GM Firebird 1967-1981 Repair Guide

Timing Gear Cover

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REMOVAL & INSTALLATION 230 and 250 Engines



See Figure 1

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Fig. Fig. 1: When installing the front cover on inline 6-cylinder engines, apply sealer on the positions shown


CAUTION
The EPA warns that prolonged contact with used engine oil may cause a number of skin disorders, including cancer! You should make every effort to minimize your exposure to used engine oil. Protective gloves should be worn when changing the oil. Wash your hands and any other exposed skin areas as soon as possible after exposure to used engine oil. Soap and water, or waterless hand cleaner should be used.

  1. Drain the oil and remove the oil pan on models through 1972.
  2.  


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. Remove the radiator after draining it.
  2.  
  3. Remove the fan, pulley, and belt. Remove any power steering and/or AIR pump drive belts. Remove any braces for the above pumps which will interfere with cover removal and position the pumps out of the way.
  4.  
  5. Remove the crankshaft pulley and damper. Use a puller to remove the damper. Do not attempt to pry or hammer the damper off, or it will be damaged.
  6.  
  7. Remove the retaining bolts, and remove the cover on 1968-72 models.
  8.  
  9. On 1973-76 models, pull the cover forward slightly and cut the oil pan front seal off flush with the block. Remove the cover. On installation, cut the tabs off a new oil pan front seal and install it on the cover.
  10.  
  11. On installation, coat the gasket with sealer and use a 1 / 8 in. bead of silicone sealer at the oil pan-to-cylinder block joint. Replace the damper before tightening the cover bolts down, so that the cover seal will align. The damper must be drawn into place. Hammering it will destroy it.
  12.  
  13. Install the oil pan if it was removed, and fill the crankcase with oil.
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265, 301, 305, 326, 350, 400, 403 and 455 Engines See Figures 2 through 12

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Fig. Fig. 2: When the front cover is removed on most 8-cylinder engines, the oil pan seal must be modified by cutting the tabs off



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Fig. Fig. 3: Apply sealer to the front pads of the oil pan on 8-cylinder engines during front cover installation



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Fig. Fig. 4: To remove the front cover, remove the crankshaft pulley bolts ...



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Fig. Fig. 5: ... then remove the pulley from the damper



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Fig. Fig. 6: Use a puller to loosen the damper, and, if the flywheel can't be held ...



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Fig. Fig. 7: ... use a prybar to keep the crankshaft from turning during removal



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Fig. Fig. 8: When loosened, remove the damper from the end of the crankshaft



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Fig. Fig. 9: Remove the front cover mounting bolts ...



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Fig. Fig. 10: ... carefully separate the cover from the engine block ...



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Fig. Fig. 11: ... and remove the cover



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Fig. Fig. 12: Make certain to retain the key for reinstallation


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. Drain the cooling system.
  2.  
  3. Loosen the alternator adjusting bolts.
  4.  
  5. Remove the fan, fan pulley and any accessory drive belts.
  6.  
  7. Disconnect the radiator hoses and remove the water pump.
  8.  
  9. Remove the fuel pump.
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  11. Remove the harmonic balancer bolt and washer.
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  13. Remove the harmonic balancer. Use a puller, do not attempt to pry or hammer the balancer off.
  14.  
  15. Remove the front four oil pan-to-front cover bolts, if equipped.
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  17. Unscrew and remove the front cover mounting bolts and nuts and the cover-to-intake manifold bolt.
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  19. Pull the front cover forward and remove it.
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  21. Remove the O-ring from the recess in the intake manifold and clean all the gasket surfaces.
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  23. Installation is in the reverse order of removal.
  24.  

231 Engine


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. Drain the cooling system. Remove the radiator hoses. Remove the radiator.
  2.  
  3. Remove all the drive belts. Remove the fan and fan pulley. Remove the bypass hose.
  4.  
  5. Remove the crank pulley, the fuel pump and the distributor. Note the position of the distributor rotor before you remove the distributor.
  6.  
  7. Remove the alternator and its bracket.
  8.  
  9. Remove the harmonic balancer. You'll need a puller.
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  11. Remove the two bolts which attach the oil pan to the front cover. Remove the bolts which attach the cover to the block.
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  13. Remove the cover and remove the gasket material.
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  15. To install, it is first necessary to remove the oil pump cover and pack the space around the oil pump gears completely full of petroleum jelly. Do not use gear lube. There must be no air space left inside the pump. Reinstall the pump cover using a new gasket. This step is very important since the oil pump may lose its prime any time it, the pump cover or the timing cover is disturbed. If the pump is not packed, it may not begin to pump oil as soon as the engine is started.
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  17. Install the cover, using a sealer and new gaskets. Make sure the dowel pins engage the dowel pin holes before starting the bolts. Apply sealer to the bolt threads.
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  19. Install the harmonic balancer, bolt and washer. It will be necessary to lock the flywheel in some way to tighten the balancer bolt to specifications. Most mechanics remove the flywheel cover and hold the flywheel stationary with a large prytool.
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  21. The rest of the installation is in the reverse order of removal.
  22.  

TIMING GEAR COVER OIL SEAL REPLACEMENT All Engines



See Figure 13

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Fig. Fig. 13: With the front cover removed, the new seal can be driven in while the cover is resting on a clean, flat surface

See Figure 14

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Fig. Fig. 14: A new oil seal can also be installed while the front cover is still installed on the engine

  1. After removing the gear cover, pry the oil seal out of the front of the cover with a large prytool.
  2.  
  3. Install a new lip seal with the lip (open side of seal) inside and drive or press the seal into place.
  4.  
  5. Lightly coat the seal with engine oil before replacing the cover on the block.
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