MITSUBISHI ENGINES REF. 4D31 ENGINE FOR Caterpillar

5. Service Procedures

Usage:

Wherever possible, test the fuel system parts before disassembly to precisely know their conditions. Select a clean site for disassembly and reassembly work, as even small dust particles on the fuel system parts can adversely affect engine performance.

When disassembling the injection pump, keep work bench clean and disassembled parts neatly arranged for each cylinder. Use special care to ensure correct combination of plunger and plunger barrel and of delivery valve and delivery valve seat.

Scrupulous care must be exercised when disassembling and reassembling critical parts.

Use the specified special tools for disassembly and reassembly; never apply excessive force or handle parts carelessly.

Before disassembly, test the system to know exactly the trouble spots.

5-1 A Type Injection Pump <4D31, 4D30, DR (Nippondenso Products) >

5-1-1 Removal

1 Fuel hose

2 Injection pipe

3 Leak off pipe <4D31>

4 Oil pipe

5 Injection pump stay

<4D31, 6DR5>

6 Injection pump

Hold the injection pump by hand, and remove five timer case attaching bolts.

Then, remove the injection pump, pulling it rearward.

Use of Socket Wrench (special tool) will make the removal of timer case attaching bolts easier.

5-1-2 Disassembly

For disassembly of parts with an encircled number, see following items.

Inspection items marked with * must be checked before disassembly

NOTE:

1. Keep disassembled parts neatly arranged for each cylinder.

2. Keep plunger, plunger barrel, and delivery valve in gas oil.

(1) With the auto timer and timer case removed, install the injection pump on Pump Mounting Base and Pump Setting Angle (special tools).

(2) Using Box Wrench (special tool), remove the feed pump.

(3) Remove the governor and cover plate.

RSV governor ... (See 5-3-1)

RU governor ... (See 5-5-1)

MZ governor ... (See 5-6-1)

(4) Measure the control rack sliding resistance.

Turn camshaft to ensure that the resistance is up to specification in any position.

If the nominal value is exceeded, possible causes are as follows:

* Damage on control rack and defective tooth* Defective pinion tooth, pinion in contact with housing* Excessively tightened delivery valve holder

(5) Using Coupling and Round Nut and Holding Spanner (special tools), turn the camshaft to bring the tappet to TDC.

Insert Tappet Insert (special tool) in the tappet service holes successively to separate the camshaft from the tappet.

(6) Mount Camshaft Clearance Gauge (special tool) on the camshaft to measure the end play.

(7) Remove the camshaft, tapping it with a soft hammer from the governor end.

On 6DR5, before removing the camshaft, remove center bearing.

NOTE:

1. Make sure that the cams on camshaft are not in contact with the tappet.

2. Install the flyweight round nut at the end of camshaft to protect threads.

(8) Accessing from the bottom of the pump, insert Roller Clamp (special tool) to push up the tappet. Remove Tappet Insert (special tool).

(9) Move the tappet with Roller Clamp (special tool), and insert Tappet Clamp (special tool) into the camshaft hole to take out the tappet.

(10) Insert Plunger Clamp (special tool) from the bottom of the pump and fix its end to the lower spring seat. Then, withdraw the special tool with plunger.

NOTE: When removing, ensure that the notch in the lower spring seat (for inserting the plunger) faces up to prevent the plunger from dropping.

(11) Measure the backlash between control rack and pinion. If the limit is exceeded, replace parts.

(12) Remove the lock plate and remove the delivery valve holder with Box Spanner (special tool).

Then, remove the stopper, delivery valve, and spring.

(13) Using Delivery Valve Extractor (special tool), remove the delivery valve.

(14) Remove the plunger barrel.

NOTE: Keep a plunger and plunger barrel pair in gas oil.

5-1-3 Inspection and Correction

(1) Plunger and Plunger Barrel

After cleaning in gas oil, check if the plunger falls smoothly in the plunger barrel under its own weight.

Use the following procedure for the inspection:

* Tilt the plunger barrel approximately 60°.* Pull the plunger about 10 to 15 mm and let it go.* Turn the plunger to check on several more points.

Replace the plunger if it does not fall.

(2) Delivery Valve

Clean the valve and valve seat of the delivery valve in gas oil and check for wear.

Seal off the bottom of the valve seat with a finger, and press the piston with a finger. If the piston bounces back when released, the valve is in good condition. If not, replace the valve as it must be badly worn.

NOTE: With the engine provided with the Ungleigh cut <4D31>, the above procedure is not effective since the piston does not spring back.

(3) Tappet

Apply a dial indicator to the tappet roller and check for over-all clearance by moving the roller up and down with a rod. If the clearance exceeds the limit, replace the tappet assembly.

Measure the clearance between the tappet and pump housing and, if the limit is exceeded, rplace parts.

(4) Lower Spring Seat

Check the lower spring seat surface in contact with the plunger for wear. If the limit is exceeded, replace the lower spring seat.

(5) Plunger Spring and Delivery Spring Valve

Measure the squareness of the springs and, if the limit is exceeded, replace.

(6) Replacement of Taper Roller Bearing

Inner Race

Using gear puller, remove the rolle and inner race from the camshaft.

For installation, put ring and shim and the press-fit the bearing.

NOTE: Use shims of nearly the same thickness on both ends of the camshaft.

Outer Race

To remove the outer race on the cover end, use Camshaft Outer Race Remover (special tool).

Install by using a press.

(7) Camshaft Bend (Runout)

Support the camshaft with a V-block at its ends (or the center holes at both ends), and check for bend at the center with a dial indicator.

If the limit is exceeded, correct with a press or replace.

5-1-4 Reassembly

(1) Mount the control rack and rack guide screw.

NOTE: Make sure that the rack moves smoothly. Check also to ensure that the rack does not turn when so attempted.

(2) At installation, ensure that the knock pin fitted into the pump housing is aligned with the locating notch in the plunger barrel.

Make sure that the knock pin projects by about 0.7 mm from the housing. If the projection is smaller than that, drive pin out from the housing side.

NOTE: Note that the pump housing area must be cleaned, into which the plunger barrel is inserted.

(3) With a new gasket installed in the delivery valve, drive the valve into position until it is held tightly against the plunger barrel top surface, using Delivery Valve Gasket Installer (special tool).

(4) Fit the delivery valve spring and stopper into position, and temporarily tighten the delivery valve holder.

(5) With the control rack set at the center, install the control pinion and control sleeve.

NOTE:

1. Install with the control pinion joint and the control sleeve notch facing to your side.

2. Every time a pinion is in mesh, move the control rack to make sure that the control pinion joint evens out at right and left. (This is done to ensure an rack full stroke of 21 mm).

(6) Fit Plunger Clamp (special tool) into the lower spring seat, and install the plunger into the lower spring seat.

Insert the plunger into the plunger barrel with care not allow the plunger end to hit the pump housing and plunger spring.

NOTE:

1. After the plunger has been installed, turn the lower spring seat to face its notch downward. This prevents the spring seat from coming off position.

2. Make sure that the plunger flange side with a part number marking faces upward.

(7) Clamp the tappet with Tappet Clamp (special tool) and, with the tappet guide aligned with the housing groove, insert it into the pump housing.

(8) Using Roller Clamp (special tool), push the tappet to TDC. Then, insert Tappet Insert (special tool) and remove Roller Clamp (special tool).

Make sure that the part number marking on the plunger flange is positioned on the cover plate side.

For each cylinder, check the control rack for sliding condition each time Tappet Insert (special tool) is installed.

(9) Tighten the delivery valve holder to the specified torque.

Check also the control rack for sliding condition each time the holder is tightened.

(10) Install the camshaft with the marking line at the end of its threads facing toward the drive end.

(11) Temporarily mount the bearing cover to measure the camshaft end play with Camshaft Clearance Gauge (special tool). If the limit is exceeded, adjust with shims or replace bearing.

NOTE: Use shims of almost equal thickness for the governor and timer end.

Shim Thickness

After installing the bearing cover in position, measure again the end play to ensure that it is up to specification.

(12) With Tappet Insert (special tool) removed, measure the sliding resistance of the control rack. [See 5-1-2, (4).]

(13) Install governor.

(14) Install the following parts after adjusting the injection pump:

* Control rack cover* Cover plate* Timer case* Feed pump* Auto timer [See 5-8-1, (4).]

5-1-5 Adjustment after Reassembly

For fuel injection rate adjusting standard, see Service Information separately published.

NOTE: Feed oil into the injection pump cam chamber.

(1) "0" Position Setting of Control Rack

With the auto timer and timer case removed, install Coupling and Round Nut (special tool) and set a tester on the injection pump.

Remove the control rack cover and install Rack Position Measuring Device (special tool), instead. Loosen the idling set bolt and full load set bolt.

Push the control rack all the way to the governor and regard this position as "0" of the Rack Position Measuring Device (special tool).

Remove the delivery valve spring and stopper from the delivery valve holder.

Feed the engine oil into the injection pump and bleed fuel of air.

(2) Checking the Control Rack Stroke (with RSV or RU Type Governor)

Check the control rack for return motion when it is pushed all the way to the governor and released.

The rack is in good condition if it returns smoothly and the return stroke is within specification.

(3) Measurement of the Control Rack Sliding Resistance (with MZ Type Governor)

Drive injection pump at 1 000 rpm with diaphragm removed and measure the sliding resistance of the control rack.

Check that the resistance is within the nominal range and the control rack is pulled smoothly.

(4) Measurement of Prestroke

(a) Fix the control rack position at 21 mm and set Prestroke Measuring Device (special tool) on the tappet guide of No. 1 cylinder.

(b) With No. 1 cylinder plunger placed at BDC, feed fuel under pressure to the injection pump with the high-pressure pump of the pump tester. Then, let the fuel flow out from the overflow pipe of the test nozzle.

(c) Slowly turn the tester coupling until the fuel stops flowing out of the overflow pipe (static injection starts).

NOTE: Measurement must be made with the camshaft turned in the normal rotating direction (clockwise as viewed from the drive end).

The plunger stroke from BDC until fuel stops flowing is called the prestroke. Read the prestroke on the dial indicator.

NOTE: When measuring the prestroke, ensure that the adjusting lever is in full load position.

If the prestroke is out of specification, adjust as follows.

(5) Adjustment of Prestroke

With the tappet at TDC, insert Spring Holder (special tool) between the lower spring seat and tappet.

Turn camshaft, and you have a clearance between the lower spring seat and tappet. Increase or decrease shim thickness to fill the clearance, to adjust the prestroke.

A greater shim thickness makes prestroke smaller.

A smaller shim thickness makes prestroke greater.

(6) Measurement of Injection Start Interval

With the static injection start of No. 1 cylinder used as a basis, read the injection start iterval of each cylinder according to the injection sequence using an angle scale of the tester.

If the interval is out of specification, adjust as in prestroke adjustment.

Injection Sequence

(7) Measurement of Tappet Clearance

Install Prestroke Measuring Device (special tool) and turn the camshaft to bring the tappet to TDC.

Using Tappet Clearance Bar (special tool), push up the tappet and measure the lift until the plunger flange top surface comes in contact with the plunger barrel.

If the tappet clearance is out of specification, adjust within the allowable limit of the fuel injection start intervals. If adjustment is not possible within the limit, read just with the No. 1 cylinder prestroke at the maximum nominal value.

(8) Adjustment of Fuel Injection Rate

Measure the fuel injection rate and uneven ratio with the specified rack position and speed.

If the injection rate is out of specification, adjust as follows.

* Slightly back off the pinion clamp screw.* With the control rack fixed at a position, turn the control sleeve with the adjusting rod.* Tighten the pinion clamp screw.

NOTE:

1. Use special care to make the correct adjustment. Improper or failure of adjustment greatly affects engine performance.

2. Observe measurement conditions strictly, as the fuel injection rate varies with different nozzle and pipe used.

3. Uneven ratio = Max. injection rate in each cylinder - Min. injection rate in eacy cylinder.

(9) Adaptation to Engine

After the governor has been adjusted, measure the fuel injection rate adaptable to the engine.

(10) Inspection of Fuel and Oil Leaks

Check the delivery valve mounting position and other parts for fuel leak.

Check oil seals and other parts for oil leak.

(11) Inspection of Unusual Conditions

Check for unusual noise, heat, and other abnormal conditions.

5-1-6 Installation

1 Injection pump

2 Injection pump stay

<4D31, 6DR5>

3 Oil pipe

4 Leak off pip <4D31>

5 Injection pipe

6 Fuel hose

(1) Set the piston of the engine No. 1 cylinder at the top dead center on compression stroke. For this purpose, use Cranking Handle (special tool) to crank the engine until the engraved line "0" position on the side bearing "1.4" mark of the crankshaft pulley (in the case of 4DR5, engraved line "0" of the crankshaft pulley and in the case of 6DR5, engraved line "1.6" on the flywheel) is lined up with the pointer.

In the case of 4D3, another pointer is on top of the crankshaft pulley and if this pointer is used, align the engraved line "0" position on the side bearing "2.3" mark of the crankshaft pulley with the pointer.

At this time, if the intake and exhaust valves of the No. 1 cylinder are not pushed up by the push rod, the No. 1 cylinder is at the top dead center on compression stroke. If the intake and exhaust valves are pushed up by the push rod, turn the crankshaft through 360 degrees.

(2) Line up the marking on the timer case with the notch in the injection pump gear.

(3) Insert the guide bar on the timer case into the guide hole in front plate. Using this as a guide, push until the injection pump gear is about to be in mesh with the idler gear.

(4) Make sure that the alignment mark of the injection pump gear is aligned with that of the timer case. Then, push in the injection pump. At the time, the alignment mark on the gear moves to the end of that on the timer case.

5-1-7 Bleeding the Fuel System

Here is the procedure for bleeding the fuel system.

(1) Turn the injection pump priming pump counterclockwise until it comes loose.

(2) Loosen the air plug of the fuel filter.

(3) Move the priming pump up and down by hand to feed fuel until air bubble does not come out from the air plug.

(4) When no air bubble comes out in fuel, keep the priming pump down and turn it clockwise until it fits into position. Then, tighten the air plug.

NOTE:

1. The air plug must be tightened after the priming pump is secured into position.

2. Sop up fuel spilt around.

(5) Actuate the starter to discharge air from the injection pump.

NOTE: Do not operate the starter for more than 15 seconds.

On 4D30 and DR, the injection pump is provided with an air bleeder which can be loosened for bleeding as with the fuel filter.

5-1-8 Inspection and Adjustment after Installation (Fuel Injection Timing)

(1) Remove the injection pipe, delivery valve, delivery valve spring, and stopper from No. 1 cylinder of the injection pump. Keep the delivery valve holder attached.

NOTE: Keep disassembled parts in gas oil to prevent contamination by dust and dirt.

(2) Install a spare injection pipe to No. 1 cylinder. Face the other end of the pipe downward for easier observation of fuel flow out condition.

(3) Crank the engine to bring the piston in No. 1 cylinder 30° before top dead center

(4) While operating the priming pump to let fuel run out from the injection pipe, slowly crank the engine in the direction of normal rotation.

NOTE: Make sure that the stop lever on the governor is not pulled toward the STOP position.

(5) Crank the engine even more slowly as the fuel is about to stop flowing out from the injection pipe. Stop cranking as soon as no more fuel comes out from the pipe.

(6) Check that the inscribed line on the flywheel and the pointer indicate the position about 2 degrees before the fuel injection timing.

NOTE:

1. The injection timing is advanced by about 2 degrees from specified timing as the delivery spring's valve opening pressure does not work.

2. The injection timing is indicated at the caution plate on the rocker cover.

If the timing is out of specification, adjust as follows.

(7) Loosen the injection pump attaching nut with Universal Extension (special tool).

(8) To advance the fuel injection timing, move the injection pump toward the crankcase side.

To retard the timing, move the injection pump away from the crankcase.

(9) Move the injection pump to the desired direction. A shift of one graduation of the adjustment marker varies the injection timing by 3 degrees.

(10) With the injection pump attaching nut tightened, measure the injection start timing again.

(11) After the adjustment has been made, install the delivery valve, delivery valve spring, and stopper and tighten the delivery valve holder to specification. Then, install the injection pipe.

(12) For inspection at dusty locations, proceed as follows.

(a) Remove only the injection pipe and keep a small amount of fuel remaining at the top of delivery valve holder.

(b) Crank the engine to bring the piston in No. 1 cylinder to a position about BTDC 30° on the compression stroke. Further crank the engine slowly, and the fuel on top of the delivery valve will begin to move.

(c) This is the fuel injection start timing.

NOTE: If the fuel ijection timing is radically different from the specification and the deviation is beyond the adjustable range of the injection pump, the engine timing gear and injection pump gear are not probably in proper mesh. In this case, remove the injection pump and reinstall it according to 5-1-6.

5-2 A Type Injection Pump <4D31-T (Diesel Kiki Products)>

5-2-1 Removal

For removal procedure, see 5-1-1.

5-2-2 Disassembly

For disassembly of parts with an encircled number, see following items.

Inspection items marked with * must be checked before disassembly.

NOTE:

1. Keep disassembled parts neatly arranged for each cylinder.

2. Keep plunger, plunger barrel, and delivery valve in gas oil.

(1) With the auto timer and timer case removed, install the injection pump to the Universal Vise (special tool) and remove following parts.

* Feed pump* Governor (See 5-3-1 or 5-4-1.)* Cover plate

(2) Measure the sliding resistance of the control rack.

Turn the camshaft to check that the value is as specified when measured at any position.

If the measurement exceeds specification, possible causes are:

* Damage on control rack, defective teeth* Defective pinion teeth, pinion in contact with housing* Excessively tightened delivery valve holder

(3) Turn the camshaft to place the tappet at TDC.

Insert Holder (special tool) into the tappet, one by one, to keep them off the camshaft.

(4) Install Measuring Device (special tool) to the camshaft and measure the end play.

(5) Remove the screw plug from the bottom of injection pump with Handle (special tool).

(6) Install Seal Guide (special tool) to the camshaft end (threads and keyway).

Remove the bearing cover by inserting a screwdriver into notches at top and bottom of bearing cover.

If the bearing cover is hard to remove, tap the camshaft with a soft hammer from the governor end.

Remove camshaft at the same time.

NOTE: Whenever the bearing cover is disassembled, its oil seals must be replaced with new ones.

(7) Using Tappet Insert (special tool), push the tappets from under the injection pump. Remove Holders (special tool).

(8) With the tappet held in position with Tappet Insert (special tool), insert Inserter (special tool) into camshaft hole to remove tappet.

(9) Insert Extractor (special tool) from the bottom of the pump and fix its end to the lower spring seat. Then, withdraw the special tool, which removes the lower spring seat with plunger.

NOTE: When removing, ensure that the notch in the lower spring seat (for inserting the plunger) faces up to prevent the plunger from dropping.

(10) Measure the backlash between the control rack and pinion. If the limit is exceeded, replace.

(11) Remove the lock plate and use Socket (special tool) to remove the delivery valve holder. Then remove the stopper and delivery valve spring.

(12) Using Delivery Valve Extractor (special tool), remove the delivery valve.

(13) Remove the plunger barrel.

NOTE: Keep the plunger and plunger barrel in original combination and leave them immersed in gas oil.

5-2-3 Inspection and Correction

(1) Plunger and Plunger Barrel

After cleaning in gas oil, check to see if the plunger falls smoothly in the plunger barrel by its own weight.

For inspection, use the following procedure:

* Tilt the plunger barrel about 60°.* Pull the plunger out by about 20 mm, and let it go.* Make the check several times by turning the plunger.

If the plunger does not fall by gravity, replace.

(2) Delivery Valve (with Ungleich Cut)

After cleaning the valve and valve seat of the delivery valve in gas oil, check for wear.

(3) Tappet

Set a dial indicator to the tappet roller and move roller up and down with a rod to check for overall clearance.

If the overall clearance exceeds the limit, replace as a tappet assembly.

Measure the clearance between the tappet and pump housing and, if the limit is exceeded, replace parts.

(4) Lower Spring Seat

Check the lower spring seat surface in contact with the plunger for wear and, if the limit is exceeded, replace.

(5) Replacement of Taper Roller Bearing

Inner Race

To remove the inner race, use Extractor (special tool) and remove the roller and inner race from the camshart.

At installation, press-fit the ring, shim, and bearing, in that order.

NOTE: Install shims of almost the same thickness on both ends of camshaft.

Outer Race

To remove the outer race, use Extractor (special tool).

For installation, use a press.

5-2-4 Reassembly

(1) Mount the control rack and rack guide screw.

NOTE: Check to see if the rack moves smoothly. Check also if the rack does not turn.

(2) At installation of the plunger barrel into the housing, align the notch in the plunger barrel with the housing knock pin.

NOTE: Do not tap the plunger barrel, but push into position with a finger.

(3) Place the injection pump horizontally, and set the control rack so that its marking lines are positioned at the same distance away from the housing end faces.

Mate the control pinion with control sleeve and put the pinion in mesh with the control rack teeth.

NOTE:

1. Make sure that the joint of control pinion and notch in control sleeve face toward you.

2. Move the control rack each time the pinion is in mesh to ensure that the control pinion joint evens out at right and left. (This is done to ensure an entire rack stroke of 21 mm.)

(4) Fit Extractor (special tool) into the lower spring seat, and install the plunger into the lower spring seat.

Insert the plunger into the plunger barrel with care not to allow the plunger end to hit the pump housing and plunger spring.

NOTE:

1. After the plunger has been installed, turn the lower spring seat to face its notch downward. This prevents the lower spring seat from coming off position.

2. Make sure that plunger flange side with a part number marking faces upward.

(5) Clamp the tappet with Inserter (special tool) and with the tappet guide aligned with the housing groove, install it into the pump housing.

(6) Using Tappet Insert (special tool), push the tappet to TDC, insert Holder (special tool) and remove Tappet Insert (special tool).

At this time, make sure that the part number marking on the plunger flange is positioned on the cover plate side.

For each cylinder, check the control rack for sliding condition each time Holder (special tool) is installed.

(7) Using Socket (special tool), install the delivery valve holder.

(8) Install the camshaft with the marking line at the end of its thread facing toward the drive end.

(9) Temporarily mount the bearing cover to measure the camshaft end play with Measuring Device (special tool). If the limit is exceeded, adjust with shims or replace bearing.

NOTE: Use shims of almost equal thickness for the governor and timer end.

After installing the bearing cover in position, measure again end play to ensure that it is up to specification.

(10) With Tappet Insert (special tool) removed, measure the sliding resistance of the control rack. [See 5-2-2, (2).]

(11) Apply sealant to screw plug and install it with Handle (special tool).

(12) Install the governor.

(13) Install the following parts after adjusting the injection pump:

* Control rack cover* Cover plate* Timer case* Feed pump* Auto timer [See 5-8-2, (4).]

5-2-5 Adjustment after Reassembly

For fuel injection rate adjusting standard, see Service Information separately published.

NOTE: Feed oil to the injection pump cam chamber.

(1) Control Rack "0" Position Setting

Install Measuring Device (special tool) on the injection pump.

Temporarily set the adjusting lever to maintain the injection pump speed at 500 to 600 rpm. Further increase the speed to pull the control rack; at the same time, push the control rack fully.

With this position of control rack regarded as "0", set "0" on the Measuring Device scale to the position.

NOTE: If zero position is set by the adjusting lever operation without running the injection pump, the governor linkage could be damaged. Do not use the adjusting lever to set the zero position.

(2) Control Rack Stroke Check

Move the control rack to check its stroke is more than the specified value.

Ensure also that the start spring and idling spring move the control rack smoothly in the direction to increase the amount of fuel injected.

(3) Prestroke Check

(a) With the control rack withdrawn and fixed in the full injection position, install Measuring Device (special tool).

(b) With No. 1 cylinder plunger at BDC, send fuel to injection pump under high pressure with the high pressure pump of the pump tester and install Nozzle Holder Wrench (special tool) to test nozzle to let the fuel flow out from overflow pipe.

NOTE: The fuel pressure must be over the delivery valve opening pressure.

(c) Slowly turn the tester coupling until the fuel stops flowing out of the test nozzle overflow pipe (static injection starts).

NOTE: Measurement must be made with the camshaft turned in the normal rotating direction (clockwise as viewed from the drive end).

(d) Read the prestroke of plunger on the indicator, from BDC until fuel stops flowing.

If the prestroke is out of the nominal value, adjust as follows [See (4)].

(4) Adjustment of Prestroke

With the tappet at TDC, insert Holder (special tool) between the lower spring seat and tappet.

Turn camshaft, and you have a clearance between the lower spring seat and tappet. Increase or decrease shim thickness to fill the clearance, to adjust the prestroke.

A greater shim thickness makes prestroke smaller.

A smaller shim thickness makes prestroke greater.

(5) Measurement of Injection Start Interval

With the static injection start of No. 1 cylinder used as a basis, read the injection start interval of each cylinder according to the injection sequence using an angle scale of the tester.

If the interval is out of specification, adjust as in prestroke adjustment.

Injection Sequence

(6) Tappet Clearance Measurement

Install Measuring Device (special tool) and turn the camshaft to bring the tappet to TDC.

Push up the tappet and measure the lift for the plunger flange top to come into contact with the plunger barrel.

If the tappet clearance is out of specification, adjust within the allowable range of injection start interval. If the range does not permit correction, read just with No1. 1 cylinder prestroke at the maximum nominal value.

(7) Fuel Injection Rate Adjustment

Measure the fuel injection rate and uneven ratio at the specified rack position and speed.

If the injection rate is out of specification, adjust as follows.

(a) Loosen pinion clamp screw.

(b) With the control rack held in position, turn the control sleeve with the adjusting rod.

(c) Tighten pinion clamp screw.

NOTE:

1. Use special care to make the adjustment. Improper or failure of adjustment greatly influences engine performance.

2. The fuel injection rate vaies with nozzle and pipe used. Observe measuring requirements strictly.

3. Uneven ratio

(8) Adaptation to Engine

After the governor has been adjusted, measure the fuel injection rate adaptable to the engine.

(9) Inspection of Fuel and Oil Leaks

Fuel leaks from delivery valve attaching portion and other parts

Oil leaks from oil seals and other parts

(10) Inspection of Parts

Check parts for unusual noise and bearings for excessive heat.

5-2-6 Installation

For Installation, see 5-1-6.

5-2-7 Bleeding the Fuel System

For Bleeding, see 5-1-7.

5-2-8 Inspection and Adjustment after Installation

For Inspection and adjustment, see 5-1-8.

5-3 RSV Type Governor

5-3-1 Disassembly, Inspection and Reassembly

For disassembly and reassembly of parts with an encirled number, see following items.

NOTE:

1. Do not disassemble the shackle and governor sleeve from the guide lever, unless replacement is necessary.

2. Do not remove the governor housing unless removal is necessitated for correction of oil leaks, parts replacement, etc.

Before removing the housing, use Tappet Insert (special tool) to separate the camshaft from the tappet.

For reassembly, reverse the order of disassembly.

Disassembly Procedure

(1) Remove the governor cover assembly from the governor housing.

Open the governor cover slightly to the front and slide downward the shackle latch connected to the control rack to disconnect it from the control rack.

(2) Remove the start spring using long-nose pliers.

(3) Remove the round nut using Socket Wrench or Round Nut Wrench (special tools).

(4) Screw in Extractor (special tool) to the flyweight and extract it.

(5) Removal of Swivel Lever

Remove the snap ring from the lever bushing and tap lightly the swivel lever shaft from the adjusting lever mounting side to remove the bushing from both ends. Then, remove the swivel lever.

NOTE: Do not remove the swivel lever from the governor cover unless such removal is necessary for parts replacement or for correcting unsmooth motion.

(6) Replacement of the Governor Sleeve or Guide Lever

(a) Using a press, remove the bearing in the governor sleeve and remove the guide lever assembly shifter from the bearing.

(b) Press-fit the bearing to the governor sleeve.

Press-fit the guide lever assembly shifter to the bearing.

(c) Make sure that the sleeve turns smoothly.

NOTE:

1. Do not replace the shim as its thickness has been established.

2. During removal and installation take care not to damage the chromium plated surface of the shifter.

Reassembly Procedure

(1) If shims have to be replaced, assemble the associated parts correctly and select the thickness of shims that gives correct housing end to shifter dimension.

Shim Thickness

(5 types: Nippondenso products) 0.1, 0.2, 0.3, 0.4, 1.0 mm

(6 types: Diesel Kiki products) 0.2, 0.3, 0.4, 0.5, 1.0, 1.5 mm

NOTE: Measure the assembled dimension without lifting the flyweight.

(2) When mounting the governor spring to the swivel lever, position the spring so that its end faces the shackle.

5-3-2 Adjustment after Reassembly

For governor performance curve, see Service Information separately published.

NOTE:

1. Supply engine oil to the injection pump cam chamber.

2. Loosen the adjusting lever stopper bolt.

3. Remove the idling subspring.

4. Do not allow the Ungleich spring and torque spring to work.

Adjust the relationship between the pump speed and the rack position to the specified governor performance curve as follows.

(1) "0" Position Setting of Control Rack

See 5-1-5 (1) ... Nippondenso products

See 5-2-5 (1) ... Diesel Kiki products

(2) Mount the angle scale plate for the adjusting lever fixing device.

(3) Adjustment of Intermediate Speed Control

This adjustment sets the control rack position point C (maximum injection) when the injection pump is at full load.

With the injection pump at Nc rpm, set the adjusting lever to its tilted position where the governor spring in the governor is tensioned fairly strongly and hold the lever at that position temporarily.

Then, adjust the full load stopper to bring the control rack to the Rc position.

Turning the full load stopper clockwise as viewed from the rear of the governor moves the rack in the direction that fuel is increased and turning in counterclockwise moves the rack in the direction that fuel is decreased.

(4) Adjustment of Ungleich

Set the adjusting lever at the maximum speed stopper position.

Adjust the adapter screw so that the rack position changes from Ra to Rc when the speed is changed from Na to Nb. The change in the rack position from Ra to Rc is called the Ungleich stroke.

Tightening the adapter screw increases the Ungleich stroke and loosening the screw decreases the Ungleich stroke.

Change the thickness of shim plate (Nippondenso products) the Ungleich spring assembly (Diesel Kiki products) so that the rack is positioned at Ra when the speed is Na.

Shim Thickness (4 types)

0.10, 0.20, 0.25, 0.50 mm (Nippondenso products)

(5) Adjustment of Low Speed Control

(a) Adjustment of stopper bolt

While rotating the pump at Ni, tilt the adjusting lever and adjust the stopper bolt to bring the control rack to the Ri position.

(b) Adjustment of idling subspring

Adjust the idling subspring so that the rack is positioned at Rh when the pump is running at a speed of Nh.

Then, decrease the pump speed and check that the rack is positioned at Rg at the pump speed of Ng.

(6) Adjustment of High Speed Control

(a) Adjustment of maximum speed stopper

Tilt the adjusting lever and set the maximum control speed of the governor.

Tilt the adjusting lever and adjust the maximum speed stopper so that the control rack is moved from the Rc position when the pump speed increased slowly from Nc reaches Nd.

(b) Adjustment of speed variation rate

Increase the pump speed from Nd and check to see that when the speed reaches Ne, the rack position is pulled back to Re.

If it is out of specification, adjust the amount the adjusting screw of the swivel lever is turned down.

Tightening the screw will improve the speed variation rate.

Loosening it will worsen the speed variation rate.

NOTE:

1. If the variation rate is poor, the engine will exceed the specified maximum speed at no load and will enter a hazardous condition.

2. The maximum extent to which the adjusting screw can be loosened is 20 notches (5 rotations) from the fully tightened position. Loosening it any further can be dangerous.

3. If the adjusting screw is adjusted, the tension of the governor spring will change and the high speed control start point will change. Make sure that the maximum speed stopper under Item (a) is readjusted.

(7) Stop Lever Operation Check

With the injection pump at full load, move the stop lever fully to the stop side and check that this moves the rack to the 0 mm position.

(8) Adjustment for Adaptation to Engine

Upon completion of the governor adjustment, measure the total injection amount with the lever set at the same angle as in the high speed control in accordance with the adjustment standard and adjust as necessary.

(9) Sealing

After all adjustments have been made, seal the governor as follows.

NOTE: Sealing of the sections marked with * must be done after adjustment of no-load minimum and maximum speeds.

5-3-3 Inspection and Adjustment of No-load Minimum and Maximum Speeds

Start engine and warm up sufficiently. After the temperature of coolant exceeds 60°C, perform the following inspection and checks.

(1) Minimum Speed

(a) Make sure that the adjusting lever is in contact with the idling set bolt.

(b) In this state, measure the minimum speed to ensure that it is within the specification.

(c) If the measurement is out of the specification, use the set bolt for adjustment.

(2) Maximum Speed

(a) Operate the adjusting lever to the position where it touches the full load set bolt.

(b) In this state, measure the maximum speed to ensure that it is within the specification.

(c) If the measurement is out of the specification, adjust with full load set bolt.

NOTE: Ensure that the engine does not stall or hunting does not occur even when the adjusting lever is abruptly returned from the full load to idling position. If any unusal condition is present, adjust within the specification range.

5-4 - RLD Type Governor

5-4-1 - Disassembly

For disassembly of parts with an encircled number, see following items.

NOTE:

1. Item numbers 27, 28, 37 to 42 are not to be disassembled normally.

2. Item number 29, Plug, cannot be reused.

3. Do not remove the governor housing unless removal is necessitated for correction of oil leaks, parts replacement, etc. Before removing the housing, use Holder (special tool) to separate the camshaft from the tappet.

(1) Loosen adjusting lever clamp nut and remove governor cover.

NOTE: Ready a receiver to receive lubricant that will come out when removing the governor cover.

(2) Lock the camshaft in position and remove the round nut that clamp flyweights.

Using Extractor (special tool), remove the flyweights together with the key.

(3) Remove the snap ring and torque cam.

NOTE: These parts should be removed only when replacement seems necessary from wear in torque cam shaft pin hole and shaft pin.

5-4-2 - Inspection and Reassembly

(1) When installing the start spring to the connecting link, insert the spring hook into the connecting link hole, working from above.

(2) Installation of Shifter

With the sleeve fully pressed against the flyweight slider, vary adjusting shim thickness to obtain the dimension shown at right for the distance between the governor housing end face (seating surface with governor cover) and the shifter pin hole center.

Install the shifter assembly to the tension lever.

Type of Adjusting Shim (Thickness)

0.2, 0.3, 0.4, 0.5, 1.0, 1.5 mm

(3) Installation of Governor Shaft

Position the governor cover inside wall flush with the guide screw end (L = approx. 14 ±0.5 mm) and tighten the lock nut.

Install the spring seat to governor spring with its step facing toward spring.

From the outside of governor cover, slightly screw the nut into the threads in governor shaft end face to lock in position.

(4) Installation of Governor Cover Assembly

During installation of governor cover, ensure that the governor shaft can be moved in the fore-and-aft direction by hand.

(a) If the sliding motion is not smooth, slightly back off the clamp bolt, rock the governor cover, and tighten the bolt when the center of governor shaft is aligned with that of shaft hole in the cover (where shaft moves smoothly).

If the shaft still binds, disassemble again.

(b) After the governor cover has been installed, slack the governor spring set tension.

Ensure that the following control rack position is obtained when the control rack is pused to the governor from the pump drive end with the adjusting lever operated to the full load position without restricting the adjusting lever and full load set lever (by the stopper bolt).

Control rack movement: 9.5 to 21 mm

Then, check to see if the control rack smoothly reaches to the following maximum point when it is released.

Injection pump maximum lift: 21 mm (Control rack entire stroke)

5-4-3 Adjustment after Reassembly

Adjust the relationship between the pump speed and the rack position as follows, in accordance with the specified governor performance curve.

As the governor performance curves vary with each specification, see Service Information separately published.

(1) Preparation

(a) Install the injection pump to the pump tester and feed injection pump oil to the governor and cam chambers.

(b) Remove the idling spring and governor shaft lock nut.

(c) Loosen the full load set bolt, idling set bolt, and full load set bolt.

(d) Installation of adjusting device

Make the lever run in parallel with the supporter at the portion indicated in illustration. Set "0" on the dial at the lever pointer and tighten the knurled lock nut under the handle.

Using the adjusting nut, position and fit the pin on the handle shaft into the center hole in the governor adjusting lever shaft. Then, fit the pin on the lever into the adjusting lever rod connecting hole.

With the handle loosened, turn the lever and make sure that the control rack slides smoothly.

(e) Control rack 0 position setting

1) Install Measuring Device (special tool) at the end of control rack.

2) Secure the adjusting lever near the idle position.

3) Press the governor shaft against the pump housing wall, increase speed up to 2 000 to 2 200 rpm, and push the control rack to the governor. Then, set 0 position on the dial indicator.

NOTE: Turning the injection pump at the speed specified above is extremely important. Failure to do so does not allow obtaining the 0 position even with the control pinion pushed hard and can damage governor linkage.

(f) Control rack locking

1) With the adjusting lever at idle position, increase the pump speed up to 500 to 600 rpm. Then, move the adjusting lever to the full speed position.

Next, set the control rack at full load position plus approx. 3 mm with the full load set bolt. Under these conditions and with the rack fixed at the specified position, make required adjustments.

2) Before moving the adjusting lever to full speed position, make sure that the pump speed is increased to 500 to 600 rpm with the lever at idle position.

3) The torque cam adjusting nut must be locked in position with the lock screw.

(2) Governor Spring Contact Adjustment

(a) Idling lever position temporary setting

Using the adjusting device, temporarily fix the adjusting lever at a position in contact with the idling set bolt.

Tighten the idling set bolt to obtain the rack position R₁ with pump speed N₁.

Then, read the adjusting device dial and make sure that the adjusting lever angle is within the specified angle range.

(b) Idling spring adjustment

With the adjusting lever at idle position, tighten the idling screw so that the rack position becomes R₂ when pump speed is N₂.

(c) Governor spring contact adjustment

Set the adjusting lever in contact with the idling set bolt and adjust the governor shaft so that the rack position becomes R₅ when the pump speed is N₅. Then, secure the shaft with lock nut.

Under this condition, decrease the pump speed to ensure that the speed is N₄ when rack position is up to R₄. Then, increase the pump speed and ensure that the rack reaches 0. If these specifications are not met, replace the governor spring.

(d) Idling adjustment

Adjust with the idling set bolt so that the rack position becomes R₃ when pump speed is at N₃ with the adjusting lever placed in contact with the idling set bolt.

After adjustment, make sure that the adjusting lever angle at idle is within the specified range.

(3) Full Load Rack Position Setting

(a) Full load control rack position adjustment

Place the full load set lever in contact with the full load set bolt, and temporarily secure the set bolt so that pump speed is slightly lower than N₇ preventing pump from turning in the governor control speed range.

Adjust tightening of full load set bolt so that the rack position becomes R₆ when pump speed is kept at N₆ with the full load set lever at full load position.

(b) Torque cam adjustment

Lock the adjusting lever at full load position.

Adjust the torque cam adjusting nut with Special Wrench (special tool) so that the rack is positioned at R₈ with pump speed at N₈.

Ensure that the rack position becomes R₆ when the speed is reduced down to N₆. Make also sure that the torque cam moves within the adjusted nominal value range with varying pump speeds.

If the rack position varies, it means that the torque cam is improperly adjusted. Make readjustment, or if it is impossible, replace the torque cam.

Check the fuel injection rate with the lever set at the adjusted nominal value. If adjustment is required, adjust full load set bolt and torque cam with the adjusting nut.

(4) High Speed Control Pump Speed Adjustment

Lock the adjusting lever at a position in contact with the full speed set bolt.

With the pump speed increased, adjust full speed set bolt so that the speed becomes N₇ when the rack starts to be pulled from R₇. Then, secure with the bolt.

Then, make sure that the adjusting lever operating angle is within the specified range by checking with the adjusting device dial.

Gradually increase the pump speed, and ensure that the pump speed becomes N₉ when the rack is pulled to R₉. Make also sure that further increasing the pump speed causes the rack to be pulled to 0.

(5) Smoke Set Assembly Operating Limit Check

Set the pump speed slightly above idle N₂ and lock the adjusting lever at a position to obtain rack position R₂.

Make sure that the rack position is beyond R₁ when pump is stopped and that the rack is positioned at the limit position when the adjusting lever is placed in the full position.

NOTE: Decreasing the pump speed with the adjusting lever at full position does not permit obtaining the smoke set rack position at startup.

(6) Black Smoke Prevention Limit Check

Set the adjusting lever at idle position and decrease the pump speed down to N₁₀. Then, ensure that the smoke set is not activated when the adjusting lever is placed in the full position.

Gradually increase the pump speed and make sure that the speed N₁₁ allows the rack to leave R₁₀, at which the smoke set is obtained, to move in the decreasing direction.

(7) Sealing

With all adjustments completed, seal the governor as follows.

NOTE: After adjustment of no-load minimum and maximum speeds, seal the sections marked with *.

5-4-4 Inspection and Adjustment of No-load Minimum and Maximum Speeds

Perform the following checks after the engine has been sufficiently warmed up.

(1) Minimum Speed

Make sure that the adjusting lever is in contact with the idling set bolt. Then, measure to ensure that the minimum speed is within specification.

If the speed is out of specification, adjust with the idling set bolt.

(2) Maximum Speed

If the maximum speed is not within specification when the adjusting lever is in full load position (where it is in contact with full speed set bolt), adjust with the full speed set bolt.

NOTE:

1. Never change the fixed position of full load stopper bolt.

2. Ensure that the engine does not stall or hunt when the adjusting lever is quickly shifted from the full load to idle position. If abnormal condition is evident, adjust within the specification.

5-5 RU Type Governor

5-5-1 Disassembly

For disassembly of parts with an encircled number, see following items.

NOTE: Do not remove the governor housing unless removal is necessitated for correction of oil leaks, parts replacement, etc. In case of removal, use Tappet Insert (special tool) to separate the camshaft from the tappet.

(1) Loosen the stopper bolt to slack the governor spring. Then remove the governor cover.

(2) Remove the spring seat, outer spring, inner spring, and governor sleeve.

To remove governor sleeve, turn it 90°.

(3) Remove the stopper bolt, adjusting lever set, adjusting lever shaft, arm assembly, and collar.

NOTE: Do not remove the bearing bushing and oil seal unless replacement is necessary.

(4) To remove the camshaft bushing, use Puller (special tool).

(5) Remove the stop screw, full speed adjusting lever, shaft, and governor spring.

NOTE: Remove oil seals only for replacement.

5-5-2 Inspection and Reassembly

(1) Install the governor shaft and thrust bearing into the governor housing. Then, mount the governor housing in the pump housing.

NOTE:

1. The governor shaft lock nut must be tightened to the specified torque.

2. Ensure the oil hole faces up in the governor shaft where installed.

Increase or decrease the number of shim plates to obtain the specified clearance between the thrust bearing and governor gear. The clearance should be up to specification if A - B is 5.85 to 6.35 mm which is the clearance plus the dimension C.

If the clearance is too large, the governor gear will come into contact with the back of the flyweight and if too small, the governor gear will come into contact with the thrust bearing.

(2) Replace the snap ring with a new one and, at installation, ensure that its side with no edge faces toward the slip disc.

Make also sure that the dimension A in snap ring is 3 mm or less.

Select the adjusting shim between the snap ring and slip disc by measuring the slip torque.

(3) Measurement of Slip Torque

Mount the gear assembly onto Slip Torque Measuring Device (special tool) to measure the slip torque.

If the specification is not met, vary shim thickness or replace the slip disc.

(4) Mount the gear assembly onto camshaft: fit a pin into the camshaft bushing hole to align it with the keyway in camshaft, and tighten the round nut to specification.

(5) Secure the arm onto the adjusting lever shaft with the stopper bolt.

When tightening the stopper bolt, ensure the gap A becomes 0.5 to 1.5 mm.

(6) Install the governor sleeve, inner spring, outer spring, and spring seat.

NOTE:

1. Fit the floating lever pin into the governor sleeve groove.

2. Ensure the correct installed direction of governor sleeve and spring seat.

(7) Installation of Floating Lever

Install the flanged bushing to the outside of governor (where nut is provided), and ensure that the shackle moves smoothly.

Install the shackle pin as shown.

Move the top of floating lever through the entire stroke of control rod (in fore-aft direction) to ensure that it moves smoothly.

(8) Install the governor cover. At installation, use the locating pin provided on the governor housing for proper alignment.

(9) With the damper spring capsule temporarily tightened, install the return spring.

After installation, make adjustments and tests with a tester.

5-5-3 Adjustment after Reassembly

Adjust the relationship between the pump speed and rack position as follows, in accordance with the specified governor performance curve.

As the governor performance curves vary with each specification, see Service Information separately published.

NOTE: Fill the governor chamber and pump cam chamber with engine oil.

(1) "0" Position Setting of Control Rack

(a) Mount Rack Position Measuring Device (special tool) on the control rack.

(b) Mount the adjusting lever angle scale onto the test stand.

(c) Loosen the idling set bolt and remove the damper spring.

(d) Turn down the full speed set bolt a certain amount to give tension to the governor spring.

(e) Push the control rack all the way and regard the position as 0 of the Rack position Measuring Device (special tool).

(2) Control Rack Stroke Check

Make sure that the control rack returns by approximately 18 mm by the start spring force when it is released. If the rack does not return so much, check the rack as well as floating lever for motion.

Make also sure that the entire stroke of control rack is 21 mm when the adjusting lever is operated.

(3) Low Speed Control Adjustment

(a) Tighten the idling set bolt so that the control rack is positioned at R₁ when the pump runs at N₁₀.

Secure with lock nut when the specified rack position is obtained.

(b) Measure to check if the control rack is positioned at R₉ with the pump speed at N₂.

If the rack is not positioned at R₉, remove the governor cover and adjust with the shim plate (for outer idling spring) inside the governor sleeve. If the specification is not met, increase the number of shim plates; if it is exceeded, decrease the number of plates.

(c) Make sure that the control rack is positioned at R₇ when pump runs at N₃.

(d) Make measurement to check if the control rack is at R₅ with the pump speed at N₅.

If the rack is not at R₅, adjust by increasing or decreasing the number of shim plates (for inner idling spring) inside the governor sleeve.

(e) Ensure that the control rack is positioned at R₂ when the pump runs at N₇.

(f) Ensure that the control rack is positioned at or beyond R₁₂ when the pump speed is at N₁.

(g) Make sure that the hysteresis is 0.3 mm or below.

(4) Intermediate Speed Control Adjustment

(a) Give adequate tension to governor spring and place the adjusting lever in the full load position.

(b) Adjust the full load stopper bolt so that the control rack is positioned at R₁₀ when pump runs at N₉.

After adjustment, secure with lock nut.

Make also sure that the control rack does not move when pump runs at N₁₁.

(c) Ensure that the control rack is positioned at R₁₁ when the pump runs at N₆.

(d) Make sure that the adjusting lever angle at full load position is within specification.

(5) High Speed Control Adjustment

(a) Place the adjusting lever in the full load position.

(b) Adjust the full speed set bolt so that the control rack starts to be pulled when the pump runs at N₁₂, and secure with lock nut.

(c) Make sure that the rack is positioned at R₈ when the pump speed is increased up to N₁₃.

(d) Ensure that the hysteresis is 1 mm or below.

(6) Damper Spring Adjustment

(a) With the cap nut removed from the damper spring, adjust the adapter capsule so that the control rack is positioned at R₆ when the pump runs at N₅. After adjustment, tighten the lock nut and mount the cap nut.

(b) Increase the pump speed and ensure that the control rack is positioned at R₄ when pump speed reaches N₇. Ensure also that the control rack is positioned at R₃ or below when the pump runs at N₈.

(c) Make sure that the damper spring control hysteresis is 1 mm or below.

(7) After the governor has been adjusted, place the adjusting lever in the idle position and run the pump at 300 rpm. Pull the control rack 11 mm and release to make sure that it takes 10 seconds or less for the rack to return to its original position.

(8) Adjustment for Adaptation to Engine

With the adjusting lever at full load position and pump running at the specified speed, ensure that the fuel injection rate of all cylinders is within specification.

If the rate deviates slightly from the specification, adjust with the full load stopper bolt.

(9) Stopper Bolt Adjustment

With the adjusting lever at full load position, adjust so that the control rack is positioned at R₁₂ ±0.1 mm when the pump runs at N₄.

(10) Stop Lever Adjustment

Place the adjusting lever in the idle position and run the pump at the specified speed.

Pull the stop lever in the stop direction and make sure that the specified rack position and fuel injection rate are obtained.

(11) Sealing

After all adjustments have been made, seal the governor as follows.

NOTE: After adjustment of no-load minimum and maximum speeds, seal the sections marked with *.

5-5-4 Inspection and Adjustment of No-load Minimum and Maximum Speeds

Perform the following checks after the engine has been sufficiently warmed up.

(1) Minimum Speed

Make sure that the adjusting lever is in contact with the idling set bolt. Then, measure to ensure that the minimum speed is within specification.

If the speed is out of specification, adjust with the idling set bolt.

(2) Maximum Speed

If the maximum speed is not within specification when the adjusting lever is in full load position (where it is in contact with full speed set bolt), adjust with the full speed set bolt.

NOTE:

1. Never change the fixed position of full load stopper bolt.

2. Ensure that the engine does not stall or hunt when the adjusting lever is quickly shifted from the full load to idle position. If abnormal condition is evident, adjust within the specification.

5-6 MZ Type Governor

In case of models with MZ type governor, remove the venturi as illustrated.

5-6-1 Disassembly and Inspection

For disassembly of parts with an encircled number, see following items.

NOTE: Remove the governor housing only in case of oil leaks or replacement of parts. For removal use Tappet Insert (special tool) to separate the camshaft from the tappet.

(1) Remove the diaphragm housing and remove the main spring and main spring shim.

NOTE: Store the main spring shim separately in order to prevent its loss and mixing with others.

(2) Remove the split pin that couples the diaphragm with the control rack and then remove the diaphragm.

NOTE: Handle the diaphragm carefully to prevent damage. Keep it free from engine oil or gas oil.

5-6-2 Reassembly

(1) Install the stop lever on the stop lever shaft observing the following requirement.

When the stopper bolt is tightened to the specified torque, the nominal value should be maintained for the gap A. If the gap exceeds the specified value when the stop lever is replaced with a new one, ream the hole with a taper pin reamer.

NOTE: Never ream to such an extent that the gap cannot be maintained.

Use a hand taper pin reamer conforming to the following illustration.

(2) Install the diaphragm to the control rack.

Coat the diaphragm with 2 to 4 drops of Denso Diaphragm Oil before installation.

5-6-3 Adjustment after Reassembly

Adjust the relationship between negative pressure and rack position as follows, in accordance with the specified governor performance curve.

As the governor performance curves vary with each specification, see Service Information separately published.

NOTE:

1. Supply oil to the governor chamber and the injection cam chamber.

2. When changing negative pressure, first change widely and then set to the specified level and read off the gauge after the pressure has stabilized.

(1) Fix the idling capsule at non-operating position.

(2) Control Rack "0" Position Setting

Install Rack Position Measuring Device (special tool) on the control rack and using a screwdriver, push the pump control rack pinion as far as it goes in the noninjection direction (toward the governor) and make this position as the "0" position.

(3) Air Tightness Test

With the negative pressure in the negative pressure chamber set to 500 mmAq, measure the time taken for the pressure to reach 480 mmAq, which should be 10 seconds or more.

If not air tight, tighten the housing again or check the diaphragm.

(4) Adjusting Main Spring

(a) Adjusting initial rack position

Adjust the full-load spring capsule so that the rack position becomes R₁ at negative pressure P₁.

(b) Check that the rack position is R₁ at negative pressure P₂ and it is R₂ at negative pressure P₃. If not, adjust the number (thickness) of shims of the main spring.

Shim Thickness

0.5, 1.0, 2.0, 3.0 mm

NOTE: After adjustment, check the initial rack setting again.

(5) Adjusting Idling Spring Capsule

(a) Adjusting initial rack position

Adjust the idling spring capsule using Idle Adjust Wrench (special tool) so that the rack position becomes R₄ at negative pressure P₅.

(b) Check that the rack position is R₃ at negative pressure P₄.

If not, readjust the initial rack position within limits of nominal values.

(6) Adjusting Adaptation to Engine

Check that the pump speed is as specified and that the total injection amount at negative pressure is within the range of nominal values.

If not, adjust the full-load spring capsule.

(7) Sealing

On completion of all adjustments, seal the governor as follows.

NOTE: After adjustment of no-load minimum and maximum speeds seal the sections marked with *.

5-6-4 Inspection and Adjustment of No-load Minimum and Maximum Speeds

Perform the following checks after the engine has been sufficiently warmed up.

(1) Minimum Speed

Make sure that the venturi lever is in contact with the idling set screw. Then, measure to ensure that the minimum speed is within specification.

If the speed is out of specification, adjust with idling set screw.

(2) Maximum Speed

Operate the venturi lever to the position where it is in contact with full speed set screw. Then, measure to ensure that the maximum speed is within specification.

If the speed is out of specification, adjust with full speed set screw.

NOTE: Ensure that the engine does not stall or hunt when the venturi lever is quickly shifted from the full position to idle position.

5-7 Feed Pump

5-7-1 Disassembly, Inspection and Reassembly

1 Priming pump

2 Eye bolt

3 Valve support

4 Spring

5 Check valve

6 Eye bolt

7 Gauze filter

8 Plug

9 Spring

10 Piston

11 Push rod

12 Snap ring

13 Tappet

14 Housing

For reassembly, reverse the order of disassembly.

NOTE: Know the trouble spots thoroughly by making tests before disassembly.

5-7-2 Test and Adjustment

5-8 Automatic Timer

5-8-1 SCZ Type Automatic Timer <4D31, 4D30, DR (Nippondenso Products)>

(1) Removal

(a) Loosen the round nut with Socket Wrench (special tool).

(b) Using Timer Extractor (special tool), remove the auto timer from the injection pump.

(2) Disassembly and Inspection

For disassembly of parts with an encircled number, see following items.

For disassembly of parts with an encircled number, see following items.

Raise the injection pump gear while turning it in the direction to compress the timer spring. Then remove the injection pump gear.

NOTE: Use care not to let the timer spring spring out.

(3) Reassembly

(a) With the flyweights mounted on the timer hub, install the injection pump gear in the direction of the illustration.

(b) Put the timer spring, spring seat <4D30, DR> and shim together and insert them between the timer hub pin and the injection pump gear pin.

(c) While turning the injection pump gear in the direction to compress the timer spring, fit the injection pump gear pin into the curved surface of the flyweight.

(d) Check the spring for installed condition.

(e) Install the shim and circlip

Then, measure the thrust clearance of the injection pump gear.

If the clearance is out of specification, adjust with shims.

(4) Installation

Mount the auto timer, aligning it with the camshaft key. Then, tighten the round nut to the specified torque using Socket Wrench (special tool).

(5) Test and Adjustment

Whenever the auto timer is disassembled, its advance angle must be measured with the manufacturer's measuring instrument and readjusted.

To adjust the advance characteristics, add or reduce the adjusting shims or replace the spring.

To reduce the advance angle, increase the shim thickness.

Shim Thickness

4D30, 4D31: 0.5, 0.6, 0.7, 0.8, 0.9, 1.0 mm

DR: 0.1, 0.2, 0.3, 0.5, 1.0 mm

5-8-2 SCDM Type Automatic Timer <4D31-T (Diesel Kiki Products)>

(1) Removal

(a) Using Socket Wrench (special tool), loosen the round nut.

(b) Using Timer Extractor (special tool), remove the auto timer from the injection pump.

(2) Disassembly and Inspection

(3) Reassembly

(a) After the flyweight assembly has been installed to the timing flange, position the flyweight pins as shown, with reference to the keyway in the timing flange, and install the larger and smaller cams.

(b) Install the flange, aligning it with the hole in the smaller cam and ensuring that its alignment mark (identation) is positioned on the same side as the timing flange keyway.

(c) Put the timing flange and flange closely tied together and ensure that the clearance between the flange and shim is up to specification. If the clearance is out of specification, replace shim.

Shim Thickness

0.10, 0.12, 0.14, 0.16, 0.18, 0.9, 1.1, 1.3, 1.5, and 1.7 mm

(d) Vary shim to obtain the specified clearance between the cover and shim

Shim Thickness

0.10, 0.12, 0.14, 0.16, 0.18, 0.9, 1.1, 1.3, 1.5, 1.7 mm

NOTE: When measuring the clearance, closely contact the cover and flyweight.

After adjustment, install snap ring.

(e) After the timer characteristic adjustments have been completed (see next items), install the gear with its alignment mark "0" lined up with the timing flange keyway or alignment mark on the flange.

Then tighten six bolts diagonally to the specified torque.

(4) Installation

Mount the auto timer onto the camshaft, aligning it with the camshaft key. Using Socket Wrench (special tool), tighten the round nut to specification.

(5) Test and Adjustment

Whenever the auto timer has been disassembled, its advance angle must be measured and adjusted with the manufacturer's measuring device.

To adjust the advance characteristics of the auto timer, add or reduce the adjusting shims or replace the spring.

To reduce the advance angle, increase the shim thickness.

Shim Thickness

0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0 mm

5-9 Injection Nozzle

5-9-1 Removal and Installation

<4D31, 4D31-T>

1 Bridge

2 Injection nozzle

3 Nozzle tip gasket

<4D30, DR>

1 Injection nozzle

2 Nozzle tip gasket

To remove and reinstall the injection nozzle, use Socket Wrench and Handle (special tools).

If the nozzle tip gasket is hard to remove because of seizure, use Gasket Pliers (special tool).

NOTE: Cover pipes, injection nozzle, and injection pump to prevent entry of dust and dirt. If the injection nozzle is removed, provide adequate means to prevent entry of dust into the cylinder.

5-9-2 Disassembly

<4D31, 4D31-T>

1 Retaining nut

2 Nozzle

3 Needle valve

4 Packing

5 Pressure pin

6 Spring

7 Washer

8 Nozzle holder

NOTE: Make sure that the combination of the nozzle and needle valve is not changed.

<4D30, DR>

1 Nozzle holder

2 Shim

3 Pressure spring

4 Retaining pin

5 Distance piece

6 Needle valve

7 Nozzle

8 Retaining nut

NOTE: Make sure that the combination of the nozzle and needle valve is not changed.

5-9-3 Cleaning and Inspection

(1) Cleaning

After cleaning the nozzle with gas oil, remove carbon deposits with Nozzle Cleaning Tool (special tool). Proceed as follows.

(a) Remove the needle valve from the nozzle and clean the needle valve with the needle valve cleaning wood piece.

(b) Insert, while turning, a cleaning needle into the injection orifice of the nozzle to remove carbon.

Use first a cleaning needle having smaller diameter than that of injection hole and then finish with following:

<4D31, 4D31-T>

0.28 mm [Valve opening pressure 17.7 MPa (180 kgf/cm²)] 0.30 mm [Valve opening pressure 21.6 MPa (220 kgf/cm²)]

<4D30, DR>

1.0 mm

(c) Remove carbon from the oil pool and valve seat of the nozzle body. <Except 4D31, 4D31-T>

(d) To remove burnt and hardened carbon, use Fuso Carbon Remover.

(2) Inspection

Clean and immerse the nozzle in gas oil, slide the needle valve, and ensure that it moves smoothly.

Next, pull up the needle valve vertically about 1/3 of its entire stroke and check if it falls under its own weight. If it does not fall, replace the nozzle.

5-9-4 Reassembly

NOTE:

1. Never touch the sliding surfaces of the needle valve by hand.

2. When replacing the nozzle tip with a new one, remove the seal peel (synthetic resin film) and move the needle valve in nozzle in a clean gas oil to completely remove the anti-rust oil.

5-9-5 Test and Adjustment

(1) Injection Pressure

(a) Install a nozzle tester to the nozzle.

(b) Operate the nozzle tester to inject several times. This allows the tester to be bled of air.

(c) Operate the nozzle tester at the specified speed. Then, vary shims to obtain the specified injection pressure.

Shim Thickness

<4D31, 4D31-T>

0.95 to 1.25 mm in 0.05 increments 1.275 to 1.775 mm in 0.025 increments 1.80 to 2.15 mm in 0.05 increments

<4D30, DR>

1.00 to 1.95 mm in 0.05 increments

A 0.05 mm variation in shim thickness varies the injection pressure by 0.49 MPa (5 kgf/cm²).

(d) With a correct shim selected, recheck the injection pressure.

NOTE: Never let yourself exposed directly to the atomized fuel injected from the nozzle.

(2) Spray Condition

When adjusting the pressure with a nozzle tester, check also for clogged injection orifices, spray condition, and fuel leaks from the orifices. Replace the nozzle if defective.

<4D31, 4D31-T>

Good

1 Evenly sprayed from five injection orifices

2 Even and symmetrical

Poor

3 Asymmetrical

4 Branched

5 Thin

6 Irregular

<4D30, DR>

Good

1 Correct spraying angle and direction

Poor

2 Wide spraying angle

3 Off axis line

4 After-drip

5 Branched

6 Stepped

7 Swiveling

(3) Fuel Tightness Test

Mount a nozzle, that has been adjusted to start injection at the specified pressure, to the nozzle tester and slowly increase the pressure to the test pressure. Keeping this condition, check for fuel leaks from the bottom of the nozzle. The nozzle is in good condition if there is no leak.

5-10 Fuel Filter

5-10-1 Removal and Installation

1 Fuel feed hose

2 Fuel filter

To remove the element, use Filter Wrench (special tool).

NOTE:

1. For installation, tighten the element by hands.

2. After installation, run the engine and check for fuel leaks.

5-10-2 Disassembly, Inspection and Reassembly

1 Fuel filter head

2 Element

5-11 Water Separator

5-11-1 Disassembly, Inspection and Reassembly

1 Drain plug

2 Ring nut

3 Case

4 Baffle plate

5 Float

6 Head

7 Connector bolt

8 Joint

If the red float in the translucent case rises to the level of the red line marked on the outer circumference of the case, loosen the drain plug to discharge water.

It is not necessary to completely remove the drain plug as water is discharged gradually through the groove of the loosened plug.

NOTE: After draining, tighten firmly the drain plug before bleeding the fuel system.