Rocker Arm Assembly: Service and Repair

This article has been updated with TSB No. 47-61-41A

ROCKER ARM, PUSHROD, AND STUD






REMOVE OR DISCONNECT
1. Valve rocker arm covers.
2. Rocker arm nuts.
^ Keep components separated so they may be installed in the same location.
3. Rocker arm pivot ball(s).
4. Rocker arm(s).
5. Rocker arm stud(s).
6. Pushrods (intake and exhaust pushrods are different lengths with the exhaust pushrod being the longer of the two:
^ Intake valve push rods are painted with two yellow stripes and measure 144.18 mm (5.68 inches) long.
^ Exhaust valve push rods are painted with two green stripes and measure 152.51 mm (6.0 inches) long.

INSTALL OR CONNECT
1. Pushrods (install correct length pushrods).
^ Intake valve push rods are painted with two yellow stripes and measure 144.18 mm (5.68 inches) long.
^ Exhaust valve push rods are painted with two green stripes and measure 152.51 mm (6.0 inches) long.
^ Make sure pushrods seat in lifter.
2. Rocker arm stud(s).
3. Rocker arm(s).

IMPORTANT
^ Coat friction surfaces of rocker arms and pivot balls with camshaft and lifter prelube GM P/N 1052365 (or equivalent).

4. Rocker arm pivot ball(s).
5. Rocker arm nut(s).

WITH STANDARD NON-ADJUSTABLE ROCKER ARMS

TIGHTEN
^ Nuts to 24 Nm (18 lb. ft.).

WITH SERVICE ADJUSTABLE ROCKER ARMS

INSTALL OR CONNECT
1. Lower intake manifold gaskets (143).
2. Pushrods (129).
^ Install pushrods in their original location.
^ Coat the ends of the pushrods with prelube GM P/N 1052365.
^ Intake valve push rods are painted with two yellow stripes and measure 144.18 mm (5.68 inches) long.
^ Exhaust valve push rods are painted with two green stripes and measure 152.51 mm (6.0 inches) long.
3. Rocker arms (131) and balls (132).
^ Install rocker arms and balls in their original location.
^ Coat rocker arm balls and friction surfaces of rocker arms with prelube GM PIN 1052365.
4. Rocker arm nuts (133).

ADJUST
^ Valves when lifter is on base circle of camshaft lobe:
a. The engine should be in the #1 firing position. This may be determined by placing fingers on the #1 rocker arms as the engine assembly alignment mark on the front face of the torsional damper aligns with the arrow on the front cover. If the valves are not moving, the engine is in the # 1 firing position. If the valves move the engine is in # 4 firing position and should be rotated one revolution to reach the # 1 position.
b. With the engine in the # 1 position, the valves should be adjusted:

^ Exhaust - 1, 2, 3.

^ Intake - 1, 5, 6.

c. Tighten the adjusting nut until there is zero lash, this can be determined by rotating pushrod while turning adjusting nut. When lash has been removed, turn adjusting nut in 1-1/2 additional turns (to center lifter plunger).
d. Crank the engine one revolution. This is the # 4 firing position. With the engine in this position, the following valves should be adjusted to zero lash + 1-1/2 turns:

^ Exhaust - 4, 5, 6.

^ Intake - 2, 3, 4.


6. Valve rocker arm covers.

INSPECT
^ For valve train noise.