Rocker Arm Assembly: Service and Repair

CAUTION: Place the valve rocker arms, the valve rocker arm balls, and the pushrods in a rack in order to ensure reinstallation to the original locations.





REMOVAL
1. Remove the valve rocker arm covers.
2. Remove the valve rocker arm nuts (1) and the valve rocker arm balls (2).
3. Remove the valve rocker arms (3) and studs (4).





4. Remove the valve rocker arm pushrods.

INSTALLATION

NOTE: Coat the bearing surfaces of the valve rocker arms and the valve rocker arm balls with pre lube, GM P/N 1052365 or the equivalent prior to installation. Install these components and the pushrods in the original locations, prior to removal. Coat the threads of the valve rocker arm studs with sealant GM P/N 12346004 or equivalent prior to installation.

1. Install the valve rocker arm pushrods. Ensure that the pushrods seat in the lifter sockets.
2. Install the valve rocker arm studs (4). Tighten the valve rocker arm studs to 68 Nm (50 ft. lbs.).
3. Install the valve rocker arms (3).
4. Install the valve rocker arm balls (2) and the valve rocker arm nuts (1). Tighten the valve rocker arm nuts until the lash is eliminated.
5. Turn the crankshaft until the cast arrow on the crankshaft balancer hub is in the 12 o'clock position and the number 1 cylinder is in the firing position (top dead center).
6. Watch the number 1 cylinder valves as the crankshaft balancer hub arrow approaches the 12 o'clock position. If a valve moves as the arrow moves to the position, the engine is in the number 6 cylinder firing position. Turn the crankshaft one more revolution to reach the number 1 cylinder firing position.
7. With the engine in the number 1 cylinder firing position, adjust the following valves:
^ Exhaust 1, 3, 4, 8
^ Intake 1, 2, 5, 7
8. Back off the valve rocker arm nut until the lash is felt in the pushrod.
9. Tighten the valve rocker arm nut until all of the lash is removed.
10. Zero lash can be felt by moving the pushrod up and down using the thumb and the forefinger until there is no more movement.
11. When all the free play has been removed, tighten the valve rocker arm nut one additional turn.
12. Turn the crankshaft one revolution until the hub arrow is again at 12 o'clock position. This is the number 6 cylinder firing position. Adjust the following valves:
^ Exhaust 2, 5, 6, 7
^ Intake 3, 4, 6, 8
13. Install the valve rocker arm covers.