Adjustment of the Compression Brake
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To prevent possible injury, do not use the starter to turn the flywheel. Hot engine components can cause burns. Allow additional time for the engine to cool before measuring valve clearance. |
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This engine uses high voltage to control the fuel injectors. Disconnect electronic fuel injector enable circuit connector to prevent personal injury. Do not come in contact with the fuel injector terminals while the engine is running. |
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Note: The engine valve lash must be adjusted before adjusting the slave piston lash.
Reference: Testing and Adjusting, "Air Inlet and Exhaust System"
| Slave Piston Lash Setting Jake Brake Compression Brakes |
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|---|---|
| Serial Number Prefix | Slave Piston Lash Setting |
| 3CS1-UP 2PN1-UP 8YS1-UP |
0.64 ± 0.08 mm (0.025 ± 0.003 inch) |
| CPD1-UP 9SM1-UP 2KS1-UP 9NS1-UP |
1.02 ± 0.08 mm (0.040 ± 0.003 inch) |
| 1YN1-UP | 1.14 ± 0.08 mm (0.045 ± 0.003 inch) |
| MBJ1-UP MBL1-UP |
1.40 ± 0.08 mm (0.055 ± 0.003 inch) |
Note: Slave piston lash is measured between the slave piston and the actuating pin that is on the exhaust valve bridge. Adjustments to the slave piston must be completed while the engine is stopped and the exhaust valves are closed.
Use the following procedure to adjust the slave piston lash on cylinders 1, 3, and 5:
- Put No. 1 piston at the top center position on the compression stroke.
- Loosen adjustment locknut (1) .
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| Illustration 1 | g00481680 |
Compression brake (1) Adjustment screw and locknut (2) Slave piston (3) Actuating pin | |
- Place the appropriate feeler gauge between slave piston (2) and screw assembly (3). Turn the adjustment screw in a clockwise direction. Slide the feeler gauge between the slave piston and the screw assembly. Continue turning the adjustment screw until a slight drag is felt on the feeler gauge. Remove the feeler gauge.
- Tighten adjustment locknut (1) to a torque of 35 N·m (25 lb ft). Recheck the slave piston lash after tightening the locknut.
- Continue to check the slave piston lash for each of the cylinders that have been designated for adjustment. After each adjustment, tighten the locknut for the valve adjustment screw to a torque of 35 N·m (25 lb ft) and recheck the slave piston lash adjustment.
- Remove the timing bolt and turn the flywheel by 360 degrees in the direction of engine rotation. This will put No. 6 piston at the top center position on the compression stroke. Install the timing bolt in the flywheel.
Reference: Testing and Adjusting, "Finding the Top Center Position For No. 1 Piston"
Follow steps 2 through 5 in order to adjust the slave piston lash on cylinders 2, 4, and 6.
- Remove the timing bolt from the flywheel after all adjustments have been made. Reinstall the timing cover on the flywheel housing.
Reference: Refer to Troubleshooting, "Retarder Solenoid Circuits Test" for information that is related to testing the compression brake circuit.
Reference: Refer to Testing and Adjusting, "Fuel System" for information that is related to the adjustment of the electronic unit injector.