-8212	3ZJ52110	400 @ 2000	94-96
116-4208	113-8212	3ZJ52110	425 @ 1900	94-96
122-1628	6I-3054	8PN1	350 @ 1800	95-96
122-5964	6I-3054	8PN1	400 @ 1900	95-96
117-7224	4P-8247	8PN1	425 HT @ 1900	95-96

(1)	5KJ serial numbers were used in the third and fourth quarters of 1990. Refer to text for the description of changes.
(2)	Effective serial numbers of the governor drive groups with new heat set springs. The drive group effective serial number is 3ZJ1.

Changes to the timing advance drive groups are for mechanical governed 3406B/C (4MG, 3ZJ, 5KJ, and 8PN) Truck Engines and 3406 NSFS Engines. Then changes are listed in chronological engine serial number order.

Production Serial Numbers

4MG3600

Released new style timing advance with a cone shaped cover. When compared with the former timing advance, this timing advance provides increased advance capacity (up to 12.5 degrees). The new drive group part numbers are shown in Table 31.

4MG18385

The change provides a new 9Y-7450 Retainer (flyweight pin) with a different material and heat treatment. The new retainer will service the previous retainer to first production of the new style timing advance (4MG3600).

4MG25122

This change provides an 8L-5832 Hex Nut (full width) in place of the former half nut. The new lock nut will service the former lock nut to first production of the new style time advance (4MG3600).

4MG57674

This change provides two new 7E-2460 Races (top hat shaped) to replace the previous single bearing race. This change also provides a new high strength 009-3101 Ring. These changes significantly improve flyweight and race life. These new components will service the former bearing race and ring to first production of the new style timing advance (4MG3600).

4MG97295

This change provides a new 7E-8097 Carrier Assembly that eliminates body-carrier slip. The preferred service method is to replace the former 7W-5242 Drive Carrier, 7C-5902 Body Assembly, 8F-1145 Lock Ring, and 4W-2754 Lobed Seal with the new 7E-8097 Carrier Assembly back to first production of the new style timing advance (4MG3600).

5KJ465

This change provides eight mounting bolts instead of the former four for increased clamping and reduced slippage. The carrier assembly is changed to accommodate a larger 52 tooth spline. Both of these changes are needed for the 1991 emissions fuel system configuration. These changes are not adaptable to earlier engines. The components involved with this change include the 4P-2921 Guide Ring, 4P-2644 Carrier Assembly, 9X-7715 Lobed Seal, 4P-2920 Flyweight Cover, 4P-2922 Plate, 4P-2924 Drive Ring, and 0T-0065 Bolt.

5KJ2681

This change provides a new wider flyweight toe and race for improved resistance to wear and increased overall durability. The components involved in this change include the 4P-7693 Weight Carrier, four 4P-1634 Governor Weights, 4P-1638 Adjustment Screw, two 4P-1635 Flyweight Races, 4P-1637 Advance Spool, and 4P-3337 Flyweight Race. These components are required to service back to first production of the new style timing advance (4MG3600). This change was released with the 4P-1636 Weight Carrier, which was canceled and replaced by the 4P-7693 Weight Carrier.

Table 32

Drive Groups and Corresponding New Springs
Part Number	Effective	Serial Number
4P-1408	4P-8244	3ZJ3827
4P-1909	4P-8247	3ZJ3829
4P-1925	4P-8248	3ZJ3830
4P-1922	4P-8245	3ZJ3826
4P-1401	4P-8246	3ZJ3838
9Y-5395	4P-8249	3ZJ3844
4P-1043	4P-8243	3ZJ3928

3ZJ

This change provides a new "heat set" springs that do not change load characteristics over time when exposed to engine heat. These new springs will help better maintain factory timing advance settings. Refer to the list of Drive Groups and their corresponding new springs in Table 32.

3ZJ1

This change provides a new 4P-7693 Weight Carrier to replace the former 4P-1636 Weight Carrier. This change will service back to first production of the new style timing advance (4MG3600). The part numbers of the new drive groups are shown in Table 31.

3ZJ911

This change provides a new thicker leg flyweight, race, carrier assembly, and spool. This change will help reduce the chance of flyweights binding or breaking. The carrier no longer has the acceleration noise control orifice. The components involved with this change are the 4P-7693 Weight Carrier, 4P-7692 Governor Weight, 4P-7690 Flyweight Race, 4P-7691 Advance Spool, and 4P-2641 Carrier Assembly. Those components are required to service back to first production of 3ZJ1.

8PN10878

This change provides a new 119-2130 Governor Weight which is a service replacement for 4P-7692 Governor Weight. The governor weight toe hard coating has a new edge process to reduce chipping. This weight is serviceable back to 3ZJ911 and 8PN1.

8PN11384

This change provides a new 132-7444 Weight Carrier for the flyweights. The new weight carrier is a service replacement for the former 107-6770 Weight Carrier. The new weight carrier provides eight bolts, instead of the previous four. This change further reduces the possibility of joint slip by doubling the amount of bolt camp force. The new weight carrier attaches to a new 132-7446 Carrier Assembly, which provides eight threaded holes. The 132-7446 Carrier Assembly replaces the former 4P-2641 Carrier Assembly and is serviceable back to 3ZJ1, 5KJ1, and 8PN1 by using four of the eight mounting bolt holes. The 132-7446 Carrier Assembly is serviceable back to 3ZJ1 and 8PN1.

Electronic Timing Advance Drive

8TC1

This change provides the 2W-4544 Drive Group for the 8TC engine introduction.

8TC---(Unknown)

This change provides the new 7W-0993 Drive Gear with improved material quality. This change will service the former drive gear back to 8TC1.

8TC---(Unknown)

This change provides the new 7W-3218 Ring (Quadseal) with improved material quality.  This change will service the former ring back 8TC1.

8TC---(Unknown)

This change provides the new 3P-3547 Clip (used to retain the brushless torque motor sleeve assembly on the spool). This change will service the former clip back to 8TC1. (Also refer to the 4CK15345 improvement).

8TC8730

This change provides the new stronger 7E-5564 Spool. This change will service the former spool back to 8TC1. (Also refer to the 8TC13234 and 5YG1 improvements.)

8TC12973

This change provides a new 7E-9060 Carrier Assembly which eliminates body-carrier slip. The preferred service method is to service the 2W-7986 Body Assembly, 8F-1145 Ring, 1W-4329 Carrier, and 4W-2754 Seal, with the new 7E-9060 Carrier Assembly.

8TC13234 and 5YG1

This change provides the new 4P-2648 Drive Group for use on the 5YG engine. This release also provides the new 4P-3500 Sleeve Assembly and 4P-3384 Spool with improved material properties for the 2W-4544 (8TC1) and 4P-2648 (5YG1) Drive Groups. The new sleeve assembly and spool will service back to 8TC1. The 4P-2648 Drive Group is like the previously built 2W-4544 Drive Group, except for the new 4P-3500 Sleeve Assembly and 4P-3384 Spool.

8TC13823

This change to the 2W-4544 Drive Group provides eight mounting bolts, instead of the former four, for increased clamping and reduced slippage. The carrier assembly is changed to accommodate a larger 52 tooth spline. These changes are not adaptable to earlier 8TC engines or any 5YG engines. This change occurred at the end of the 5YG serial number prefix. The components involved with this change include the 4P-2921 Ring, 4P-2642 Carrier, 9X-7715 Seal, 4P-2922 Plate, 4P-2923 Ring, and eight 0T-0065 Bolts.

2EK1823 and 4CK993

This change provides the new longer 6J-2819 Bolt for improved torque retention. The new bolt will service back to 8TC1.

4CK4699

This change provides the new 101-1944 Carrier Assembly. This new carrier assembly has a threaded plug to reduce the chance of the plug coming out. The new carrier assembly will service back to 8TC13823.

4CK15345

This change provides the new split clamp design to replace the previous 3P-3547 Clip. These parts are used to retain the brushless torque motor sleeve assembly on the spool. The new 108-4511 Split Clamp Group will service back to 8TC1. Also included in these changes are two 107-2961 Washers for better wear and durability with the sleeve assembly. These washers also service back to 8TC1.

New Dynamic Fuel Ratio Control Settings Provide Improved Engine Response

Table 33

Dynamic Fuel Ratio Control Settings
Engine Serial Number	Dynamic Rack	Static Level	FRC Part Number
7RJ1-2750	-3.2	-1.9	4P-2507
7RJ2751-Up	-2.8	-1.5	4P-2507
9TL1-3439	-2.26	-2.56	107-5580
9TL3440-Up	-2.1	-2.4	119-3843

The dynamic Fuel Ratio Control (FRC) setting on 3306C (7RJ, 9TL) Truck Engines can be reset if low power or poor response from the engine has occurred. Table 33 and the procedure are used to check the dynamic Fuel Ratio Control (FRC) and, if necessary, to reset the FRC setting.

Use the following procedure for checking the dynamic FRC setting.

1. Remove the Fuel Ratio Control (FRC).

2. Install an 8T-3100 Position Indicator or rack gauge.

3. Energize the shutdown solenoid (or remove it).

4. Zero the rack reading.

5. Install the FRC and the shutdown solenoid (if it was removed).

6. Do not connect the boost line to the FRC.

7. Accelerate the engine to the "Full Throttle" position and record the dynamic rack reading.

8. If the rack reading is not within specifications, adjust the screw on the end of the FRC stem.

9. Connect the boost line to the FRC.

Snap Idle Test

1. From low idle, rapidly move the governor control shaft to the full FUEL ON position and read the measurement on the dial indicator. Read the indicator carefully because this reading will be at a maximum reading for only a moment. Make a record of the maximum dial indicator reading. If full measurement is not reached, increase the air pressure to make sure that there is full fuel ratio control movement.

   Note: The fuel ratio is activated and the maximum dial indicator reading is the dynamic full torque setting of the engine. This setting is 0.5 mm (0.01969 inch) greater than the static full torque setting given on the Engine Information Plate of later engines or in the Fuel Setting and Related Information Fiche.

   Note: On engines where the fuel ratio control is out of adjustment, the fuel ratio control can activate shortly after engine startup. Currently the dial indicator reading can be the dynamic fuel ratio control setting. Continue the checking procedure to find the dynamic full torque setting at Step 5.

2. Release all air pressure from the fuel ratio control. Start at 900 rpm and rapidly move the governor control shaft to the full FUEL ON position and read the measurement on the dial indicator. Read the dial indicator carefully because this reading will be at a maximum reading for only a moment. Make a record of this dial indicator reading. This is the dynamic fuel ratio control setting for the engine.

3. If the dynamic fuel ratio setting is within 0.25 mm (0.00984 inch) of the specifications on the Engine Information Plate or in the Fuel Setting and Related Information Fiche, an adjustment is not necessary.

4. For adjustment of the control, refer to the Fuel Ratio Control Adjustment, following this procedure.

5. Check boost pressure that gives full torque rack travel, as follows:

   1. Connect a pressure gauge, a pressure regulator, and an air supply to the fitting from which the air line was removed.

   2. Apply 25 kPa (3.62600 psi) air pressure to the fuel ratio control.

   3. Start at 900 rpm and rapidly move the governor control shaft to the full FUEL ON position and make a record of the maximum dial indicator reading.

   4. Repeat this procedure several times, each time increase the air pressure 5 kPa (0.72520 psi).

   5. Make a record of the first air pressure setting that gives full torque rack travel. Full torque rack travel was measured in Step 1.

Fuel Ratio Control Adjustment

Table 34

Tools Needed
Part Number	Description	Quantity
2W-9161	Manual Shutoff Group	1
6V-4186	Timing Pin	1
6V-6070	Governor Adjusting Tool Group	1

Note: Before the governor seals are cut or removed, refer to Fuel Ratio Control and Governor Check, in the appropriate Service Manual, to make sure that an adjustment is needed.

Illustration 149	g06334850
Earlier fuel ratio control. (1) Nut (2) Retainer (3) Stop (4) Nut (5) Extension

Note: On earlier engines, Step 4 must be done to make sure that stop (3) does not contact retainer (2). Later engines do not have stop (3) and nut (4). Do not add these parts when the fuel ratio control is repaired.

Illustration 150	g06334860
Later fuel ratio control (1) Nut (5) Extension

1. Refer to the Engine Information Plate or the Fuel Setting and Related Information Fiche for the correct dynamic fuel ratio control setting specification before an adjustment is made.

2. Install and zero the rack position indicator group. Refer to Fuel Ratio Control and Governor Check for this procedure.

3. Remove the cover from the fuel ratio control valve

4. Loosen nut (4) and turn stop (3) in (clockwise) until the stop makes contact with the shoulder on retainer (2). Now turn the stop out (counterclockwise) two complete turns and tighten nut (4).

5. Start the engine and operate it for a minimum of five minutes to get the governor and engine up to normal operating temperature.

6. Activate the fuel ratio control by pushing in on valve extension (5).

7. Hold retainer in position and loosen nut (1). This keeps the fuel ratio diaphragm from turning when nut (1) is loosened or tightened.

8. Turn valve extension (5) to get the correct setting. A clockwise direction will give a more positive setting. The counterclockwise direction will give a more negative setting. Several adjustments of valve extension (5) may be needed to get the correct dynamic fuel ratio control setting.

9. After each adjustment is made, check the dynamic fuel ratio control setting. Start at 900 rpm and rapidly move the governor control shaft to the full FUEL ON position and read the measurement on the dial indicator. Read the dial indicator carefully because this reading will be at a maximum reading for only a moment. Make a record of the maximum dial indicator reading.

   Note: If the correct dynamic fuel ratio control setting cannot be made with this adjustment, the internal governor linkage must be checked and adjusted or the fuel ratio control needs repair or replacement. Refer to Check and Adjustment of the Fuel Ratio Control Linkage, in the Service Manual, for the governor linkage procedure.

10. After the correct adjustment has been made, tighten nut (1). Check the dynamic fuel ratio control setting again.

11. Install the gasket and cover on the fuel ratio control. Tighten the bolts to a torque of 9 ± 3 N·m (6.63804 ± 2.21268 lb ft).

12. Apply 70 kPa (10.15280 psi) air pressure to the fuel ratio control at the fitting. This will fully extend the fuel ratio control to get dynamic full torque.

13. Check the dynamic full torque setting. Start at 900 rpm and rapidly move the governor control shaft to the full FUEL ON position and read the maximum measurement on the dial indicator

FRC Air Pressure Test

Table 35

Tools Needed
Part Number	Description	Quantity
2W-9161	Manual Shutoff Group	1
6V-4186	Timing Pin	1
6V-6070	Governor Adjusting Tool Group	1
FT-1906	Air Test Kit	1
6V-4060	Engine Set Point Indicator Group or Circuit Testing Flashlight	1
6V-9128	Rack Position Tool Group	1
4N-5656	Cover	1

Note: The governor seals do not have to be cut or removed for the checking procedures that follow. For more information on the tooling and procedures, refer to Special Instruction, SEHS8463, "Fuel System and Fuel Ratio Control Test Procedure".

1. Install the rack position indicator to measure fuel rack movement. Refer to Steps 1 through 4 in the Fuel Setting Procedure of the Service Manual for the correct installation of the tooling.

2. Turn the engine start key ON to activate the shutoff solenoid. Do not start the engine at this time.

3. Move the governor control linkage to the full FUEL ON position and hold or fasten it in this position.

4. Install the 6V-4186 Timing Pin in the rack zeroing hole in the pump housing.

5. With the governor control lever in the FUEL OFF position, use a 1N-9954 Lever and move the manual shutoff shaft slowly to the FUEL OFF position (counterclockwise). Watch and make sure the timing pin drops and engages with the slot in the fuel rack.

6. Release the manual shutoff shaft and zero the dial indicator. Move the dial indicator in the collet to zero and tighten the collet. Make sure that all three needles of the indicator are on zero.

7. Remove the 6V-4186 Timing Pin and watch the dial indicator movement. The indicator should show movement in the FUEL ON direction. If no movement occurs, repeat Steps 4, 5, and 6 to zero the indicator.

8. Release the governor control shaft and linkage.
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   Illustration 151	g06334872

9. Remove the air line (3) from the engine. Put plugs over the opening to keep dirt out of the system.

10. Start the engine and operate it for a minimum of five minutes to get the governor and engine up to normal operating temperatures
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    Illustration 152	g06334873
    FT-1906 Air Test Kit (1) 8L-6557 Connector (2) 5P-4405 Connector (two required) (3) 5P-6011 Tube (4) 5P-4476 Connector (5) 6K-5741 Valve (6) 5P-4459 Elbow (7) 7B-0192 Cross (8) 3B-6768 Bushing (9) 6V-7775 Gauge (10) 6N-3169 Hose Assembly (11) 6V-6757 Elbow (12) 6.35 mm (0.25000 inch) I.D. Flexible Tubing 1.2 m (4 ft) (13) Air pressure bulb (Baumamometer No. 1890 or equivalent)

11. Check the leak down rate of the fuel ratio control (with the engine operating at low idle) as follows:

    1. Connect a pressure gauge, a shutoff valve, a pressure regulator, and an air supply to the fitting from which the air line was removed.

    2. Apply 70 kPa (10.15280 psi) air pressure to the fuel ratio control.

    3. Turn the shutoff valve OFF and check the leak down rate. Leakage of 20 kPa (2.90080 psi) is 30 seconds is acceptable.

    4. If leakage is more than 20 kPa (2.90080 psi) in 30 seconds, the fuel ratio control must be repaired

Installing a Check Valve

The following parts are required to install a 138.00 kPa (20 psi) check valve on the outlet of the sight glass on the 4C-9759 Return Flowmeter Group (Small) and the 4C-9761 Return Flowmeter Group (Large).

Illustration 153	g06322012
(1) Return Flowmeter Group (2) Check Valve (3) Primary Air Filter (4) Supply Fuel Flowmeter Group (5) Fuel Transfer Pump (6) Fuel Filter (7) Fuel Supply Line (8) Fuel Injection Pump (9) Fuel Return Line (10) Diesel Fuel Tank

Table 36

Parts Required for 4C-9759 Return Flowmeter Group (Small)
Part Number	Description	Supplier
C820S-20	Check Valve	Parker Hannifin
6402-0808-0	Female Fitting (No. 8 JIC)	Airway
RAC-1000-8	Male fitting (No. 8 JIC) on the outlet of the sight glass	Flowdar

Table 37

Parts Required for 4C-9761 Return Flowmeter Group (Large)
Part Number	Description	Supplier
C820S-20	Check Valve	Parker Hannifin
6402-1616-0	Female Fitting (No. 16 JIC)	Airway
RAC-1000-16	Male fitting (No. 16 JIC) on the outlet of the sight glass	Flowdar

Install a Replacement Fuel Injection Pump

1. Rotate the fuel pump camshaft so the replacement fuel injection pump will be installed on the base circle, not on the lobe of the fuel pump camshaft.

2. Remove or activate the shutoff solenoid.

   Note: To check the installation of a replacement pump, it is necessary to have full rack travel in both directions. Use the following steps (as needed) to position the pump and have full rack travel in both directions. The actual zero location of the timing pin and rack is not used to check the installation of replacement pumps.

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   Illustration 154	g06322312
   Fuel rack and timing pin.

3. Remove the cover (rack position indicator) and plug (rack centering pin) and install the 6V-4186 Timing Pin as shown in Illustration 154.

4. Raise the timing pin and move the rack to the full load position. Use finger pressure to be sure that the rack is at full rack travel (beyond full load position).
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   Illustration 155	g06322313
   Correct installation in full load position.

5. If the fuel injection pump installation is correct, when the timing pin is lowered it will be on the rack as shown in Illustration 155.
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   Illustration 156	g06322317
   Incorrect installation, full load position restricted by less than full rack travel. (A) 1.91 mm (0.07520 inch) per tooth

6. If the fuel injection pump installation is NOT correct, the timing pin position will be approximately 1.91 mm (0.07520 inch) toward the slot for each tooth position out of alignment (refer to Illustration 156). This will reduce fuel rack travel, even though it may not affect the rack setting, because of additional rack travel at static conditions.

7. Raise the timing pin and move the rack to the no load (fuel off) position.
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   Illustration 157	g06322313
   Correct installation at no load (fuel off) position.

8. If the fuel injection pump installation is correct, when the timing pin is lowered it will be in the timing slot, less than 1.91 mm (0.07520 inch) from the rear face of the slot as shown in Illustration 156.
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   Illustration 158	g06322317
   Incorrect installation, full shutoff position restricted by less than full rack travel. (A) 1.91 mm (0.07520 inch) per tooth

9. If the fuel injection pump installation is NOT correct, the timing pin position will be more that 1.91 mm (0.07520 inch) from the rear face of the timing slot in the rack (refer to Illustration 156.

10. When all fuel injection replacement pumps are installed correctly, complete the assembly and adjustments using the Service Manual.

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NOTICE
If one or more of the fuel injection pumps have been installed wrong, it is possible for the engine to run out of control when started. When any of the fuel injection pumps have been removed and installed with the fuel injection pump housing on the engine, take the precautions (steps) given in the Service Manual to stop the engine if it starts to overspeed (run out of control).

Fuel Pump Bonnet Retaining Bushings

Illustration 159	g06322329
Retaining bushing (1). Do not use heavy lubricant.

When installing fuel pump bonnet retaining bushings on all Caterpillar engines, do not lubricate threads with anti-seize compound or grease. Published tightening torque specifications for bushings on Caterpillar fuel pumps have been established for threads lubricated with diesel fuel or light oil only. Use of anti-seize compound increases tightening forces and may damage the housing.

Chemical Cleaning Process for Bonnet and Barrel Sealing Faces

1. Obtain a container of 1U-9698 Descaleant

2. Provide a clean work area.

   Note: Do not mix plungers and barrels. The original plungers must remain with the same barrels.

3. Use a clean soft cloth to wipe the sealing faces of the barrel and bonnet as clean as possible.

4. Plug the barrel and bonnet bores with a non-damaging material. A 7000 Series nozzle tip cap will fit in the bores.

5. Use the 1U-9698 Descaleant and a cotton swab to scrub the stained sealing surfaces of the bonnet and barrel.

6. Let the descaleant remain on the sealing surfaces for between two minutes (minimum) and five minutes (maximum)

7. Use a cotton swab to repeat the scrubbing action. Then flush the sealing surfaces with clean diesel fuel.

8. Assemble the fuel injection pump groups using the original plungers.

9. Visually inspect the timing spacers and bushings.

10. Install the fuel injection pump groups into a clean fuel injection pump housing. Reuse the timing spacers and bushings. Use new seals. Lubricate the new seals with clean diesel fuel.

11. If the new bushings are NOT required, tighten the bushings to 300 N·m (220 lb ft). If a new bushing is used:

    1. Tighten the bushing to 300 N·m (220 lb ft).

    2. Loosen the bushing 1/4 to 1/2 turn.

    3. Tighten the bushing to 300 N·m (220 lb ft).

       Note: The bushing tightening torque of 300 N·m (220 lb ft) is used for plungers and barrels with face fretting ONLY. Use the standard bushing tightening torque of 260 N·m (190 lb ft) in all other cases.

       Check the rack for free movement after reach bushing is tightened.

Remove Sharp Edges from Fuel Racks (Engines without NSFS)

There have been reports that some of the fuel racks on 3408 and 3412 Engines may have sharp edges on the teeth. These sharp edges can cause wear on the fuel injection pump gears.

Illustration 160	g06322265
Fiber brush a radius at these locations on the racks that have a flat root surface.

• (1) Round root surface

• (2) Flat root surface

• (3) Fiber brush a radius at these locations

The racks used on these engines have two different designs. Only the racks with the flat root surfaces might have sharp edges on the teeth. The other racks have a round root surface. Refer to Illustration 160.

To remove the sharp edges from the fuel racks, use an abrasive fiber grinding wheel (brush) on a bench grinder.

Put a 0.03 - 0.15 mm (0.00118 - 0.00591 inch) radius on each tooth.

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NOTICE
The rack may become hot when the radius is made on each tooth. Do not use water to lower the temperature of the rack.

Make sure all the abrasive material is removed and the rack is clean before it is installed in the pump housing.

Fuel Transfer Pump Leak Test Procedure

This test must be performed with the fuel and the fuel transfer pump at a temperature between 18° - 29° C (64° - 84° F). Check the fuel transfer pump for excessive leakage as follows:

Illustration 161	g06333679
Location to check fuel transfer pump leakage.

1. Fill the pump with fuel, and plug the outlet port.

2. Connect a regulated air supply and a shutoff valve to the inlet port of the pump. Set the regulator to 520 ñ 35 kPa (75 ñ 5 psi). Do not open the shutoff valve at this time.

3. Mount the pump in a vise with the tappet about 3 to 5 degrees below horizontal. Refer to Illustration 161.

4. Wipe off the pump and turn the air supply ON. Make sure that there are no leaks except from between the guide and tappet.

5. Wipe off the face of the guide again. Let a few drops of fuel fall off the guide before starting the count.

6. Count the number of drops of fuel that fall off the guide in one minute. The pump is good if six or less drops fall per minute.

Reworking 3300 / 3406 Fuel Pumps

Illustration 162	g06333682
Location of components in remanufactured OR-3008 and OR-3537 Fuel Transfer Pumps. (1) 7E-2464 Valve (2) 2S-8398 Spring (3) 1W-1698 Housing

The 2S-8398 Spring (2) is used to hold the 7E-2464 Valve Assembly (1) in the remanufactured OR-3008 and OR-3537 Fuel Transfer Pumps, as shown in Illustration 162.

Illustration 163	g06333688
Location of 7E-4656 Retainer. (1) 7E-2464 Valve Assembly (3) 1W-1698 Housing (4) in new fuel transfer pumps.

In new fuel transfer pumps, 7E-2464 Valve Assembly (1) is held in position by 7E-4656 Retainer (4), as shown in Illustration 163. This is possible because new 1W-1698 Housing have been slightly modified in the area where the retainer is installed. The 2S-8398 Spring (2) can be installed in place of retainer (4) when repairing the new fuel transfer pumps.

Increase Fuel Transfer Pump Pressure (for engines without NSFS)

Table 38

Engine Models and Serial Numbers
Model	Serial Number
3408 Industrial	67U
3408 Marine	99U
3408 Generator Set	78Z
3412 Industrial	28S
3412 Marine	7BL, 60M
3412 Generator Set Engines	81Z

Field reports indicate that the fuel transfer pump relief valve may be opening at a lower than specified pressure. The fuel transfer pump relief valve should open and bypass fuel to keep the fuel pressure at the outlet of the fuel transfer pump at 230 ± 35 kPa (33 ± 5 psi) at full rated load. Possible indication of low fuel transfer pump outlet pressure is hard starting and low power.

Illustration 164	g06333743
Location of fuel transfer pump components. (1) 7S-4440 Bolt (2) 4B-4863 Washer (3) 6N-1069 Spring

If low fuel transfer pump outlet pressure is suspected, install a gauge to measure the fuel pressure. To increase the pressure, 4B-4863 Washer (2) can be installed between 7S-4440 Bolt (1) and 6N-1069 Spring (3). Refer to Illustration 164. Measure the fuel pressure at the outlet of the fuel transfer pump at full rated load each time a washer is installed. Install 4B-4863 Washers until a pressure of 230 ± 35 kPa (33 ± 5 psi) is obtained.

A 4N-7465 Gasket is required between 7S-4440 Bolt (1) and the fuel transfer pump housing. Tighten bolt (1) to a torque of 37 ± 4 N·m (27 ± 3 lb ft).

Fuel Injection Pump Housing Test

Illustration 165	g06322395
Test Set Up for Fuel Injection Pump Housing Leak Test. (1) Supply fitting (2) Pressure source (3) Shutoff valve (4) Pressure gauge (5) Cap all bonnets (6) Cap outlet fitting

Illustration 166	g06322398
Locations to Check for Leakage (7) Check this area of housing. (8) Barrel (9) Timing spacer

This test must be performed with the fuel injection pump housing and the fuel at a temperature between 18° - 29° C (64° - 85° F). Test and inspect the fuel injection pump housing, as follows:

1. Disconnect the fuel injection lines and the fuel return line from the pump. Cap all the bonnets and the return line fitting, to prevent leakage when pressure is applied. Fuel injection lines can be modified to cap the bonnets.

2. Disconnect the fuel supply lines, and make sure that the pump housing is full of fuel. Connect a pressure gauge and shutoff valve to the supply fitting, as shown in Illustration 20. Connect an air supply to the shutoff valve. Make sure the caps, connections, shutoff valves, and the gauge do not leak.

3. Apply 480 kPa (70 psi) air pressure to the pump housing. Close the shutoff valve.

4. Observe the pressure loss over a period of five minutes. A pump is good if the pressure loss in five minutes is 35 kPa (5 psi) or less.

5. If the pressure loss exceeds 35 kPa (5 psi) in five minutes, remove each of the injection pumps one at a time. Inspect the seal surfaces of the barrel, timing spacer, and housing, as shown in Illustration 166. Check the surface finish of these parts. Make sure that none of these surfaces have any dirt, debris, nicks, cracks, or scratches on them.

6. Install all the injection pumps in the pump housing. Test the pump housing again for pressure loss.

High Idle RPM

The high idle rpm of an engine is not an adjusted specification. It is the result of three factors:

1. Engine set point rpm (which is adjusted with the high idle screw).

2. The differences of governor springs and weights.

3. Parasitic (accessory) loads on the engine (fan, alternator, compressors, pumps, BrakeSaver, etc.).

The high idle rpm is shown on the engine information plate or listed in the fuel setting charts. The engine information plate must be used for all measurements if it is available

Full Load RPM

Full load rpm is the point at which the engine will develop the rated horsepower. If the engine is equipped with a torque spring, this may or may not be the rpm at which the engine develops maximum horsepower.

Set Point

The engine set point is an adjusted specification and must be maintained. High idle rpm is not an adjusted specification. Set point (formerly balance point) is full load rpm plus an additional 20 rpm. Set point is the rpm at which the fuel rack just starts to make contact with the stop bar or the first torque spring. The rack at this rpm still moves back and forth a small amount. When additional load is put on the engine, the rack will advance and become stable against the torque spring or stop bar. Set point is controlled by the fuel setting in the high idle adjustment screw. Measurements have shown that the former balance point was not a point, but a general area.

The governor springs and weights control the rpm of the engine. Because of the normal production variations in springs and weights of the same part numbers, it is possible to have engines with the same set point but with a different high idle rpm. This is why set point must be adjusted and not high idle rpm.

The parasitic loads on an engine will also cause a change in the measured high idle rpm. These loads will decrease the high idle rpm according to the amount of power used by them. Normally, the parasitic loads on an engine will cause the measured high idle rpm to be 15 to 20 rpm less than the original bare engine high idle rpm with no parasitic loads. The decrease in the high idle rpm caused by the parasitic loads does not change the set point of the engine.

Because set point, governor springs and weights, and parasitic loads all have an effect on the measured high idle rpm on an engine, it is not possible to accurately adjust the governor by only measuring the high idle. The correct way to adjust the governor is to apply a load and use a 6V-2100 Digital Tachometer with either the 6V-4060 Indicator or a continuity light. The 6V-4060 Indicator is the more accurate tool for adjusting the governor and is recommended by Caterpillar. Also, another possible method is to check the engine on a correctly calibrated dynamometer. SEHS7931 Special Instruction, has information for the use of the 6V-4060 Indicator.

Note: An engine set point which is not adjusted correctly, can greatly affect the fuel consumption and the actual performance for that engine.

The performance of the governor can be checked by a measurement of the engine high idle rpm. Make sure that an accurate tachometer is used to check the rpm. If the high idle rpm of a bare engine is within the tolerance shown in the fuel setting charts and its set point is correct, it is an indication that the governor spring and weights are correct and in good condition. No adjustment is necessary. If the engine has parasitic loads on it, 15 to 20 rpm must be added to the measured rpm to allow for their horsepower usage before a comparison is made between it and the high idle rpm specification. If the measured high idle rpm is not within the tolerances of the specification, test the engine with a full rated load applied to see if the set point is correct, before an adjustment is made.

If the set point is correct and the high idle rpm is within the specification, no adjustment is necessary. If the set point is not correct, the high idle screw must be adjusted to get the correct set point rpm. If the measured high idle rpm plus the parasitic rpm allowance of 15 to 20 rpm is higher than the specification, but the set point rpm is correct, then the governor spring and weights can be checked. If the measured high idle rpm plus the parasitic rpm allowance is lower than the specification, but the set point rpm is correct, then the amount of the parasitic loads must be checked before the governor spring and weights are checked.

Remember that the measured high idle rpm of an engine is only a result of the set point rpm. After the set point rpm has been adjusted, the high idle rpm of the engine is controlled by the governor spring and weights and the parasitic loads on the engine.

Illustration 167	g06332003

Illustration 168	g06332004
Effect of a parasitic load on an engine and how the measured engine high idle rpm is lowered from Point B to Point P. A difference of approximately 15 to 20 rpm.

Note: If an adjustment is made to change high idle rpm of an engine with parasitic loads (Point P) to the bare engine specification (Point H), the set point will not be correct. An adjustment too high idle rpm will affect the set point.

Illustration 169	g06332005
Parasitic loads lower the overall tolerance range. The rpm range between Points B1 and B2 is approximately 15 to 20 rpm higher than P1 to P2.

The illustrations which follow show a typical engine power curve. The letters on the curve have these meanings:

Point R is the engine rated full load rpm.

Point S is the engine set point (Point R plus 20 rpm).

Point B is the bare engine high idle rpm specification.

Points B1 and B2 are the acceptable tolerance range of Point B.

Point H is a typical engine high idle rpm measurement.

Point P is the parasitic engine high idle rpm with a parasitic load.

Point P1 and P2 are the range of Point P.

When a governor spring and weight assembly has been put in an engine, that one engine will have a straight line of governor operation. This is shown in Illustration 33 by the line from Point B to Point S. The range in high idle rpm from B1 to B2 would be acceptable for many engines with the same set point. These engines will also each have a straight line of governor operation that starts somewhere at or between Points B1 and B2 and goes to Point S. The difference in the slope between lines BS, B1S and B2S is due to the tolerance range for governor springs and weights of the same part number.

Stop Bolt Adjustment Procedure

Illustration 170	g06332011
Location of electrical shut-off group components.

Perform this procedure after installing stop bolt (2) and cover (5), but before installing solenoid assembly (1).

1. Using the manual shut-off lever, rotate the manual shut-off shaft as far as it will go in the shut-off direction. Hold the shaft in that position.

2. Turn in stop bolt (2) inward until the large end contacts the end of the internal shut-off lever.

3. Turn the stop bolt inward an additional 3/4 ± 1/4 turn. Tighten lock nut (3) and install seal wire (4) and seal.

3408 and 3412 Flex Drive Governor Visual Inspection Procedure (Engines without NSFS)

This section will identify some governor components to check, if there are reports of engine surging during machine operation. These checks are for:

• worn components

• tight fitting components

• tight fitting components

These checks are intended to help with field service and engine performance troubleshooting.

Governor Drive Component Checks (Engines without NSFS)

Illustration 171	g06332015
Location of components (1) Governor Drive Collar (2) Governor Drive Gear Assembly (3) Governor Drive Ring (4) Yoke

Check for worn yoke (4, Illustration 171) on the governor drive assembly. Look for grooves

Illustration 172	g06332018
Components of 6N-4159 Governor Drive Assembly (1) Governor Drive Collar (4) Yoke

(A, Illustration 172) worn on the inside of the yoke legs. If grooves are present, replace the drive assembly. Check for worn dowel

Illustration 173	g06332019
Location of dowels (5) in governor drive assembly (2).

(7, Illustration 173) in governor drive pinion assembly (6). If the dowel is worn, replace it.

Make sure governor drive collar (1, Illustration 171) is a "slip fit" on dowels (5, Illustration 173) in governor drive gear assembly (2). If there is not a "slip fit", replace the governor drive gear assembly.

Illustration 174	g06332021
Location of governor drive pinion assembly (6) and dowel (7).

Illustration 175	g06332023
Location of area of missing tooth (B) on governor drive ring (3).

Make sure the notch in the top of pinion (6) is in alignment with area of missing tooth (B, Illustration 41) in governor drive ring (3). The intent of aligning the notch in the top of pinion (6) with the missing tooth (A, Illustration 172) in the governor drive ring is to provide equal leaf spring travel in either clockwise or counterclockwise direction when the governor drive assembly is installed into pinion (6) and over governor drive gear dowels (5). If travel from the free state is more in one direction than the other, assemble the ring onto the pinion one tooth off the alignment mark to correct the assembly travel. This will provide maximum flex drive travel in both directions.

Rack and Fuel Ratio Control Linkage Adjustment

The new 6V-6070 Governor Adjusting Tool Group has the tools that are needed to check and adjust the rack and the fuel ratio control linkage on all engines with New Scroll Fuel Systems (NSFS). This new tool group is a replacement for the former 6V-4095 and 6V-4096 Groups which are canceled. All the tools in the former groups except for the 6V-2128 Compressor are still serviced. The 6V-2128 Compressor is canceled.

Two of the new tools in the 6V-6070 Governor Adjusting Tool Group are the 6V-7941 Overfueling Spring Compressor and 6V-7942 Hook. The new 6V-7941 Overfueling Spring Compressor has enough movement so it can be used on 3204, 3304, 3306, and 3406 Engines with NSFS.

The 6V-7942 Hook is used to pull the rack against the rack centering pin on engines with negative rack settings. This is because on some of these engines the overfueling spring may not move the rack against the centering pin.

A new procedure is now used to check and adjust the rack on these engines. Special Instruction, SEHS8024, has complete information for the use of the new tools.

Table 39

Components of 6V-6070 Tool Group
Quantity	Part Number	Description
2	0S-1614	Bolt
1	0S-1615 (1)	Bolt
1	2A-0762 (1)	Bolt
1	2P-8264	Socket
1	2P-8265	Socket
1	5B-5689	Gasket
2	5P-4814 (2)	Collet
1	6V-2014	Bracket Assembly
2	6V-2015	Arm (Part of 6V-2014)
1	6V-2017	Tool
1	6V-2030 (1)	Extension
1	6V-2106	Tool Group
1	6V-3075	Indicator
1	6V-4186	Pin
1	6V-6104 (3)	Block
1	6V-6105 (1)	Block
1	6V-6106 (1)	Indicator
1	6V-6108 (1)	Arm (Part of 6V-6109)
1	6V-6109 (1)	Bracket Assembly (Rack Indication)
1	6V-4859 (1)	Case (Plastic)
1	6V-6151	Adapter (Overfueling Spring Compressor)
1	6V-7941	Compressor Assembly
1	6V-7942	Hook
3	8H-3128	Bolt
2	8H-9178 (1)	Bolt
1	9S-0229	Point
1	9S-8903 (1)	Point
1	021-7956	Bolt
1	SEHS8024	"Use of 6V6070 Governor Adjusting Tool Group"
1	SEES5640	Label
1	SEES5461	Layout Chart

(1)	These are new parts which are only used on 3406 Engines.
(2)	Formerly, only one 5P-4814 Collet was used. The new collet is used on 3406 Engines.
(3)	These are new parts which are not part of either of the former groups.

Check Assembled Dimension for Rack Lever Travel

Table 40

Recommended Parts
Part Number	Description	Quantity
2W-9305	Plate (1)	1
8N-3087	Stop (1)	1

(1)	This part may be required when replacing the 8N-2501 Governor Housing Assembly.

When replacing the 8N-2501 Governor Housing Assembly in 3300 Engines with Scroll Fuel Systems, it is possible to have an interference between components within the governor or the rack may not move all the way to the "Fuel Off" position. These conditions may exist because of casting shifts during the manufacturing process of the governor housing.

To ensure that the governor will function properly, it is necessary to check the assembled dimension for rack lever travel and possibly replace the original 8N-3087 Stop and 2W-9305 Plate. Follow the procedure in this instruction to perform this check.

Illustration 176	g06332188

1. Assemble the components of the governor group using a new 8N-2501 Governor Housing Assembly and the original 8N-3087 Stop and 2W-9305 Plate. Refer to the Service Manual for the assembly procedure

2. Measure the distance between the face of the governor housing assembly and rack lever dimension (A). This dimension should be 18.6 ± 1.0 mm (0.73228 ± 0.03937 inch).

3. If dimension (A) is within the specified limit of 17.6 to 19.6 mm (0.69291 to 0.77165 inch), install the governor assembly.

   1. If dimension (A) measured in Step 2, is greater than 19.6 mm (0.77165 inch), proceed to Step 4.

   2. If dimension (A) measured in Step 2, is less than 17.6 mm (0.69291 inch), proceed to Step 6.

Illustration 177	g06332199
(1) 8N-3087 Stop (2) 2W-9305 Plate (3) Grind Location

1. Remove 2W-9305 Plate (2) and grind some material from the plate at area (3) shown shaded in Illustration 177. Reinstall plate (2) and check for correct dimension (A).

2. Install the governor assembly when the correct dimension (A) has been achieved.

3. Remove the original 8N-3087 Stop (1) and 2W-9305 Plate (2), and replace with new parts.

4. Check dimension (A) using Step 2. Install the governor assembly when the correct dimension (A) has been achieved.