GM Firebird 1967-1981 Repair Guide

Rocker Arms

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REMOVAL & INSTALLATION Except 231 Engine



See Figures 1 through 8

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Fig. Fig. 1: Rocker arm, ball, nut and related spring components used on all engines, but the 231 V6 engine



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Fig. Fig. 2: To remove the rocker arms, first remove the cover hold-down bolts ...



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Fig. Fig. 3: ... then lift the cover off of the cylinder head



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Fig. Fig. 4: Loosen the rocker arm nut ...



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Fig. Fig. 5: ... then remove the nut and pivot ball



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Fig. Fig. 6: Lift the rocker arm off of the stud



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Fig. Fig. 7: At this time, the pushrods can be removed make sure to label them if more than one is removed



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Fig. Fig. 8: Before installing the rocker arms, inspect the pivot balls for wear except 231 and OHC engines

  1. Remove the valve covers.
  2.  
  3. Remove the rocker arm nut and rocker arm ball.
  4.  
  5. Lift the rocker arm on the rocker arm stud. Always keep the rocker arm assemblies in order and assemble them on the same stud.
  6.  
  7. Remove the pushrod from its bore. Make sure that the rods are returned to their original bores, with the same end in the block.
  8.  
  9. Reverse the removal procedure to install the rocker arms and adjust the valve on any rocker arm that was removed before installing the valve cover.
  10.  

231 Engine

  1. Remove the rocker arm covers.
  2.  
  3. Remove the rocker arm shaft assembly bolts.
  4.  
  5. Remove the rocker arm shaft assembly.
  6.  
  7. To remove the rocker arms from the shaft, the nylon arm retainers must be removed. They can be removed with a pair of water pump pliers, or they can be broken by hitting them below the head with a chisel.
  8.  
  9. 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.
  10.  
  11. If you are installing new rocker arms, note that replacement rocker arms are marked "R" and "L" for right and left side installation. Do not interchange them.
  12.  
  13. Install the rocker arms on the shaft and lubricate them with oil.
  14.  
  15. Center each arm on the 1 / 4 in. hole in the shaft. Install new nylon rocker arm retainers in the holes using a 1 / 2 in. drift.
  16.  
  17. Locate the pushrods in the rocker arms and insert the shaft bolts. Tighten the bolts a little at a time until they are tight.
  18.  
  19. Install the rocker covers using new gaskets.
  20.  

ROCKER ARM STUD REMOVAL & INSTALLATION 1967-74 Models



OHV 230 AND 250 ENGINES
  1. Remove the rocker cover and rocker arm.
  2.  
  3. File two slots, 3 / 32 - 1 / 8 in. deep, on opposite sides of the stud. The bottom of the slots should be 1 / 2 in. from the top of the stud hole.
  4.  
  5. Place a spacer washer (or tool No. J-6392-3) over the stud, then position a stud remover (or tool J-6329-1 on the stud and tighten it securely.
  6.  
  7. Place a spacer (a socket or tool No. J-6392-2) over the stud remover, then thread a 7 / 8 in. nut onto the stud remover and turn it in until the stud pulls free from the head.
  8.  
  9. If an oversize stud is to be used (0.003 and 0.013 in. oversize studs are available), ream the stud hole to size.
  10.  

To install:
  1. Coat the press fit area of the stud with axle lube, then press or hammer it into place.
  2.  

The factory recommends that tool No. J-6880 be used for this job. This tool is simply a sleeve that is held in place with an allen screw it protects the threads from damage. A similar homemade tool will work if care is exercised. Do not hammer directly on the stud, because it is hardened and will fracture if subjected to shock.

326, 350, 400 AND 455 ENGINES

This procedure can be used only on engines with pressed-in rocker studs. Special high-performance engines have screwed-in rocker studs which are easily identified by their hex head lower portion. Another common aftermarket, stud-securing procedure on standard engines is "pinning" pressed-in studs by drilling through the stud boss and stud and inserting an interference-fit roll pin. Make sure that any such pins are removed before attempting the following procedure.


CAUTION
When draining engine coolant, keep in mind that cats and dogs are attracted to ethylene glycol antifreeze and could drink any that is left in an uncovered container or in puddles on the ground. This will prove fatal in sufficient quantity. Always drain coolant into a sealable container. Coolant should be reused unless it is contaminated or is several years old.

  1. Disconnect the battery and drain the cooling system.
  2.  
  3. Remove the rocker cover.
  4.  
  5. Pack oily rags around the stud holes and engine openings, to catch any metal chips.
  6.  
  7. Remove the rocker arm and pushrod, then file two slots 3 / 32 - 1 / 8 in. deep on opposite sides of the stud. The top of the slots should be 1 / 4 - 3 / 8 in. below thread travel.
  8.  
  9. Place a spacer washer (or tool No. J-8934-3) over the stud, then position a stud remover (or tool No. J-8934-1) on the stud and tighten the allen screws.
  10.  
  11. Place a spacer (a socket or tool No. J-8934-2) over the remover, then thread a 7 / 8 in. nut on the stud remover and turn it in until the stud pulls out from the head.
  12.  
  13. If an oversize stud is to be used (0.003 in. oversize studs are available), ream the stud hole to the proper size, then clean any chips from the area.
  14.  

To install:
  1. Refer to Step 6 of the OHV 6-cylinder stud replacement procedure, substituting factory tool No. J-23342 for J-6880.
  2.  

Valve adjustment for Ram Air IV engines is covered in Engine Performance And Tune-up .

1975-81 Models

Most 1975 and later Firebirds are equipped with engines which use the screw-in rocker studs; the main exception being the 305 and 350 V8 engines which are produced by Chevrolet and use the pressed-in type. Screw-in rocker studs can be readily identified by their hex head lower portion.

  1. Remove the rocker cover.
  2.  
  3. Remove the rocker arm and nut.
  4.  
  5. Remove the stud, using a deep well socket.
  6.  
  7. Install the new stud and tighten it to 50 ft. lbs.
  8.  

 
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