Service Information and Use of 8T5300 Engine Timing Indicator Group{0782} Caterpillar

137 mm (5.4") and 158.8 mm (6.25") Bore Engines, 3500 Family Spark Ignited Engines

Introduction

The 8T5250 Engine Timing Indicator is a test instrument that can be used to measure fuel injection timing for a diesel engine, or spark plug firing on spark ignition engines, while the engine is in operation. The timing indicator can also be used to check the operation of the automatic timing advance unit, on engines that are so equipped.

Electrical power to operate the unit comes either from the vehicle electrical system, or, if there is no electrical system available, from two 6 volt lantern-type batteries.

The 8T5300 Engine Timing Indicator Group must be used with an 8T5301 Diesel Timing Adapter Group on a diesel engine, or, a 6V9060 Spark Timing Adapter Group on spark ignition engines.

In the 8T5300 Engine Timing Indicator Group, the fuel line transducer connects to the fuel injection pump bonnet of No. 1 cylinder, and is then connected to the engine timing indicator. The fuel line transducer can then send a signal to the 8T5250 Engine Timing Indicator when fuel is injected into No. 1 cylinder.

For spark ignition engines, a spark transducer connects to the primary coil for No. 1 spark plug, and sends a signal to the 8T5250 Engine Timing Indicator when the spark plug fires.

Most current production Caterpillar diesel engines are equipped with a static timing pin hole in the flywheel housing, and a corresponding hole in the flywheel. When the two holes are in alignment, the piston for No. 1 cylinder is at top center position. A bolt can then be put through the hole in the flywheel housing and threaded into the hole in the flywheel to lock the engine at the top center (TC) position for static timing.

For dynamic timing, an adapter and a TDC magnetic transducer are installed in the flywheel housing timing pin hole (see the installation procedure in this instruction). When the transducer is connected to the 8T5250 Engine Timing Indicator, it sets up a constant magnetic field around the end of the transducer and the flywheel.

As the flywheel turns (engine running) and the timing hole in the flywheel passes the end of the transducer, a change in the magnetic field causes the transducer to send the TC signal to the 8T5250 Engine Timing Indicator.

In diesel engine operation, fuel is injected before No. 1 piston reaches top center position. In spark ignition engine operation, the No. 1 spark plug fires before No. 1 piston reaches top center.

The 8T5250 Engine Timing Indicator receives the fuel injection, or spark, signal first, then measures the time it takes to receive the top center (TC) signal. The timing indicator then converts these two signals, and the time between them into engine rpm, and engine timing in degrees before top center (BTC).

NOTE: After the 8T5250 Engine Timing Indicator receives the fuel injection or spark signal, the first signal that the magnetic transducer sends will be considered the No. 1 cylinder top center signal. It is then, important for the flywheel to be free of any other holes or large nicks between the point of injection (or spark plug firing) and top center (TC).

As an example, if the specifications indicate that fuel should be injected into No. 1 cylinder @ 15° before top center, the flywheel must be free of holes or large nicks in the area of the flywheel that is at least 15° before top center (BTC).

For correct operation, the timing indicator must receive the TDC signal within 60° flywheel rotation after it receives the fuel injection signal, or, the spark signal. If timing is actually after top center, i.e., the TC signal occurs before the injection pulse, the timing indication will be incorrect, and be a steady number between 60° and 90°.

Glossary

TC: Top Center.

RPM (rpm): Revolutions Per Minute.

°BTC: Degrees Before Top Center.

DEG: Degrees.

Features (characteristics) of the 8T5300 Engine Timing Indicator Group

Adaptability:

This timing indicator group is usable on engines that have a TDC bolt hole in the flywheel housing, as found on 3300 and 3400 Family Engines, and on 3500 Family Spark Ignited Engines. It can also be used on 1100, 3100 and 3208 Family Engines that have a timing hole in the engine front cover.

All other Caterpillar (non-unit injector) engines can be timed with the 8T5300 Engine Timing Indicator Group, if the engine is modified to permit a way to get a TDC signal.

Accuracy:

The timing indicator group can be used, and has the accuracy, to check the dynamic (engine running) timing of the entire fuel system. It can also be used to check the operation of the timing advance mechanism, on those engines that are so equipped.

Operation:

There are no restrictions on engine speed or load, so timing can be checked during the actual operation of an engine. The digital readouts (number indications) are liquid crystal displays (LCD) that have long life and high accuracy.

Fuel System Connection:

A fuel line injection transducer "tee" adapter is installed in the injection line, AT THE FUEL PUMP. The injection line will be moved only about 8 mm (.3"), which will keep bending of fuel lines to a minimum. Installation time is also held to a minimum. DO NOT ATTEMPT TO USE THE 6V4950 FUEL LINE SPEED PICKUP. IT IS NOT DESIGNED FOR THIS APPLICATION.

Timing Indicator Connection:

The connecting cables for the timing indicator group are 18 feet (6 m) long. If necessary, the serviceman can have the timing indicator connected and read it in the operator's station. All electrical connections can be connected in only one way, the correct way.

Power Supply:

The vehicle electrical system, (12V, 24V or 32V) either positive or negative ground, is the source of power for the timing indicator group. There are no internal batteries. For those engines that do not have an electrical system for a power supply, two 6 Volt lantern-type batteries, wired in series, can be used as a power supply for the timing indicator group.

Troubleshooting:

The design of the timing indicator group is such that any problem with the operation of the unit can be found quickly and easily, whether the problem is with the indicator, either signal transducer, or with the power supply.

Serviceability:

Using the information given in this instruction, the single-printed circuit board used in this unit can be repaired in MOST electronic repair shops. The two cables used with the 8T5300 Engine Timing Indicator Group, have the same part number as cables that are used with other Caterpillar diagnostic tools, so they are already available through the Caterpillar Parts Department.

8T5300 Engine Timing Indicator Specifications

Range of Timing:

0-60 Engine crankshaft degrees (before top center ONLY).

Range of Tachometer:

250-4000 rpm.

Accuracy of Indicator Group:

Within the specified operating temperature ranges - after specified system warmup:

Speed:

± 12 rpm.

Timing with 8T5301 Diesel Timing Adapter Group: ± .2 engine degrees typical: ± .4° MAX [± .4° MAX includes a ± .2° interchangeability error (difference in transducer output) that is possible when one injection transducer is exchanged for another injection transducer.]

Timing with 6V9060 Spark Timing Adapter Group: ± .2 engine degrees typical: ± .4° MAX.

NOTE: This considers instrumentation error only.

Power Needed:

11 to 40 Vdc at 0.1 Ampere - power directly from any 12, 24 or 32V electrical system. If vehicle electrical system is not available, two 6V lantern-type batteries can be used instead.

Temperature Range of Ambient Air During Operation:

Timing Indicator: -18° to +60°C (0° to 140°F)

Fuel Injection Transducer: -18° to +100°C (0° to -212°F)

TDC Transducer: -40° to 115°C (-40° to +240°F)

Spark Timing Adapter: -18° to + 82°C (0° to 180°F)

System Warmup:

After installation of the 8T5300 Indicator Group, and after the engine has reached operating temperature, run the engine at approximately one-half throttle for an ADDITIONAL 8-10 minutes BEFORE taking any timing measurements.

Operating Position of Indicator:

Any position.

Weight of Timing Indicator Group:

4 kg (8.8 lbs)

Size of Carrying Case:

470 × 368 × 127mm (18 1/2 × 14 1/2 × 5").

Cable Lengths:

6 m (18 feet).

Components of 8T5300 Engine Timing Indicator Group

1/41/8 Parts included in the 8T5300 Engine Timing Indicator Group are as follows: 1. 6V7145 Case. 2. 8T5250 Engine Timing Indicator (incl. 6V3080 Base). 3. 8T3253 Packing Set. 4. 5P7366 Cable Assem. (Power). 5. 8K4644 Fuse (five). 6. 6V3093 Transducer Adapter, " NPTF. 7. 6V2199 Transducer Adapter, " NPTF. 8. 6V2197 Magnetic Transducer (TDC) 114 mm (4.5") long. 9. 5P7362 Cable. 10. 6V6045 Case.

Additional components (service parts) not shown for the 8T5300 Indicator Group are as follows: 8T0887 Connector Assem.; 8T1005 Display Unit; 6V4179 Digital Voltmeter Integrated Circuit; 6V4177 Calibration Check/Operate Switch; 6V4178 Power Switch; SEES5686 Title Decal (on outside of carrying case) and SEES5687 Instruction Decal (inside lid of carrying case).

NOTE: Tools needed to check timing on a diesel engine are different from those needed to check timing on a spark ignition engine. A separate adapter group is available for use on each type of engine (diesel or spark ignition), and each adapter group is used with the 8T5300 Engine Timing Indicator Group. These adapter groups, and some optional accessories that are available, are shown on the pages that follow:

Components of 8T5301 Diesel Timing Adapter Group

1. 5P7437 Adapter. 2. 5P7436 Adapter. 3. 6V7910 Transducer^* (fuel line). 4. 5P7435 Adapter (tee). 5. 6V3016 Washer. 6. 6V2198 Cable.

Components of 6V9060 Spark Timing Adapter Group

1. 8T5259 Transmitter. 2. 8T5257 Receiver. 3. 8T5260 Fiber Optic Cable. 4. 1U5524 Adapter Cable. 5. 8T5258 Coil Adapter Cable.

Optional Accessories

1. 8T5184 Magnetic TDC Transducer [89 mm (3.5") long]. 2. 8T5185 Magnetic TDC Transducer [178 mm (7.0") long].

Installation, Connection and use of 8T5300 Engine Timing Indicator Group on Diesel Engines (Engines That Have a Static Timing Bolt Hole in the Face of the Flywheel or a Timing Bolt Hole in the Front Cover)

NOTE: Always check timing indicator group calibration before leaving the shop. Make any adjustments an/or corrections that are necessary.

NOTE: Use the 8T5301 Diesel Timing Adapter Group with the 8T5300 Engine Timing Indicator Group to check timing on a diesel engine.

NOTE: The 8T-5300 Engine Timing Indicator Group with the adapter groups operates identical to the earlier 6V3100 Engine Timing Indicator Group.

1. Connect the 5P7366 Cable (power) to POWER connector (A), and put the POWER REVERSE ON-OFF Switch (B) in the OFF position.

2. At the other end of the power cable, connect one of the connectors to the machine frame for a good electrical ground (DO NOT connect to the battery negative terminal), then connect the other connector to the power source (12, 24 or 32 volts DC).

NOTE: DO NOT USE THE 8T5300 ENGINE TIMING INDICATOR GROUP WHILE A 6V2100 MULTITACH IS CONNECTED TO THE SAME BATTERIES. The multitach must be disconnected before using the 8T5300 Engine Timing Indicator Group. Switching pulses from the multitach power supply can cause incorrect RPM and DEG readings on the 8T5250 Engine Timing Indicator.

3. Put the POWER REVERSE ON-OFF Switch (B) in the position (up or down) that will cause a display (indication) at RPM and DEG [locations (C) and (D)] and also cause the NO TDC signal light at location (E) to go on. While the indicator group becomes warm, make the remainder of the necessary connections. See the information that follows.

4. Loosen the fuel line nut at the fuel injection pump, for number one cylinder. Slide the nut up and out of the way.

If the engine is equipped with double wall fuel injection lines, remove the number one fuel injection line and install a standard number one fuel line. THIS IS FOR TIMING PROCEDURE ONLY.

After the timing procedure is completed, install the original number one fuel line on the engine.

NOTE: NEVER install the injection transducer at the fuel nozzle. Actual timing at this location is retarded by 7-10° from the timing measured at the fuel injection pump.

NEVER use the clamp-on fuel line transducer from the 6V4950 Injection Line Speed Pickup Group to operate the 8T5300 Engine Timing Indicator Group. Even though the connectors look identical, they will not connect correctly.

5. Lift the end of No. 1 fuel line far enough to install 5P7436 Adapter (1), from the 8T5301 Diesel Timing Adapter Group, on injection pump bonnet (2). Install adapter (1) far enough so bottom edge (F) of opening (G) (in the side of the adapter) is approximately even with top surface (H) of the bonnet.

6. ALWAYS install a 6V3016 Washer (J) in 5P7435 Adapter (3), then install adapter (3) on 6V7910 Injection Timing Transducer (6).

7. Put 5P7435 Adapter (3) through opening (G) of adapter (1) in the position shown. Now put fuel line (4) in position on tee adapter (3) and install and tighten 5P7437 Adapter Nut (5). When adapter (3) and fuel line (4) are in alignment with pump bonnet (2), tighten adapter nut (5) to a torque of 40 ± 7 N·m (30 ± 5 lb ft).

NOTE: To make it easier to tighten adapter nut (5) on the number one injection pump bonnet of a 3208 Engine, use a modified 5P5195 Fuel Line Wrench. See the topic entitled Modification of 5P5195 Fuel Line Wrench and 5P331 Crowfoot Wrench in this instruction.

NOTE: Use a 9S7354 Torque Wrench with a 2P5494 Crowfoot Wrench to tighten injection transducer (6) in adapter (3) to 19 ± 1 N·m (170 ± 10 lb in).

NOTE: There must be no fuel leakage at either the pump bonnet, or the fuel injection timing transducer, if accurate readings are to be obtained. A leak that can not be stopped can be an indication of a damaged 5P7435 Adapter caused by an incorrect installation procedure.

8. Remove the plug from the timing bolt hole. In the illustration that follows, the timing bolt hole is shown in the flywheel housing.

NOTE: Some engines have two timing bolt holes in the flywheel housing, one on each side of the engine. Use either timing bolt hole for this procedure. For 1100, 3100 and 3208 Family Engines, the timing bolt hole is in the engine front cover, not in the flywheel housing.

9. Install the correct transducer adapter (7) (either 6V2199 or 6V3093) from the 8T5300 Engine Timing Indicator Group. Tighten the adapter just a little more than finger tight.

10. Select the correct length TDC transducer (8) (8T5184, 8T5185 or 6V2197). Use the procedure that follows for transducer installation:

* Put a 2D6392 O-ring Seal on the probe end of the TDC transducer. (A small amount of clean engine oil on the O-ring seal will let it slide easier on the probe.)

* Push transducer (8) through adapter (7) until it comes in contact with the flywheel or the gear. Move the O-ring seal down the probe so it is against adapter (7).

* Pull transducer (8) out slowly and measure from the O-ring seal to get the correct dimension as follows, then tighten the adapter nut finger tight to hold the transducer in position.

(a) .5 ± .25 mm (.020" ± .010") from the face of the gear for 1100, 3100 and 3208 Engines.

(b) 2 ± 1 mm (.080" ± .040") from the face of the flywheel for all other engines.

NOTE: On those engines where the TDC transducer is installed into the flywheel housing, the injection timing transducer can be installed in the fuel line of the injection pump that is at TDC, 360° in the firing order from the No. 1 cylinder. This alternate position is permissible only for those engines that use the flywheel housing for the TDC transducer. Do not use this alternate position for the injection timing transducer on engines, such as the 3208, that use the front cover for the TDC transducer.

On these engines, the camshaft gear is the source for the TDC signal for the timing indicator, instead of the flywheel. Because of the difference in rotational speed, the TDC signal pulse will be incorrect.

If the TDC transducer is too close to the face of the flywheel or gear, it will not send an acceptable signal to the timing indicator group. As an example, if the end of the transducer is too close to the face of the camshaft gear on a 3208 Engine, it will read the rough surface of the gear instead of the timing hole. In this position, the timing indication can be constant and acceptable at low idle speed, but as engine rpm is increased, the timing indication will change rapidly and will not be accurate.

NOTE: For engines that are equipped with an Allison CT700, HT700, 5000 and 6000 Transmission or a TC500 Series Torque Converter, see the topic entitled Correction of Timing Indicator Reading (when necessary) in this instruction.

11. Use the 5P7362 Cable and the 6V2198 Cable to connect magnetic transducer (8) and injection transducer (6) to connections (P) and (Q) of timing indicator (9).

12. Check for correct operation and accuracy of the timing indicator according to the procedure that follows:

* The reading at location (C) (RPM) and (D) (DEG) must each be zero. If they are not, check the calibration of the timing indicator.

* Move switch (R) to the CALIBRATE position. The engine speed reading at location (C) must be 2000 ± 30 rpm. The engine timing reading at location (D) must be 32.0 ± .2 DEG. (If the readings are different than given, it is an indication that there is a need for calibration of the unit.)

* Release switch (R). Engine timing checks and/or measurements can now be made. There are no limits on load or speed, but, operation at FULL LOAD SPEED for an extended period of time can cause shorter life for the injection transducer.

13. Start the engine. Readings and/or indications will be as follows:

* NO TDC SIGNAL - light must go out.

IMPORTANT: After the engine has reached operating temperature, run it at approximately one-half throttle for an additional 8-10 minutes before taking any timing measurements. This is to make sure that all air is purged from the 6V7910 Injection Timing Transducer. [It may take 15-30 minutes to get an rpm reading on an engine with low injection pressure (such as a 3208).] If reducing the throttle to LOW IDLE speed causes the rpm display to go to zero, that is an indication that air is still in the transducer.

* RPM - reading must show engine speed.

* DEG - reading must show engine timing degrees.

Correction of Timing Indicator Reading (when necessary)

1. As an example, some Engines have Allison CT700. HT700, 5000 and 6000 Transmissions or TC500 Series Torque Converters. In these applications, a 6N9829 Flywheel adapter Group is used to connect the transmission or torque convertor to the engine.

2. The 6N9667 Flywheel Assembly (1) in the adapter group has twelve 25.4 mmØ (1.00" Ø) holes (2) that are almost in the same radius as timing pin holes (3) and (4). When the 8T5300 Engine Timing Indicator Group is used to check engine timing in these applications, it is possible that the transducer will read holes (2) instead of the timing pin hole. For this reason, an adjustment must be made to the timing reading, to find the correct timing for the engine.

NOTE: Reference to left side and right side of the engine is as seen when looking forward from the flywheel end of the engine. The arrow at location (C) shows the direction of crankshaft rotation. Locations (D) and (E) are approximate points of fuel injection.

3. On most engines, the TDC transducer can be installed in a hole on the left side, or the right side of the flywheel housing. To determine engine timing for these engines, a different timing correction factor must be used, according to which timing hole, (3) or (4), is used.

4. If the transducer is installed in the timing hole on the left side of the flywheel housing, the timing reading will be retarded by approximately 7.6° because the transducer incorrectly senses hole (A) as top center, instead of timing hole (3). [Timing hole (3) is the correct hole.]

5. If the transducer is installed in the timing hole on the right side of the flywheel housing, the timing indicator group will show the correct timing reading until fuel system timing advances to approximately 22.4°. At that point, the timing reading will drop to 0° because the transducer incorrectly reads hole (B) as top center, instead of timing hole (4). As the fuel system timing continues to advance, approximately 22.4° must be added to the timing reading to get the correct engine timing.

When pin timing the engine on its left side, the pin can slide into any of the 25.4 mm (1.00") holes. For correct timing, it must be installed in the threaded timing hole.

Use of 6V9145 Timing Adapter Group to Adapt 8T5300 Engine Timing Indicator Group to 158.8 mm (6.25") Bore Engines and Older Engines That do not Have a Top Center Pickup Hole

Parts of the 6V9145 Timing Adapter Group are as follows: 1. 6V9142 Drill Bit 6.4 mm (.250"). 2. 6V9141 Center Punch. 3. 6V9143 Transducer Adapter.

1. Disconnect the engine starting system.

2. Remove timing cover (4) from the flywheel housing.

3. Remove timing (5), then put 6V9143 Transducer Adapter (3) in the timing pin hole. Tighten the nut on the adapter, as shown, until the adapter fits firmly (finger tight) in the timing pin hole.

NOTE: If necessary, replacement O-rings are available for 6V9143 Transducer Adapter. Use 2D6392 O-ring Seal (small inner O-ring seal) and/or 6M5062 O-ring Seal (large outer O-ring seal).

4. Slide 6V9141 Center Punch (2) through adapter (3) until it almost touches flywheel (6).

NOTE: Make sure that center punch (2) is straight and not at an angle. If the center punch is at an angle (crooked), loosen the nut on adapter (3), align the center punch so it is straight, then tighten the adapter nut.

5. Use an engine turning tool or a pry bar to turn the flywheel until top center mark (A) for No. 1 cylinder is in alignment with the point on center punch (2).

NOTE: The flywheel has two holes (B) that are 180° apart. Check to make sure that there are no holes (B), or any other large holes in this flywheel surface area that are within 30° before the No. 1 cylinder TC mark. Any hole in this area will cause a retarded timing indication.

6. Use a hammer as shown, to strike the end of center punch (2), and make a mark on the flywheel to indicate the No. 1 TC location. Remove center punch (2).

7. Put the 6V9142 Drill Bit in an electric drill, then slide the drill bit into the adapter and align it with the center punched hole, as shown. Drill a hole (C) in the flywheel, approximately 3.0 mm (.125") deep.

8. Remove the drill and drill bit, then turn the flywheel just far enough to be sure the new hole (C) or any other hole is not in alignment with adapter (3).

9. Put TDC transducer (7) into adapter (3) as shown. Push the transducer in until it touches the flywheel, then pull it back out until the end is 2 ± 1 mm (.080" ± .040") from the flywheel.

10. Connect the engine starting system (disconnected in step 1); connect the transducer to the 8T5250 Engine Timing Indicator and do the timing procedure.

11. After the timing procedure is completed, remove TDC transducer (7) from adapter (3). Put 6V9141 Center Punch (2) in adapter (3), loosen the adapter nut, and wiggle (move from side to side and up and down) center punch (2), to loosen and remove adapter (3). Install the timing pin and timing pin cover.

Adapting 8T5300 Engine Timing Indicator Group for Use on D348 Engine in D10 Tractor

1. Remove flywheel timing pin cover (1) from the flywheel housing.

2. Use the dimensions shown to make a 8.3 mm (.328")Ø hole at location (A), then make 1/8"-27 NPTF threads all the way through the hole. Install the cover on the flywheel housing and install 6V2199 Adapter (2) in hole (A).

3. Select the correct length TDC transducer (3) (8T5184, 8T5185 or 6V2197). Use the procedure that follows for transducer installation:

Put a 2D6392 O-ring Seal on the probe end of the TDC transducer. (A small amount of clean engine oil on the O-ring seal will let it slide easier on the probe.)

Push transducer (3) through adapter (2) until it comes in contact with the flywheel or the gear. Move the O-ring seal down the probe so it is against adapter (2).

Pull transducer (2) out slowly and measure from the O-ring seal to get the correct dimension as follows, then tighten the adapter nut finger tight to hold the transducer in position.

* 2 ± 1 mm (.080" ± .040") from the face of the flywheel.

4. Connect the TDC transducer to the 8T5300 Engine Timing Indicator Group and do the timing procedure.

NOTE: After the timing procedure is finished, remove transducer adapter (2) from cover (1), then install a 1/8"-27 NPTF plug in hole (A).

Installation, Connection And Use Of 8T5300 Engine Timing Indicator Group On Spark Ignited Engines (Engines That Have A Static Timing Bolt Hole In The Face Of The Flywheel, Or A Timing Bolt Hole In The Front Cover)

Always check the calibration of the timing indicator group and make any necessary adjustments and/or corrections before leaving the shop.

NOTE: The 6V9060 Spark Timing Adapter Group must be used with the 8T5300 Engine Timing Indicator Group to check timing on spark ignition engines. To use the 8T5300 Engine Timing Indicator Group on a spark ignition engine, each cylinder of the engine must have an individual coil.

1. Connect 5P7366 Cable (power) to POWER connector (A), and put the POWER REVERSE ON-OFF Switch (B) in the OFF position.

2. At the other end of the power cable, connect one of the connectors to the machine frame for a good electrical ground (DO NOT connect to the battery negative terminal), and connect the other connector to the power source (12, 24 or 32 volts DC).

NOTE: DO NOT USE THE 8T5300 ENGINE TIMING INDICATOR GROUP WHILE A 6V2100 MULTITACH IS CONNECTED TO THE SAME BATTERIES. The multitach must be disconnected before using the 8T5300 Engine Timing Indicator Group. Switching pulses from the multitach power supply can cause incorrect RPM and DEG readings on the 8T5250 Engine Timing Indicator.

3. Put POWER REVERSE ON-OFF Switch (B) in the position (up or down) that will cause a display (indication) at RPM and DEG [locations (C) and (D)] and also cause the NO TDC signal light at location (E) to go on. While the indicator group becomes warm, make the remainder of the necessary connections. See the information that follows.

4. Connect 8T5258 Coil Adapter Cable (1) to 8T5259 Transmitter (2). (Both items are part of 6V9060 Spark Timing Adapter Group.)

5. Connect the leads of 8T5258 Coil Adapter Cable (1) directly to primary (low voltage) side (F) of the No. 1 cylinder ignition coil as shown.

NOTE: On an engine that has integral shielded ignition coils, disconnect coil adapter cable (1) that goes to No. 1 cylinder, and connect 8T5259 Transmitter (2) in line using the two connectors (3) and (4).

NOTE: For an engine that is equipped with integral shield ignition coils and Altronic magnetos, disconnect coil adapter cable (1) that goes to No. 1 cylinder, and connect 8T5259 Transmitter (2) to 1U5524 Adapter Cable (6). Disconnect the cable from the primary (low voltage) ignition coil terminals of the No. 1 cylinder. Connect 1U5524 Adapter Cable (6) between the ignition coil and cable (G).

6. Connect end (H) of 8T5257 Receiver (5) to INJECTION OR SPARK TRANSDUCER connection (l) on the 8T5250 Engine Timing Indicator.

7. Install the correct TDC transducer adapter (either 6V2199 or 6V3093) from the 8T5300 Engine Timing Indicator Group. Tighten the adapter just a little more than finger tight.

8. Select the correct length TDC transducer (8T5184, 8T5185 or 6V2197). Use the procedure that follows for transducer installation:

Put a 2D6392 O-ring Seal on the probe end of the TDC transducer. (A small amount of clean engine oil on the O-ring seal will let it slide easier on the probe.)

Push the transducer through the adapter until it comes in contact with the flywheel or the gear. Move the O-ring seal down the probe so it is against the adapter.

Pull the transducer out slowly and measure from the O-ring seal to get the correct dimension as given below, then tighten the adapter nut finger tight to hold the transducer in position.

* .5 ± .25 mm (.020" ± .010") from the face of the gear for 1100, 3100 and 3208 engines.

* 2 ± 1 mm (.080" ± .040") from the face of the flywheel for all other engines.

9. An exception to the TDC transducer installation procedure given above is if the engine is running (operating) at the time of the timing check. For this condition do the following:

Show/hide table

To avoid personal injury, DO NOT do the procedure that follows if there are moving parts in the area around the TDC transducer.

* With the TDC transducer connected to the 8T5300 Engine Timing Indicator Group, and the timing indicator group connected to the engine through the 6V9060 Adapter Group, and reading rpm; carefully insert the TDC transducer through the transducer adapter until a stable (steady) reading is observed on the DEG display. Finger tighten the adapter nut to hold the transducer in position.

10. Check timing at the normal operating speed. When checking timing on a spark ignited engine, the timing indicator will display actual timing. THERE IS NO PORT EFFECT on a spark ignited engine.

Modification of 5P0331 Crowfoot Wrench and 5P5195 Fuel Line Wrench for use on 3208 Engines

1. Modify sections (A) and (B) of a 5P0331 Crowfoot Wrench (1), to the dimensions shown above. Use a drill bit, the same size as hole (2), and an electric drill to drill hole (2) through the other side of wrench (1).

2. Remove the original crowfoot wrench (3) from extension (4) of the 5P5195 Fuel Line Wrench.

3. Use the original spring pin (5) to assemble the modified 5P0331 Crowfoot Wrench (1) on extension (4) as shown. Drive spring pin (5) IN so it is in both sides of wrench (1).

Interpretation of Dynamic Timing on a Diesel Engine that does not have a Mechanical Timing Advance Unit

NOTE: Use a copy of Form SEHS8140, Dynamic Timing Chart, to make the graph for the timing check. This worksheet is available in pads of 50 sheets, and can be ordered in the normal manner from the Miscellaneous Order Division.

The 8T5300 Engine Timing Indicator Group, with 8T5301 Diesel Timing Adapter Group, can measure dynamic timing at any engine speed or load. If an engine does not have a mechanical timing advance unit, measure the timing at only one engine speed.

Dynamic timing (A) is affected by "port effect" (B). Port effect (B) is the pressure wave that is formed by the rapid movement of the injection pump plunger through the fuel. This pressure wave causes fuel injection to begin before the fuel supply port is closed by the plunger. As a result, port effect is in itself an advance.

Dynamic timing (A), therefore, can be calculated by adding port effect (B), to static timing (C).

NOTE: On all engines with the new scroll fuel system, port effect is approximately .2° for each 100 rpm. For all other engines, port effect is .1° for each 100 rpm.

Interpretation of Dynamic Timing on a Diesel Engine that has a Timing Advance Unit

Two types of mechanical advance units are used on Caterpillar-built engines. One unit has a constant rate of advance from its starting speed to its ending speed. The second unit has two rates of advance. One rate occurs from the starting speed to the intermediate speed, and a second rate occurs from the intermediate speed to the ending speed.

When operating correctly, the mechanical advance should effect a smooth change in the dynamic timing of an engine. This gradual change should occur during both acceleration and deceleration. For this reason, it is necessary to measure the dynamic timing at 100 rpm intervals between low idle speed and high idle speed to confirm the operation of the advance.

Dynamic timing (A) is affected by port effect (B) on engines with mechanical advance in the same way as explained previously for engines without mechanical advance. Port effect is a timing advance in addition to the mechanical advance.

Dynamic timing (A) on engines with mechanical advance can be calculated at any given engine speed. To do this, port effect (B) is added, along with mechanical advance (D), to static timing (C). See the illustration that follows.

NOTE: On all engines with the new scroll fuel system, port effect is approximately .2° for each 100 rpm. For all other engines, port effect is .1° for each 100 rpm.

The illustration above is used to illustrate the example that follows for an engine that has single rate advance.

Static timing = 16°

Advance = 5°

Starting speed = 1500 rpm

Ending speed = 2800 rpm

Low idle = 650 rpm

High idle = 3065 rpm

1. Idle Speed: 650 rpm

Port Effect (0.1° × 6) = .6°

Static Timing = 16.0°

Mechanical Advance = 0.0°

Calculated Dynamic Timing = 16.6°

2. Starting Speed: 1500 rpm

Port Effect (0.1° × 15) = 1.5°

Static Timing = 16.0°

Mechanical Advance = 0.0°

Calculated Dynamic Timing = 17.5°

3. Ending Speed: 2800 rpm

Port Effect (0.1° × 28) = 2.8°

Static Timing = 16.0°

Mechanical Advance = 5.0°

Calculated Dynamic Timing = 23.8°

4. High Idle: 3065 rpm

Port Effect (0.1° × 31) = 3.1°

Static Timing = 16.0°

Mechanical Advance = 5.0°

Calculated Dynamic Timing = 24.1°

The illustration above is used to illustrate the example that follows for an engine that has two rates of advance.

Static timing = 11°

First Advance = 6°

Starting speed = 1400 rpm

Second Advance = 4°

Intermediate Speed = 1700 rpm

Ending speed = 2200 rpm

Low idle = 650 rpm

High idle = 2290 rpm

1. Low Idle: 650 rpm

Port Effect (0.1° × 6) = .6°

Static Timing = 11.0°

Mechanical Advance = 0.0°

Calculated Dynamic Timing = 11.6°

2. Starting Speed: 1400 rpm

Port Effect (0.1° × 14) = 1.4°

Static Timing = 11.0°

Mechanical Advance = 0.0°

Calculated Dynamic Timing = 12.4°

3. Intermediate Speed: 1700 rpm

Port Effect (0.1° × 17) = 1.7°

Static Timing = 11.0°

Mechanical Advance = 6.0°

Calculated Dynamic Timing = 18.7°

4. Ending Speed: 2200 rpm

Port Effect (0.1° × 22) = 2.2°

Static Timing = 11.0°

Mechanical Advance (first plus second) = 10.0°

Calculated Dynamic Timing = 23.2°

5. High Idle: 2290 rpm

Port Effect (0.1° × 23) = 2.3°

Static Timing = 11.0°

Mechanical Advance = 10.0°

Calculated Dynamic Timing = 23.3°

When checking the dynamic timing on an engine that has a mechanical advance, Caterpillar recommends that the serviceman calculate and graph the dynamic timing on a worksheet like Form SEHS8140, a copy of which is shown at the back of this instruction. This worksheet is available in pads of 50 sheets, and can be ordered in the normal manner from the Miscellaneous Order Division.

After the timing values are calculated and plotted, check the actual dynamic timing using the 8T5300 Engine Timing Indicator Group and the 8T5301 Diesel Timing Adapter Group. To do the timing check the serviceman must operate the engine from LOW IDLE to HIGH IDLE and from HIGH IDLE to LOW IDLE. He must record the dynamic timing at each 100 rpm, at the specified speeds during both acceleration and deceleration, then plot the results on the worksheet.

E. Calculated Timing. F. Measured Timing.

E. Calculated Timing. F. Measured Timing.

The two timing graphs shown here indicate timing advance that is not acceptable. In the first graph, timing advance did not begin until several hundred rpm beyond the specified starting speed. Timing then suddenly advanced to within specifications. This graph indicates a mechanical problem with the advance unit.

In the second graph, the timing advance did not begin until several hundred rpm beyond the specified starting speed, but then advanced smoothly to the specified timing. This graph can be an indication of an assembly problem, such as an incorrect spring on one, or both of the weights, or an incorrect adjustment of START OF ADVANCE.

A graph that does not show stable timing within 0.1° to 0.2° in the timing advance speed range, is normally an indication of interference between the springs and weights in the timing advance unit. This interference is often the result of bent springs or burrs. Also, if there is an indication of retarded timing after timing advance begins, this is usually caused by worn timing gears, and/or a worn fuel injection pump drive coupling.

If a change of 100 rpm in engine speed causes the engine timing indication to retard by several degrees at higher engine speeds, the cause can be a false TDC signal. (The TDC transducer senses an incorrect hole, dent, or some other imperfection on the surface of the flywheel or timing gear, instead of the correct timing hole.) To see if this is the problem, move the TDC transducer OUT, so it is a few thousandths farther away from the surface of the flywheel or timing gear. Do the timing procedure again.

Plotting Dynamic Timing Data Using the Fuel Setting and Related Information Microfiche

The acceptable tolerance for dynamic (operating) fuel injection timing, for engines with or without a timing advance unit, can be determined from the data available in the "Fuel Setting and Related Information" microfiche library (SBFY1108). The specified fuel system data must be plotted (recorded) on a Dynamic Timing Chart, Form SEHS8140.

The actual dynamic fuel injection timing of an engine, when measured with the 8T5250 Timing Indicator and plotted on the timing chart, must fall within the borders of this tolerance. If it does not, an adjustment or repair may be necessary.

Two examples are shown of plotting Fuel System Data on Dynamic Timing Charts. In each example, the dynamic timing tolerance is constructed from the minimum and maximum values of the timing degrees and engine speed at each test point provided in the Fuel System Data section of the Fuel Setting and Related Information microfiche. The minimum and maximum value tolerance includes both the engine tolerance and the measuring tool tolerance.

EXAMPLE 1. Fuel System Data from "Fuel Setting and Related Information" microfiche 0T4858.

The fuel system data shown above in example 1 is for a 571G Pipelayer with a 3306 Engine, 0T4858. This example does not have a timing advance unit. The dynamic tolerance is shown plotted in Example 2 that follows.

Dynamic Timing Chart

EXAMPLE 2: Dynamic Timing Tolerance for 0T4858. A. Dynamic Timing Tolerance. B. Reference RPM Window. C. Stop RPM Window.

The 0T4858 Specification shows an acceptable timing from 20.5 to 23.5 degrees (Minimum and Maximum) at first test speed, Ref. RPM (B), of 970 to 1030 RPM. The two timing values are plotted at both speed values, making four data points. The four data points are connected to form a window (see Example 2).

For an engine with no timing advance unit, a second window is constructed in the same manner at the second test speed, Stop RPM (C). The extreme limits of the two windows are connected to form dynamic timing tolerance (A) (see Example 2).

The slope of the line that connects Reference RPM Window (B) to Stop RPM Window (C) is the result of "Fuel Injection Port Effect" that is included in the Fuel System Data.

EXAMPLE 3. Fuel System Data from "Fuel Setting and Related Information" microfiche 0T4442.

Example 3 shows Fuel System Data for a 3406B Truck Engine with a New Scroll Fuel System, 0T4442, that has a timing advance unit. The new Scroll Fuel System has a port effect of 0.2° per every 100 engine rpm. This value is included in the Fuel System Data. All other engines have 0.1° port effect per every 100 rpm and this is also included in the Fuel System Data.

Dynamic Timing Chart

EXAMPLE 4: Dynamic Timing Tolerance for 0T4442. D. Dynamic Timing Tolerance. E. Reference RPM Window. F. Start RPM Window. G. Stop RPM Window. H. Start of Advance Must Occur Within This Window. J. End of Advance Must Occur Within This Window.

Example 4 is the plotted example of engine timing for an engine with a timing advance unit. Dynamic timing tolerance (D) will have three windows instead of two as in Example 1. Four data points are located and connected, as in Example 1, for Reference RPM, Start RPM, and Stop RPM. This forms three windows. The extreme limits of all the windows are connected to form dynamic timing tolerance (D) as shown in Example 4.

The slope of the lines, from Reference RPM Window (E) to Start RPM Window (F) is the result of fuel injection Port Effect. The slope of the lines from Reference RPM Window (E) to Stop RPM Window (G) is the result of fuel injection Port Effect, plus the timing advance unit. The slope of these lines can not be changed unless the timing advance unit or its components are changed, however, the start and stop point can be changed on New Scroll Fuel Systems. The start and stop point can not be changed on other fuel systems.

There are a few engines that are equipped with compound timing advance units. These engines are identified by the Mid RPM test point. If there is a value listed in the Fuel System Data Timing specification, a fourth window is plotted in the same manner as Examples 2 and 4. When the extremes of the four windows are connected the slope of the lines from theReference RPM window to the Mid RPM window will be different than the slope of the lines from the Mid RPM window to the Stop RPM window. The slope of these lines is controlled by fuel injection Port Effect and the timing unit components, and is not adjustable.

If the measured fuel injection timing passes through each window of the dynamic timing tolerance, and does not fall outside the line connecting the windows, no adjustment or repair is required. If the measured timing is outside the Reference RPM window, an appropriate adjustment to the static timing will be necessary to bring the measured timing to within the acceptable tolerance.

If the measured dynamic timing is within the Start RPM window but outside the Stop RPM window, an adjustment or repair of the timing advance unit is required. The change in the slope of the measured dynamic timing indicates the start, mid and stop timing advance and should occur within the appropriate window. If not, an adjustment or repair of the advance unit is required. Consult the appropriate Service Manual for the repair or adjustment procedure necessary to achieve the correct dynamic timing.

Diagnosing Results of Dynamic Timing Check

1. If there is NO port effect measured as engine speed is increased, it is possible that the injection pump bonnet is moving under its retainer bushing, because of fuel injection pressures. If the bonnet does move in this way, it can relieve part of the pressure build-up during fuel injection. The result of this will be "no port effect measurement".

2. If the timing indication at reference rpm is less than specified, and retards even more as engine speed increases, or, if timing does not advance as much as expected, check to sure the fuel line transducer is installed at the fuel pump bonnet and not at the fuel nozzle.

The fuel injection signal travels to the fuel nozzle at a fixed speed, so, if the fuel line transducer is located at the fuel nozzle, as engine speed increases, the fixed speed (time delay) will give an indication of a timing retard instead of a timing advance.

3. If the engine timing reading is STEADY at reference rpm (whether or not it is the correct timing does not matter in this condition) but, during a smooth speed increase, the timing at a given speed becomes erratic or even retards, look for a loose fuel pump drive, worn spline drive, or worn timing gear.

Timing Tolerances

The normal tolerance for a mechanical timing advance unit is ± 1°. For example, an advance of 7° to 9° is acceptable for a specified timing of 8°. This tolerance, however, applies only to the dynamic timing from the ending speed to the high idle speed. This timing tolerance can be different from one engine model to another, so always refer to the Service Manual Specifications or the Fuel Setting and Related Information microfiche, Form SBFY1108.

The timing advance must start within ± 100 rpm of the specified starting speed, and it must stop within ± 100 rpm of the specified ending speed. Because of manufacturing tolerances in the timing advance units, starting and ending speed can vary from unit to unit. This is not critical and should not be interpreted as such.

What is important, however, is that the timing advance must occur smoothly throughout the specified speed range. The timing is set and operating correctly when the actual dynamic timing indications shown are within the specification range, and the angle of change is approximately the same as the specification from low idle speed to high idle speed.

The acceptable timing tolerance when using the 8T5300 Engine Timing Indicator Group is ± 1.5°. This tolerance consists of a 1.3° tolerance on static timing, based on engine manufacturing, and 0.2° tolerance for the instrument. This ± 1.5° total tolerance for the indicated timing is applicable throughout the speed range on engines without mechanical advance.

The ± 1.0° tolerance mentioned previously for the mechanical advance must be added to the ± 1.5° tolerance for the indicated timing between the advance ending speed and the high idle speed. Thus, engines with mechanical advance have a tolerance of ± 2.5° at high idle.

Dynamic Timing on Spark Ignited Engines

Check dynamic timing on a spark ignited engine with the engine at normal operating speed. There is no timing advance mechanism on a spark ignited engine, however, due to the operating characteristics of magnetos, timing can vary from 1° to 3° when it is checked at low idle instead of at normal operating speed.

NOTE: There is no port effect on spark ignited engines.

Troubleshooting the 8T5300 Engine Timing Indicator Group Installation

Calibration Procedure

To make sure that 8T5300 Engine Timing Indicator Group (1) has good accuracy, check its calibration at a minimum of every six months. The timing indicator will also need calibration if:

* It does not show 2000 ± 30 RPM at (A) and 32.0 ± .2 DEG at (B), when CALIBRATION CHECK-OPERATE Switch (C) is in the CALIBRATION CHECK position.

* Reading is different than (000) at either location (A) or (B).

NOTE: With no input signal at (D) or (E), the reading at RPM location (A) must show three zeros (000). If four zeros (0000) show, it is an indication of a POSSIBLE need for calibration of the unit. THIS ERROR ONLY is not reason enough to do a complete calibration procedure. It is also not necessary to do a complete calibration procedure if the reading at DEG location (B) has a decimal point as shown, (00.0) in addition to the three zeros.

All calibrations can be done with the use of a small screwdriver, a frequency counter and a Caterpillar Digital Multimeter (DMM). If a frequency counter and a digital multimeter are not available, a 5P9698 Calibrator can be used as a replacement, but it is probable that the interval will be shorter until calibration is again necessary.

1. Remove six screws (2), along the edge, then lift panel (3) from its case.

2. Put power to the 8T5250 Timing Indicator for two minutes or more to get it warm, then use one of the procedures that follow, according to the calibration tools that are to be used.

Calibration Using a Frequency Counter

1. Connect a frequency counter from TP10 to TP1 (ground).

2. Adjust R204 (OSC. FREQ. ADJ.) so the counter reads 12,000 ± 5 Hz. Disconnect the frequency counter.

3. Connect a Caterpillar Digital Multimeter (DMM) (or equivalent multimeter) from TP17 to TP1 (ground). Adjust the DMM to the DCV-200 mV scale.

4. Adjust R312 (RPM BALANCE) so the DMM reads + 0.1 mV.

NOTE: If a DMM is not available, turn R312 CCW until the fourth "zero" shows (normally only three zeros) at RPM, location (A). Then turn R312, one to one and one-fourth turns CW.

5. Connect the multimeter from TP23 to TP1, and set it to the DCV-200 mV scale.

6. Adjust R327 (DEG. Balance) so the DMM reads + 0.1 mV. Disconnect the DMM.

NOTE: If a DMM is not available, turn R327 CCW until the decimal point shows at DEG, location (B). Now turn R327, one-half turn CW.

7. Hold the CALIBRATION CHECK-OPERATE switch in the CALIBRATION CHECK position.

8. After there is stability in the necessary readings at locations (A) and (B), adjust R313 (RPM CALIBRATE) so the reading at location (A) is exactly 2000. To do this, turn R313 (CW and then CCW) to change the reading at location (A) to 1990, and then 2010. Now, adjust R313 so it reads exactly 2000 at location (A).

9. Adjust R328 (DEG CALIBRATE) so the reading at location (B) is 32.0. To do this, turn R328 (CW and then CCW) to change the reading at location (B), then adjust it to read exactly 32.0.

10. Release the CALIBRATION CHECK-OPERATE switch.

Calibration Using a 5P9698 Calibrator

1. Connect a Caterpillar Digital Multimeter (DMM) (or similar tool) from TP17 to TP1 (ground) set it to the DCV-200mV scale.

2. Adjust R312 (RPM BALANCE) so the DMM reads + 0.1 mV.

NOTE: If a DMM is not available, turn R312 CCW until the fourth "zero" appears (normally only three zeros) at RPM, location (A). Now turn R312, one to one and one-fourth turns CW.

3. Connect the DMM (or similar tool) from TP23 to TP1 and set it to the DCV-200mV scale.

4. Adjust R327 (DEG. BALANCE) so the DMM reads + 0.1 mV.

NOTE: If a DMM is not available, turn R327 CCW until the decimal point shows at DEG, location (B), then turn R327 one-half turn CW. Disconnect the DMM.

5. Use the large adapter plug to connect cable (1) of 5P9698 Calibrator (2) to the RPM CAL. INPUT jack of 8T5250 Timing Indicator (3) as shown. Adjust the calibrator to 25 Hz.

6. Adjust R313 (RPM CALIBRATE) so the reading at location (A) is exactly 3000. To do this, turn R313 CW and then CCW, so the reading at location (A) will be 2990 and then 3010, then adjust it to exactly 3000.

7. Disconnect calibrator cable (1), then turn calibrator (2) to OFF.

8. Hold the CALIBRATE CHECK-OPERATE switch in the CALIBRATION CHECK position.

9. Adjust R204 (OSC. FREQ. ADJ.) so the reading at location (A) is exactly 2000. To do this, turn R204 CW and then CCW so the reading at location (A) will be 1990, and then 2010, then adjust it to exactly 2000.

10. Adjust R328 (DEG CALIBRATE) so the reading at location (B) is 32.0. To do this, turn R328 (CW and then CCW) to change the reading at location (B), then adjust it to read exactly 32.0.

11. Release the CALIBRATION CHECK-OPERATE SWITCH.

Power Supply Adjustments (Adjust Without Injection Transducer Connected to Indicator)

1. Connect a Caterpillar Digital Multimeter (DMM) (or similar tool) from TP3 to TP1 (ground) and set it to the DCV20 scale. Adjust R104 (+ 8 V ADJ) until the DMM reads 8.00 ± .01 Volts.

2. To adjust the 2.830 Volts on TP4, (INJECTION SWITCH POINT ADJUST), use the following procedure. (The 6V3030 DMM can not measure this voltage as 2.830, but would instead show 2.83.)

(a) Connect a DMM from TP6 to TP1 (ground) and set it to the DCV2 scale. Measure this exact voltage and make a note of it. It should be + 1.500 ± .010 Vdc.

(b) Subtract the above "1.500" voltage from 2.830 Volts (Example: 2.830 (-) 1.502 = 1.328 Volts).

(c) Connect a DMM from TP4 (red lead) to TP6 (black lead). Adjust R105 (INJECTION SWITCH POINT ADJUST - shown as "INJECTION SWITCH PT" on PC board) until the DMM reads the exact voltage as determined in step (b) above.

8T5300 Engine Timing Indicator Group Component Check

Indicator Group Self-Check

The self-check ability is available, if needed, any time that power is sent to the timing indicator. An internal calibrator simulates (works the same as) an engine that is operating at 2000 rpm with 32.0° timing. When the CALIBRATION CHECK-OPERATE switch is in the CALIBRATION CHECK position, as shown, the injection transducer and TDC transducer are both electrically disconnected from the indicator (if their plugs are in the indicator) and the internal calibrator takes their place. This test will immediately let the user know the condition of the indicator.

If the internal calibrator and the indicator are within calibration limits, RPM, location (A), will show 2000 ± 30 and DEG, location (B), will show 32.0 ± .2°. Failure to get these readings is an indication of a need for calibration.

Also, with the CALIBRATION CHECK-OPERATE switch in the OPERATE position (with engine shut down, or all signal cables disconnected) each display should show three zeros. If RPM shows four zeros, and/or DEG shows a decimal, this is an indication that the indicator may soon need calibration. The recommendation for calibration is every six months.

Check of 5P7366 Power Cable

1. Use an 8T0500 or 8S4627 Circuit Tester or a Caterpillar Digital Multimeter (1) to check for continuity of each wire. This check should measure .000 ohms on the 2K ohm resistance scale.

2. Check for short circuits between the two conductors. This check should measure OL (infinite ohms) on the 2K ohm resistance scale as shown.

Check 5P7362 TDC Signal Cable

1. Use an 8T0500 or 8S4627 Circuit Tester, or Caterpillar Digital Multimeter (1) to check for continuity of the center conductor, and of shield (2).

2. Both checks should measure .00 ohms on the 2K ohm resistance scale.

3. Also check for a short between conductors. This check should measure OL (infinite ohms) on the 2K ohm resistance scale.

Check 6V2198 Injection Signal Cable (From 8T5301 Diesel Timing Adapter Group)

1. Use an 8T0500 or 8S4627 Circuit Tester, or a Caterpillar Digital Multimeter to check for each wire. Each check should measure .000 ohms on the 2K resistance scale.

2. This illustration shows the male connector end of the 6V2198 Cable. The female end is connected point-to-point with the male connector end.

3. Check for short circuits between each conductor. Each check should measure OL (infinite ohms) on the 2K ohm resistance scale.

Check of TDC Magnetic Transducer

1. Using a Caterpillar Digital Multimeter (DMM) (1), or a similar tool, check TDC transducer (2) and leads for continuity. The resistance should be 250 ± 40 ohms on the 2K ohm resistance scale. If the DMM reads OL (infinite ohms), the transducer needs replacement.

2. Check for a short circuit from the transducer shell to the phono plug center pin. If the DMM does not read OL (infinite ohms) on the 2m ohm resistance scale, replacement of the transducer is necessary.

Check of Injection Transducer (From 8T5301 Diesel Timing Adapter Group)

NOTE: This test is acceptable only if the temperature of the injection transducer is 19°C-30°C (67°F-87°F). If the transducer is warm, from use or any reason, a minimum of two hours will be needed to permit the transducer to become cool enough [19°C-30°C (67°F-87°F)] to do this test.

1. Remove the six sheet metal screws (1) from the front panel.

2. Remove the panel from its case and turn it face down. Use the 6V2198 Signal Cable to connect the 6V7910 Injection Transducer into INJECTION or SPARK TRANSDUCER Jack (A).

3. Connect power to the indicator.

4. Connect a ground wire from the transducer case to the negative terminal of the indicator power source. Using a Caterpillar Digital Multimeter (DMM) (or similar tool) on the 2VDC scale, measure the transducer output voltage as follows:

* Put red DMM probe (2) on the transducer pin 4 connection (green wire) marked J301-4 on the PC board.

* Put black DMM probe (3) on pin 3 (black wire) marked J301-3 on the PC board.

5. With no pressure application to the 6V7910 Transducer, the voltage between pins 3 and 4 should be between + 2.47 and + 2.53 Volts.

NOTE: To do the test in step 6 that follows, the threaded end of the 6V7910 Injection Timing Transducer will be installed into an adapter with 3/8"-24 threads. When the transducer is installed into the adapter, use a 6V3016 Washer to make contact between the transducer and the adapter.

Correct tightening of the transducer is important. Use a 9S7354 Torque Wrench with a 2P5494 Crowfoot Wrench, and tighten the transducer to 19 ± 1 N·m (170 ± 10 lb in) of torque.

6. Use a dead weight tester with at least 0.1% accuracy and put a pressure of 6900 kPa (1,000 psi) to the transducer. This pressure should cause the DMM to read + 2.83 ± .02 Volts for the 6V7910 Transducer.

7. For any 6V7910 Transducer that is not within the specifications given in step 6 and is still in warranty, send it to the Viatran Corporation. The address is given at the back of this instruction.

Check of 6V9060 Spark Timing Adapter Group - (Using Spark Ignited Engine)

1. Use a Caterpillar Digital Multimeter (DMM) (1) to check for continuity of each lead on 8T5258 Coil Adapter Cable (2). Set the Multimeter on the 2K ohm scale. Scale reading should be .00 with one multimeter probe connected to one lead of cable (2) and the other multimeter probe touching the correct socket on the connector. Do this for both cable leads. If both readings are not .00, replace the 8T5258 Cable.

2. Set multimeter (1) to the 2M ohm scale and connect a multimeter probe to each lead of 8T5258 Coil Adapter Cable (2). The DMM reading should be OL.

3. Now connect both leads of cable (2) with one DMM probe (3) and use the other probe to touch the metal MS connector shell (4). The DMM reading should be OL. If the reading is not OL, either repair or replace the cable. If cable (2) checks good, proceed to the next check as given in Step 4 that follows.

4. Connect an 8T5250 Engine Timing Indicator to the 6V9060 Spark Timing Adapter Group. Connect the 6V9060 Spark Timing Adapter Group to the primary coil on a spark ignited engine.

NOTE: If preferred, a function generator can be used instead of using the spark ignited engine. Refer to the topic entitled CHECKING THE 6V9060 SPARK TIMING ADAPTER GROUP WITH A FUNCTION GENERATOR AND FREQUENCY COUNTER in this instruction.

Make sure the 8T5250 Engine Timing Indicator is good and works correctly. If unsure, connect the engine timing indicator to an injection transducer from the 8T5301 Diesel Timing Adapter Group, and check timing indicator operation. (The TDC transducer does not have to be connected.)

5. Turn 8T5250 Engine Timing Indicator "ON" and start the engine. If the timing indicator gives a stable (steady) RPM reading, the spark transducer is good. If it does not give a stable reading, proceed as follows.

6. Carefully cut heat shrink tubing at location (A), and disconnect 8T5260 Fiber Optic Cable (5) from 8T5257 Receiver Unit (6).

7. Look closely at the end of 8T5260 Fiber Optic Cable (5). A red light pulse should be present each time the coil fires. If the red light pulse is visible it is an indication that 8T5257 Receiver Unit (6) needs to be replaced. If the red light IS NOT visible, proceed as follows.

8. Carefully cut heat shrink tubing at location (B), and disconnect 8T5260 Fiber Optic Cable (5) from 8T5259 Transmitter (7).

9. Check to see if there is a red light pulse at transmitter (7) where fiber optic cable (5) was disconnected. If a red light pulse is visible, it is an indication that 8T5260 Fiber Optic Cable (5) must be replaced. If there is no red light pulse, 8T5259 Transmitter (7) needs to be replaced.

Check of 6V9060 Spark Timing Adapter Group - (Using Function Generator and Frequency Counter)

1. Use 8T5258 Coil Adapter Cable (1) with cables shown to connect DMM (2), 8T5250 Engine Timing Indicator (3), frequency counter (4) and function generator (5) as shown.

2. Output of function generator (5) should be a 0-12 Volt, square wave, and the frequency should be set to 60 Hz. Use frequency counter (4) to check this frequency. Multimeter (2) can be used to set the output level of the signal generator.

NOTE: Make sure 8T5250 Engine Timing Indicator (3) is good, and that it operates correctly. If unsure, connect the engine timing indicator to an injection transducer from the 8T5301 Diesel Timing Adapter Group, and check timing indicator operation on a diesel engine. (The TDC Transducer does not need to be connected.)

3. With function generator (5) set for a positive square wave at 50% duty cycle, adjust the output level so multimeter (2) indicates 6.00 ± .05 Volts on the 20 Volt range.

4. With all components shown above turned ON, 8T5250 Engine Timing Indicator (3) should indicate a speed in the range of 3600 rpm. This is an indication that all components are operating correctly. If timing indicator (3) shows a speed range of 0, use the procedure beginning with Step 5 in the topic entitled Check of 6V9060 Spark Timing Adapter Group - (Using Spark Ignited Engine), in this instruction.

Replacement of 8T1005 Display Unit

If one or more segments do not show the correct reading on the 8T1005 Display Unit for RPM at location (A), or for DEG at location (B), the problem is most likely with the display unit at either location. Be sure to check for a good connection for each display unit. Use the procedure that follows should it be necessary to remove a display unit.

1. Remove the six screws (1) from front panel (2). Remove panel (2) from case (3).

2. Remove the four screws (4) from the PC board, and also remove the locknuts from the two front panel switches (5) and (6).

3. Carefully lift front panel (2) from PC (printed circuit) board (7).

4. To remove either display unit, (A) or (B), remove four screws (8) and carefully remove the unit from its position in the PC board.

Replacement of 6V4179 Digital Voltmeter Integrated Circuit

If one or more segments of either 8T1005 Display Unit, [RPM at location (A) or DEG at location (B)] do not work, refer to the topic entitled Replacement of 8T1005 Display Unit, in this instruction. After a display unit has been checked and/or a replacement installed and there is still a problem, or, if one display unit is completely blank while the other one works normally, the problem can be with a 6V4179 Digital Voltmeter (DVM) Integrated Circuit.

NOTE: There are two 6V4179 DVM Integrated Circuits in each 8T5250 Engine Timing Indicator.

1. Remove six screws (1), then remove panel (2) from case (3).

2. Use the hook end of 5P1720 Seal Pick (4) and carefully remove DVM integrated circuit, (5) or (6), as shown. [Use the notch at end (C) of the DVM as a reference mark to be used at time of installation.]

NOTE: At installation of a DVM, put the reference mark as given in Step 2, in the correct location. Also, be sure that the pins on the DVM are in alignment with the holes in the socket.

Parts and Repair Service Information

When one of the parts used with the timing indicator group is to be returned for a repair or warranty service, always give the following information:

* Description of the problem.

* Where to send part after repair (shipping address).

* Serial number (if applicable).

* Name of the person designated to receive the part after it is repaired.

* Billing address if different than shipping address.

8T5300 Engine Timing Indicator Group

Units less than one year old will be repaired under warranty (except for abuse). The cost of out-of-warranty repairs will be charged to the owner.

Contact Caterpillar Service Technology Group for details.

Use the following list to direct troubleshooting questions and/or information on service and warranty.

Telephone-Toll Free Numbers

Outside Illinois 1-800-542-8665

Inside Illinois 1-800-541-8665

Canada 1-800-523-8665

Outside of North America use Telex Number 404435

U.S.Mail

Caterpillar Inc.

Attn: Caterpillar Service Technology Group

600 W. Washington St., LD180

East Peoria, IL 61602

United Parcel Service, Emery, etc.

Caterpillar Inc.

Attn: Caterpillar Service Technology Group

330 S.W. Adams St. LD180

Peoria IL 61602

TDC Magnetic Transducer

The TDC Magnetic Transducer can not be repaired. For warranty purposes only, send the transducer to:

Electro Corporation

1845 57th Street

Sarasota, FL 33580 U.S.A.

6V7910 Injection Transducer

The 6V7910 Injection Transducer can not be repaired, but it can be returned for warranty.

NOTE: Before returning the transducer, write to or call, Viatran Corp. for a return authorization number. Do not send the transducer without the return authorization number.

After receipt of the return authorization number, send the transducer to the address that follows:

Viatran Corp.

300 Industrial Drive

Grand Island, N.Y. 14072 U.S.A.

Telephone: (716) 773-1700

If it is suspected that the RPM and DEG readings of the 8T5250 Engine Timing Indicator are unstable, use the information that follows to check 6V7910 Injection Transducer operation.

An unstable reading of 000 at the RPM display of the indicator [(6V0050 in 6V3100) or (8T5250 in 8T5300)], DEG readings at Low Idle speed, and valid RPM readings but unstable DEG readings at High Idle speed are most likely caused by air that is trapped in the transducer cavity, or in the tubing.

Although readings are obtained at High Idle speed, they may not be accurate because the trapped air, acting as a shock absorber, will delay the pressure pulse.

The solution to this problem is to purge this air that is either trapped in the injection transducer cavity, or in the tubing.

There are two methods of solving this problem. The first method is to purge the air from the injection transducer cavity by running the engine at maximum governor speed until the RPM and DEG readings are steady.

The second method is to purge the air from the transducer cavity by filling the cavity with diesel fuel, silicone or glycerin. To do this, use the procedure that follows.

1. Obtain a plastic squeeze bottle that has a minimum capacity of 90 mL (3 oz). Remove the cap from the snout on the lid.

2. Use a number 58 (.0420") drill bit to enlarge the hole in the snout of the plastic lid.

3. Obtain some plastic tubing (teflon, nylon, polyethylene or equivalent) with an approximate inside diameter of 0.558 mm (0.022"), and a wall thickness of 0.254 mm (0.010"). Cut the tubing to a length of 88.9 to 127.0 mm (3.50 to 5.00").

4. Insert the tubing into the enlarged hole in the snout of the squeeze bottle cap. Pull the tubing partially through the cap.

5. Use a fine point soldering iron, or a similar tool, to flare the end of the tubing that is inside of the cap. Cool the flared end immediately so it does not shrink and return to its original shape.

After the flared end of the tubing has cooled, pull the tubing out so the flared end comes into contact with the inside part of the cap.

6. Immerse the plastic squeeze bottle in the fluid that is to be used (diesel fuel, silicone or glycerin) and fill the bottle with the fluid. Put the cap (with installed tubing) on the bottle and tighten the cap.

7. Hold 6V7910 Injection Transducer (1) in an upright position. Install the 5P7435 Adapter onto the injection transducer. Insert the end of the plastic tubing through the adapter, into the transducer until the end of the tube bumps into the diaphragm of the injection transducer.

Squeeze the plastic bottle to force the fluid into the transducer cavity until fluid begins to exit at the point where the plastic tube enters the 5P7435 Adapter.

While maintaining pressure on the squeeze bottle, slowly withdraw the end of the plastic tube from the transducer adapter. This will insure that the fluid fills the cavity that was previously occupied by the plastic tube and air.

8. Keep the tube end of the injection transducer in an upright position until it is installed on the engine. After the injection transducer is installed and all connections have been completed, start the engine and run it at full throttle for 8 - 12 minutes. This will permit all components to reach normal operating temperature and allow any remaining air to be purged from the transducer cavity.

DYNAMIC TIMING CHART