Rocker Arm Assembly: Service and Repair

ROCKER ARM AND PUSHROD REPLACEMENT

Fig. 6 Adjusting Valve Lash:

REMOVE OR DISCONNECT
1. Rocker arm cover.
2. Rocker arm nut.
^ If only the pushrod is to be replaced,back the rocker arm nut off until the rocker arm can be swung away from the pushrod. Then pull the pushrod out.
3. Rocker arm with ball.
4. Pushrod.

IMPORTANT:
^ Store used components in order so they can be reassembled in the same location.

INSPECT
^ Rocker arms and balls at their mating surfaces. These surfaces should be smooth and free from scoring or other damage.
^ Rocker arm areas which contact the valve stems and the sockets which contact the pushrods. These areas should be smooth and free of damage and wear.
^ Pushrods for bending. Roll the pushrod on a flat surface to determine if it is bent. Replace if necessary.
^ Ends of the pushrods for scoring or roughness.

INSTALL OR CONNECT
1. Pushrod. Make sure the pushrod seats properly in the hydraulic lifter.
2. Rocker arm with ball.

IMPORTANT
^ When new rocker arms and/or balls are installed, coat their bearing surfaces with "Molykote" or equivalent.

3. Rocker arm nut.

ADJUST
^ Valves as outlined later.

4. Rocker arm cover.

VALVE ADJUSTMENT
1. Remove the rocker arm cover.
2. Crank the engine until the mark on the vibration damper lines up with the "0,, mark on the timing tab and the engine is in the number one firing position. This may be determined by placing fingers on the number one valve as the mark on the damper comes near the "0" mark on the timing tab. If the rocker arms are not moving, the engine is in the number one firing position. If the rocker arms move as the mark comes up to the timing tab, the engine is in the number six firing position and should be turned over one more time to reach the number one position.
3. With the engine in the number one firing position as determined above, the following valves may be adjusted:

^ Exhaust: 1, 3, 4, 8.

^ Intake: 1,2, 5, 7.

(Even numbered cylinders are in the right bank; odd numbered cylinders are in the left bank, when viewed from the rear of the engine.)

4. Back out the adjusting nut until lash is felt at the pushrod then turn in the adjusting nut until all lash is removed. This can be determined by rotating the pushrod while turning the adjusting nut. When the play has been removed, turn the adjusting nut in three quarters (3/4) additional turn (to center the lifter plunger).
5. Crank the engine one revolution until the timing tab "0" mark and vibration damper mark are again in alignment. This is the number six firing position; the following valves may be adjusted:

^ Exhaust: 2, 5, 6, 7.

^ Intake: 3, 4, 6, 8.

6. Install the rocker arm cover.