The timing dimension should be checked and reset, if necessary, to account for slipped accessory drive shaft coupling or worn timing gears. The timing dimension can be checked in either of the following manners.
Checking with 1P540 Flow Checking Tool Group and 3S2954 Timing Indicator Group
3S2954 Timing Indicator Group.9M9268 Dial Indicator.1P540 Flow Checking Tool Group.
Before performing flow check, locate (TC) compression position for No.1 piston.
Refer to Special Instruction (FM035709) for complete and detailed instructions for the fuel flow method of engine timing.
MEASURING PISTON TRAVEL
1. 3S3263 Adapter. 2. 9M9268 Dial Indicator. 3. 3S3264 Rod. 4. Precombustion chamber. 5. Inlet port. 6. Piston. 7. Crankshaft.
Travel of piston (6), from point of closing inlet port (5) to top center, can be found by using the 3S2954 Timing Indicator Group. Convert the travel of piston (6) into degrees to determine if engine timing is correct.
The 1P540 Flow Checking Tool Group is used to pressurize the fuel system. Maintain 10 to 15 psi (0.7 to 1.1 kg/cm2) fuel with the 1P539 Tank Assembly. This can be done with hand pump provided with the tank assembly or connecting shop air to the tank assembly.
Consult the chart to find the angle corresponding to the indicator reading. At the indicator reading and timing angle specified, fuel flow from the injection pump should be reduced to 6 to 12 drops per minute [point of closing inlet port (5)].
Checking with 8S4620 or 8S4618 Gauge
8S4618 Fuel Pump Lifter Gauge or8S4620 Fuel Pump Lifter Gauge,8S5417 Timing Fixture Plate, 8S4613 Wrench, 8S2244 Extractor
FUEL PUMP LIFTER GAUGE INSTALLED
1. 8S4620 Gauge for four cylinder engines and 8S4618 Gauge for six cylinder engines.
1. Locate (TC) compression position for No. 1 piston.
2. Remove No.1 fuel injection pump with 8S4613 Wrench and 8S2244 Extractor. Insert fuel pump lifter gauge (1) into the fuel pump bore (4).
3. With gauge seated in fuel pump housing, the higher step of the plunger (2) must be slightly above the top surface of the gauge body (3). The lower step of the plunger must be just below the top surface of the gauge body.
FUEL PUMP LIFTER GAUGE INSTALLED
1. Fuel pump lifter gauge. 2. Plunger. 3. Body. 4. Fuel pump bore.
NOTE: If plunger (2) of gauge (1) is in the position as stated in Step 3, rotate the crankshaft in the direction of normal rotation and observe the movement of plunger (2). Plunger (2) must rise. If plunger (2) does not rise, refer to ACCESSORY DRIVE SHAFT TIMING.
4. If the plunger in the gauge is not in the position stated in Step 3, check the accessory drive shaft timing. See the topic ACCESSORY DRIVE SHAFT TIMING.
5. If the accessory drive shaft timing is correct and the lifter gauge plunger was not in the position stated in Step 3, the pump timing dimension setting must be corrected. See FUEL INJECTION PUMP TIMING DIMENSION SETTING: OFF ENGINE.
Checking with 8S7167 Gauge
8S7167 Gauge,6F6922 Depth Micrometer, 4 to 5 in. (101.6 to 127.0 mm) rod,8S4613 Wrench, 8S2244 Extractor.
1. Locate (TC) compression position for No.1 piston.
2. Remove No.1 fuel injection pump with 8S4613 Wrench and 8S2244 Extractor. Insert gauge (2) into the housing fuel pump bore.
3. The correct timing dimension setting using depth micrometer (1) is:
Four cylinder: 4.2216 ± .0020 in. (107.229 ± 0.051 mm).
Six cylinder: 4.2179 ± .0020 in. (107.135 ± 0.051 mm).
CHECKING TIMING DIMENSION SETTING (Typical Example)
1. 6F6922 Depth Micrometer, 4 to 5 in. (101.6 to 127.0 mm) rod. 2. 8S7167 Gauge.
4. If the timing dimension setting measurement is not correct, check the accessory drive shaft timing. See ACCESSORY DRIVE SHAFT TIMING.
5. If the accessory drive shaft timing is correct and the timing dimension setting measurement was incorrect, the timing setting must be corrected. See FUEL INJECTION PUMP TIMING DIMENSION SETTING: OFF ENGINE.