C-10 Petroleum Engine Caterpillar

Engine Valve Lash - Inspect/Adjust

Usage:

C-10 Z2B

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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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The connection of any electrical equipment and the disconnection of any electrical equipment may cause an explosion hazard which may result in injury or death. Do not connect any electrical equipment or disconnect any electrical equipment in an explosive atmosphere.

Note: Valve lash is measured between the rocker arm and the valve bridge. All measurements and adjustments must be made with the engine stopped and the valves fully closed.

Valve Lash Check

An adjustment is NOT NECESSARY if the measurement of the valve lash is in the acceptable range in Table 1.

Prior to checking the valve lash, 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".

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Table 1
	Inlet Valves	Exhaust Valves
Valve Lash Check (Stopped Engine)	0.38 ± 0.08 mm (0.015 ± 0.003 inch)	0.64 ± 0.08 mm (0.025 ± 0.003 inch)
TC Compression Stroke	1-2-4	1-3-5
TC Exhaust Stroke ⁽¹⁾	3-5-6	2-4-6
Firing Order	1-5-3-6-2-4 ⁽²⁾

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^( 1 )	360° from TC compression stroke
^( 2 )	The No. 1 cylinder is at the front of the engine.

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

Valve Lash Adjustment

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Illustration 1	g01101255
Cylinder and valve location (A) Exhaust valves (B) Inlet valves

Use the following procedure to adjust the valve lash:

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".

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Table 2
TC Compression Stroke	Inlet Valves	Exhaust Valves
Valve Lash	0.38 ± 0.08 mm (0.015 ± 0.003 inch)	0.64 ± 0.08 mm (0.025 ± 0.003 inch)
Cylinders	1-2-4	1-3-5

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Illustration 2	g01104149
Adjustment of the valves (1) Inlet rocker arm (2) Adjustment locknut (3) Exhaust valve rocker arm (4) Adjustment locknut

Adjust the valve lash according to Table 2.
1. Lightly tap the rocker arm at the top of the adjustment screw with a soft mallet. This will ensure that the lifter roller seats against the camshaft's base circle.
1. Loosen the adjustment locknut.
1. Place the appropriate feeler gauge between rocker arm and the valve bridge. Then, turn the adjustment screw in a clockwise direction. Slide the feeler gauge between the rocker arm and the valve bridge. Continue turning the adjustment screw until a slight drag is felt on the feeler gauge. Remove the feeler gauge.
1. Tighten the adjustment locknut to a torque of 30 ± 7 N·m (22 ± 5 lb ft). Do not allow the adjustment screw to turn while you are tightening the adjustment locknut. Recheck the valve lash after tightening the adjustment locknut.

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 ⁽³⁾	Inlet Valves	Exhaust Valves
Valve Lash	0.38 ± 0.08 mm (0.015 ± 0.003 inch)	0.64 ± 0.08 mm (0.025 ± 0.003 inch)
Cylinders	3-5-6	2-4-6

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^( 3 )

Position for No. 1 cylinder

Adjust the valve lash according to Table 3.
1. Lightly tap the rocker arm at the top of the adjustment screw with a soft mallet. This will ensure that the lifter roller seats against the camshaft's base circle.
1. Loosen the adjustment locknut.
1. Place the appropriate feeler gauge between rocker arm and the valve bridge. Then, turn the adjustment screw in a clockwise direction. Slide the feeler gauge between the rocker arm and the valve bridge. Continue turning the adjustment screw until a slight drag is felt on the feeler gauge. Remove the feeler gauge.
1. Tighten the adjustment locknut to a torque of 30 ± 7 N·m (22 ± 5 lb ft). Do not allow the adjustment screw to turn while you are tightening the adjustment locknut. Recheck the valve lash after tightening the adjustment locknut.