C11 and C13 Engines for Caterpillar Built Machines Variable Valve Actuators - Inspect/Adjust Caterpillar

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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.

Note: Lash for the Variable Valve Actuator (VVA) is measured between the rocker arm and the actuator piston. All measurements and adjustments must be made to a cold engine with the valves closed.

Checking the Variable Valve Actuator Lash

An adjustment is not necessary if the measured lash is in the acceptable range in Table 1. All engines may not have actuator pistons for both the inlet rocker arm and the exhaust rocker arm. Check and adjust your lash setting accordingly.

Illustration 1	g00948824
Intake rocker arm and actuator piston

If the measurement is not within this range, an adjustment is necessary. Refer to "Adjusting the Variable Valve Actuator Lash" for the proper procedure.

Adjusting the Variable Valve Actuator Lash

Note: The valve lash must be set prior to setting the lash for the variable valve actuator.

Use the following procedure to adjust the lash for the variable valve actuator:

1. Put the No. 1 piston at the top center position on the compression stroke. Refer to Testing and Adjusting, "Finding Top Center Position for No. 1 Piston". The valve lash must be set before the lash of the variable valve actuator can be adjusted. Also, the valve cover base must be torqued before the lash of the variable valve actuator can be adjusted.
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   Table 2

   TC Compression Stroke	Inlet Rocker Arm
   Variable Valve Actuator Lash	0.610 ± 0.075 mm (0.0240 ± 0.0030 inch)
   Cylinders	1-2-4

2. Adjust lash for the variable valve actuator according to Table 2.

   1. Loosen the jam nut.

   2. Place the appropriate feeler gauge between the actuator piston and the rocker arm. Then, turn the adjustment screw in a clockwise direction. Slide the feeler gauge between the actuator piston and the rocker arm. Continue turning the adjustment screw until the piston of the variable valve Actuator prevents the feeler gauge from being removed. There should be a tight hold on the feeler gauge. Turn the adjustment screw counterclockwise in order to loosen the feeler gauge. Refer to Table 2 for the correct variable valve actuator lash. Remove the feeler gauge.

   3. Tighten the jam nut to a torque of 50 ± 10 N·m (37 ± 7 lb ft). Do not allow the adjustment screw to turn while you are tightening the jam nut. Recheck the lash setting after tightening the jam nut.

3. Remove the timing bolt and turn the flywheel by 360 degrees in the direction of engine rotation. This will put the No. 6 piston at the top center position on the compression stroke. Install the timing bolt in the flywheel.
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   Table 3

   TC Exhaust Stroke	Inlet Rocker Arm
   Variable Valve Actuator Lash	0.610 ± 0.075 mm (0.0240 ± 0.0030 inch)
   Cylinders	3-5-6

4. Adjust lash for the variable valve actuator according to Table 3.

   1. Loosen the jam nut.

   2. Place the appropriate feeler gauge between the actuator piston and the rocker arm. Then, turn the adjustment screw in a clockwise direction. Slide the feeler gauge between the actuator piston and the rocker arm. Continue turning the adjustment screw until the piston of variable valve actuator prevents the feeler gauge from being removed. There should be a tight hold on the feeler gauge. Turn the adjustment screw counterclockwise in order to loosen the feeler gauge. Refer to Table 3 for the correct variable valve actuator lash setting. Remove the feeler gauge.

   3. Tighten the jam nut to a torque of 50 ± 10 N·m (37 ± 7 lb ft). Do not allow the adjustment screw to turn while you are tightening the jam nut. Recheck the lash setting after tightening the jam nut.

5. Remove the timing bolt from the flywheel after all adjustments have been made. Reinstall the timing cover.

Note: The valve lash must be adjusted before adjusting the compression brake, if equipped.

Refer to Testing and Adjusting, "Electronic Unit Injector - Adjust".