Rocker Arms
This article has been updated with TSB No. 47-61-41A
This article has been updated with TSB No. 57-61-35
Figure 1 - roller rocker arm:
Figure 2 - conventional ball and pivot rocker arm:
Approximately 4000 1995 A/N cars were built with roller rocker arms. All other 1995 3100 V6 engines were built with the conventional ball and pivot type rocker arm. For 1996 the 3100 V6 engine can be manufactured with either roller rocker arms or ball and pivot type rocker arms. Figure 1 shows a roller rocker arm as compared to Figure 2 which shows a conventional ball and pivot rocker arm. You should not mix rocker arm types on the same engine. It will be necessary to determine which type of rocker arm design the engine was manufactured with when servicing the cylinder head valve train components.
VALVE ROCKER ARM AND PUSHROD
REMOVE OR DISCONNECT
1. Rocker ann nuts (133).
^ Place valve train parts in a rack so that they can be installed in the same location which they were removed.
2. Rocker arms (131) and balls (130).
3. Pushrods (129).
IMPORTANT
^ Use care when removing pushrods so they do not fall down into the lifter valley.
INSPECT
^ Rocker arms (131) and balls (132) for wear at rotation surfaces.
^ Pushrod (129) ends for wear.
^ Pushrod (129) for bends.
WITH STANDARD NON-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).
TIGHTEN
^ Nuts (133) 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.