GM Cadillac 1967-1989 Repair Guide

Rocker Arm Shaft Assembly

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All engines except the 6-252 and the 8-429 use rocker arms instead of rocker arm assemblies, please refer to Rocker Arm for procedures.

REMOVAL & INSTALLATION

6-252 and 8-429 Engines

See Figures 1, 2 and 3

  1. Remove the valve covers.
  2.  
  3. Remove the rocker arm shaft assembly bolts.
  4.  
  5. Remove the rocker arm shaft assembly and place it on a clean surface.
  6.  
  7. To remove the rocker arms from the shaft assembly use the procedure given below.
  8.  



Click image to see an enlarged view

Fig. Fig. 1: Exploded view of the rocker arm assembly - 8-429 engine



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Fig. Fig. 2: Replacement rocker arm identification - 6-252 engine



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Fig. Fig. 3: Removing the nylon retainer - 6-252 engine

DISASSEMBLY AND ASSEMBLY



6-252 Engine
  1. To remove the rocker arms from the shaft, you must first remove the nylon arm retainers. These can be removed with by prying them out with locking jaw pliers or breaking them by hitting them below the head with a chisel.
  2.  
  3. Remove the rocker arms from the shaft. Make sure you keep them in order. Also note that the external rib on each arm points away from the rocker arm shaft bolt located between each pair of rocker arms.
  4.  
  5. If you are installing new rocker arms, note that the replacement rocker arms are marked R and L for right and left side installation. Do not interchange them.
  6.  
  7. Install the rocker arms on the shaft and lubricate them with oil.
  8.  

Install the rocker arms for each cylinder only when the lifters are off the cam lobe and both valves are closed.

  1. Center each arm on the 1 / 4 in. (6mm) hole in the shaft. Install new nylon rocker arm retainers in the holes using a 1 / 2 in. drift.
  2.  
  3. Locate the push rods in the rocker arm cups and insert the shaft bolts. Tighten the bolts a little at a time to 30 ft. lbs. (41 Nm).
  4.  
  5. Install the valve covers using sealer or new gaskets.
  6.  

8-429 Engine
  1. Remove the cotter pin from the end of the rocker shaft (end with chamfered edge) and remove the washer, spring, and second washer. Discard the cotter pin.
  2.  
  3. Remove the rocker arms, brackets, and springs from the shaft, keeping them in order so that they can be installed in the exact same position.
  4.  
  5. Measure the rocker shaft in center of the rocker arm wear pattern. If this diameter is more than 0.003 in. (0.08mm) smaller than the diameter of the shaft in the adjacent, unworn section, the shaft should be replaced.
  6.  

To assemble:
  1. If a new rocker shaft is necessary, install a new cotter pin on end of shaft (end without chamfered edge).
  2.  
  3. Install the washer, spring washer, and second washer over the shaft.
  4.  
  5. Install the rocker arms, brackets, and springs on shaft as shown in the illustration.
  6.  

The oil grooves in the rocker shaft should face downward toward the cylinder head and the notches in ends of shaft should face the engine when the assembly is installed on cylinder head.

  1. Install the washer, spring washer, and second washer on the shaft and secure with a new cotter pin.
  2.  

The thinner end of the rocker shaft brackets should be against the heads of screws.

  1. Reinstall the rocker arm shaft on the cylinder head.
  2.  

 
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