GM Camaro/Firebird 1993-1998 Repair Guide

Camshaft, Lifters and Bearings

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REMOVAL & INSTALLATION



3.4L and 5.7L Engines

See Figures 1, 2, 3 and 4

  1. Take the vehicle to a reputable repair shop to have the A/C system properly discharged.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Remove the upper intake manifold assembly.
  6.  
  7. Remove the rocker arms and pushrod assemblies.
  8.  
  9. Remove the lower intake manifold assembly.
  10.  
  11. Unfasten the bolt/screw, clamp and oil pump drive assembly.
  12.  



Click image to see an enlarged view

Fig. Fig. 1: Unfasten the retaining bolt and clamp, then remove the oil pump drive

  1. Remove the timing chain (front) cover assembly.
  2.  
  3. Remove the camshaft sprocket.
  4.  
  5. Remove the valve lifters.
  6.  
  7. Disconnect the A/C compressor and condenser hose from the condenser.
  8.  
  9. Disconnect the A/C receiver and dehydrator hose from the condenser.
  10.  
  11. Remove the radiator with the condenser. Remove the A/C condenser support assembly.
  12.  

All camshaft journals are the same diameter so care must be used when removing the camshaft to avoid damaging the bearings.

  1. Remove the camshaft assembly, as follows:
    1. Install three 5/16-18 x 4-inch bolts in the camshaft bolt holes.
    2.  
    3. Carefully rotate and pull the camshaft assembly out of the bearings.
    4.  

  2.  



Click image to see an enlarged view

Fig. Fig. 2: Carefully pull the camshaft out, using the bolts threaded into the camshaft

  1. Inspect the bearings for scratches, pits or loose fit. If necessary, remove the camshaft bearings as follows:
    1. Select the proper expander assembly and driving washer.
    2.  
    3. Assemble tool J 33049 or equivalent camshaft bearing removal tool. Tighten the expander assembly snug with the camshaft bearing.
    4.  
    5. Drive out the bearings.
    6.  

  2.  



Click image to see an enlarged view

Fig. Fig. 3: Use the proper tool to remove the camshaft bearings

To install
  1. Install new camshaft bearings, as follows:
    1. Select front, rear and intermediate camshaft bearings.
    2.  
    3. Select the proper expander assembly and driving washer.
    4.  
    5. Assemble tool J 33049.
    6.  
    7. Place the intermediate camshaft bearing onto tool J 33049 and index the oil hole at 4 o'clock when looking from the front of the engine block. Drive the intermediate camshaft bearings into place.
    8.  
    9. Install the number 4 camshaft bearing with the oil hole indexed at 4 o'clock when looking from the front of the engine block, using J 33049.
    10.  
    11. Install the number 1 camshaft bearing with the oil hole indexed at 4 and 7 o'clock when looking from the front of the engine block using tool J 33049.
    12.  

  2.  
  3. With a piece of 3/32 in. brass rod with a 90 degree bend at the end, probe the bearing oil holes and make sure they are properly aligned.
  4.  



Click image to see an enlarged view

Fig. Fig. 4: Check the camshaft bearing oil hole alignment

  1. When installing a new camshaft assembly, coat the camshaft lobes with "Molykote" or equivalent. When installing a new camshaft, replace all valve lifters to ensure durability of the camshaft lobes and lifter rollers.
  2.  
  3. Lubricate all camshaft journals with engine oil, then install the camshaft assembly.
  4.  
  5. Install the A/C condenser support assembly.
  6.  
  7. Install the radiator with the A/C condenser.
  8.  
  9. Connect the A/C receiver and dehydrator hose to the condenser. Attach the A/C compressor and condenser hose to the condenser.
  10.  
  11. Install the valve lifters.
  12.  
  13. Install the camshaft sprocket.
  14.  
  15. Install the timing chain (front) cover.
  16.  
  17. Lubricate the oil pump drive gear with prelube 1052365 and coat the assembly with engine oil, then install the oil pump drive assembly, clamp and bolt/screw. Tighten the bolt to 25 ft. lbs. (34 Nm).
  18.  
  19. Install the lower intake manifold.
  20.  
  21. Install the pushrods and rocker arms.
  22.  
  23. Install the upper intake manifold.
  24.  
  25. Connect the negative battery cable.
  26.  
  27. Take the vehicle to a reputable repair shop to have the A/C system charged.
  28.  

3.8L Engine

See Figure 5

  1. Take the vehicle to a reputable repair shop to have the A/C system properly discharged.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Remove the radiator with the A/C condenser assembly.
  6.  
  7. Remove the valve lifters.
  8.  
  9. Remove the timing chain (engine) front cover.
  10.  
  11. Remove the camshaft sprocket and timing chain.
  12.  
  13. Remove the camshaft thrust plate bolts/screws then remove the thrust plate.
  14.  
  15. Remove the camshaft assembly, as follows:
    1. Install three 5/16-18 x 4-inch bolts in the camshaft bolt holes.
    2.  
    3. Carefully rotate and pull the camshaft assembly out of the bearings.
    4.  

  16.  
  17. Inspect the camshaft for damage and replace if necessary.
  18.  
  19. Inspect the bearings for scratches, pits or loose fit. If necessary, remove the camshaft bearings as follows:
    1. Remove the rear main seal housing.
    2.  
    3. Assemble tool J 33049 or equivalent camshaft bearing removal tool as outlined by the manufacturer.
    4.  
    5. Drive out the bearings.
    6.  

  20.  



Click image to see an enlarged view

Fig. Fig. 5: Exploded view of the camshaft and bearings - 3.8L engine

To install:
  1. Install new camshaft bearings, as follows:
    1. Select front, rear and intermediate camshaft bearings.
    2.  
    3. Assemble tool J 33049 as outlined by the manufacturer.
    4.  
    5. Place the bearing on the tool.
    6.  
    7. Index the bearing oil holes with the cylinder block oil passages.
    8.  
    9. Install the rear main seal housing.
    10.  

  2.  
  3. Coat the camshaft with prelube 12345501 or equivalent, then install the camshaft.
  4.  
  5. Install the thrust plate and secure with the retaining bolts. Tighten to 11 ft. lbs. (15 Nm).
  6.  
  7. Install the timing chain (front) cover.
  8.  
  9. Install the valve lifters.
  10.  
  11. Install the radiator with the A/C condenser.
  12.  
  13. Connect the negative battery cable.
  14.  
  15. Take the vehicle to a reputable repair shop to have the A/C system charged.
  16.  

INSPECTION



Camshaft Lobe Lift

See Figure 6

Check the lift of each lobe in consecutive order and make a note of the reading.

  1. Remove the fresh air inlet tube and the air cleaner. Remove the heater hose and crankcase ventilation hoses. Remove valve rocker arm cover(s).
  2.  
  3. Remove the rocker arm stud nut or fulcrum bolts, fulcrum seat and rocker arm.
  4.  
  5. Make sure the pushrod is in the valve tappet socket. Install a dial indicator so that the actuating point of the indicator is in the pushrod socket (or the indicator ball socket adapter tool is on the end of the pushrod) and in the same plane as the pushrod movement.
  6.  
  7. Disable the ignition and fuel systems.
  8.  
  9. Install a remote starter switch. Crank the engine with the ignition and fuel system disabled. Turn the crankshaft over until the tappet is on the base circle of the camshaft lobe. At this position, the pushrod will be in its lowest position.
  10.  
  11. Zero the dial indicator. Continue to rotate the crankshaft slowly until the pushrod is in the fully raised position.
  12.  



Click image to see an enlarged view

Fig. Fig. 6: Measuring camshaft lobe lift

  1. Compare the total lift recorded on the dial indicator with the specification shown on the Camshaft Specification chart.
  2.  

To check the accuracy of the original indicator reading, continue to rotate the crankshaft until the indicator reads zero. If the lift on any lobe is below specified wear limits listed, the camshaft and the valve tappet operating on the worn lobe(s) must be replaced.

  1. Install the rocker arm, fulcrum seat and stud nut or fulcrum bolts. Adjust the valves, if required (refer to the valves procedure in this section).
  2.  
  3. Install the valve rocker arm cover(s) and the air cleaner.
  4.  

Camshaft End Play

On all gasoline V8 engines, prying against the aluminum-nylon camshaft sprocket, with the valve train load on the camshaft, can break or damage the sprocket. Therefore, the rocker arm adjusting nuts must be backed off, or the rocker arm and shaft assembly must be loosened sufficiently to free the camshaft. After checking the camshaft end play, check the valve clearance. Adjust the valves, if required (refer to thevalves procedurein this section).

  1. Push the camshaft toward the rear of the engine. Install a dial indicator or equivalent so that the indicator point is on the camshaft sprocket attaching screw.
  2.  
  3. Zero the dial indicator. Position a prybar between the camshaft gear and the block. Pull the camshaft forward and release it. Compare the dial indicator reading with the specifications.
  4.  
  5. If the end play is excessive, check the spacer for correct installation before it is removed. If the spacer is correctly installed, replace the thrust plate.
  6.  
  7. Remove the dial indicator.
  8.  

 
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