GM Firebird 1982-1992 Repair Guide

Cylinder Head

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REMOVAL & INSTALLATION




CAUTION
Properly relieve the fuel system pressure before disconnecting any lines.

When servicing the engine, be absolutely sure to mark vacuum hoses and wiring so that these items may be properly reconnected during installation. Also, when disconnecting fittings of metal lines (fuel, power brake vacuum), always use two flare nut (or line) wrenches. Hold the wrench on the large fitting with pressure on the wrench as if you were tightening the fitting (clockwise), THEN loosen and disconnect the smaller fitting from the larger fitting. If this is not done, damage to the line will result.


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

2.5L Engine

See Figure 1



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Fig. Fig. 1: Cylinder head bolt torque sequence for 2.5L engine

  1. Disconnect the negative battery cable.
  2.  
  3. Drain the engine block and radiator of coolant.
  4.  
  5. Raise and safely support the vehicle. Remove the exhaust pipe and lower the vehicle.
  6.  
  7. Remove the oil level indicator tube.
  8.  
  9. Remove the air cleaner.
  10.  
  11. Unplug the electrical and vacuum connections and disconnect the linkage from the TBI unit.
  12.  
  13. Disconnect the fuel lines.
  14.  
  15. Remove the EGR valve.
  16.  
  17. Disconnect the heater hoses from the intake manifold.
  18.  
  19. Remove the ignition coil.
  20.  
  21. Disconnect all electrical connections from the intake manifold and cylinder head.
  22.  
  23. If the vehicle has air conditioning, remove the compressor and position it out of the way. Do not disconnect the refrigerant lines.
  24.  
  25. Remove the alternator and lay the unit aside. If necessary, remove the alternator brackets.
  26.  
  27. Remove any other brackets or components mounted on the cylinder head.
  28.  
  29. Remove the upper radiator hose.
  30.  
  31. Remove the rocker arm cover and back off the rocker arm nuts/bolts and pivot the rocker arms out of the way so that the pushrods can be removed. Identify the pushrods so that they can be reinstalled in their original locations.
  32.  
  33. Remove the cylinder head bolts and cylinder head. Remove the intake and exhaust manifolds, as required.
  34.  

To install:
  1. Thoroughly clean all mating surfaces of oil, grease and old gasket material. Clean the head bolts and cylinder block threads, otherwise an accurate torque specification will not be attained.
  2.  
  3. Install a new gasket on the block mating surface. Position the cylinder head on the block.
  4.  

Clean the bolt threads, apply sealing compound and install the bolts finger-tight.

  1. Tighten the head bolts a little at a time using the correct sequence and torque to 92 ft lbs. (125 Nm).
  2.  
  3. Install the pushrods and rocker arms. Refer to the procedures described earlier in this section.
  4.  
  5. Refill the cooling system and check for leaks. The remaining installation is the reverse of the removal procedure.
  6.  

2.8L and 3.1L Engines

See Figure 2



Click image to see an enlarged view

Fig. Fig. 2: Cylinder head bolt torque sequence for all V6 engines, except the 3.8L Turbo

  1. Disconnect the negative battery cable.
  2.  
  3. Relieve the fuel system pressure and drain the engine coolant from the radiator into a suitable container.
  4.  
  5. Remove the intake manifold and the spark plugs.
  6.  
  7. Remove the dipstick tube and bracket. Raise and support the vehicle safely. Drain the oil and remove the oil filter. Lower the vehicle.
  8.  
  9. Remove the exhaust manifolds.
  10.  
  11. Remove the drive belt(s).
  12.  
  13. Remove the air conditioning compressor and bracket, reposition it aside. Do not disconnect the lines.
  14.  
  15. Remove the power steering pump and bracket, reposition it aside.
  16.  
  17. Remove the alternator and bracket, reposition it aside.
  18.  
  19. Remove the ground cable from the rear of the cylinder head and remove the engine lift bracket.
  20.  
  21. Remove the rocker arm covers.
  22.  
  23. Loosen the rocker arms until the pushrods can be removed.
  24.  
  25. Remove the cylinder head bolts and remove the cylinder heads.
  26.  

To install:
  1. Clean the gasket mating surfaces of all components. Be careful not to nick or scratch any surfaces as this will allow leak paths. Clean the bolt threads in the cylinder block and on the head bolts. Dirt will affect bolt torque.
  2.  
  3. Place the head gaskets in position over the dowel pins.
  4.  
  5. Install the cylinder heads.
  6.  
  7. Coat the cylinder head bolts threads with GM sealer 1052080 or equivalent, and install the bolts. Tighten the bolts in the proper sequence to:

    1982-1987 engines: 70 ft lbs. (90 Nm)
     
    1988-1992 engines: 1st step: 40 ft lbs. (55 Nm); 2nd step: tighten an additional 1 / 4 (90 degree) turn
     

  8.  
  9. Install the pushrods and loosely retain them with the rocker arms. Make sure the lower ends of the pushrods are in the lifter seats. Refer to the rocker arm procedures outlined earlier in this section.
  10.  
  11. Install the power steering pump bracket and pump. Do the same for the air conditioning compressor bracket and compressor.
  12.  
  13. Install the ground cable to the rear of the cylinder head.
  14.  
  15. Install the exhaust manifolds.
  16.  
  17. Install the dipstick tube and bracket.
  18.  
  19. Install the intake manifold.
  20.  
  21. Install the alternator bracket and alternator.
  22.  
  23. Install the drive belt(s).
  24.  
  25. Install the spark plugs.
  26.  
  27. Fill the cooling system with the proper type and quantity of coolant. Install a new oil filter and fill the crankcase with the proper type and quantity of oil.
  28.  
  29. Connect the negative battery cable, start the vehicle and check for leaks.
  30.  

3.8L Turbo

See Figure 3

  1. Disconnect the negative (-) battery cable and drain the cooling system.
  2.  


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

  1. Remove the drive belt.
  2.  
  3. Left cylinder head: remove the air conditioning compressor and hang to the side with a piece of wire. Do NOT disconnect the refrigerant lines. Remove the alternator and mounting brackets and lay aside. Do the same for the power steering pump.
  4.  
  5. Right cylinder head: remove the turbocharger.
  6.  
  7. Remove the intake manifold and rocker arm covers as outlined in this section.
  8.  
  9. Remove the cylinder head bolts and cylinder head. Tap the side of the head with a plastic hammer to dislodge the gasket. Do NOT try to pry off with a screwdriver between the mating surfaces.
  10.  

To install:
  1. Before installing, clean the gasket surfaces of the head and block with solvent and a gasket scraper.
  2.  
  3. Check the cylinder head for warpage using a straight edge.
  4.  
  5. Make sure the retaining bolt threads and the cylinder block threads are clean since dirt could affect bolt torque.
  6.  
  7. Match up the old head gasket with the new one to ensure the holes are EXACT. Install a new gasket over the dowel pins in the cylinder block.
  8.  
  9. Install the cylinder head in place over the dowel pins.
  10.  
  11. Coat the cylinder head bolt threads with sealing compound and install finger-tight.
  12.  
  13. Torque the cylinder head bolts gradually using the correct sequence.
  14.  
  15. Torque all head bolts in sequence, in three steps. Step 1: torque all bolts to 35 ft lbs. (47 Nm). Step 2: torque the bolts in sequence an additional 1 / 4 (90 degrees) turn. Step 3: once again, torque all bolts in sequence an additional 1 / 4 (90 degrees) turn. If torque reaches 65 ft lbs. (88 Nm) at any time, stop at this point. This torque specification must not be exceeded. Do not complete the balance of the 90 degree turn.
  16.  
  17. Install the exhaust manifolds.
  18.  
  19. Install the pushrods and rocker arm shafts.
  20.  
  21. Install the intake manifold, rocker arm cover and spark plug wires as outlined in this section.
  22.  
  23. Install the remaining components.
  24.  
  25. Install the drive belt and connect the negative battery cable.
  26.  
  27. Drain and refill the engine oil. Replace the oil filter, be sure to prime it with oil before installing.
  28.  
  29. Refill the cooling system, start the engine and check for leaks.
  30.  



Click image to see an enlarged view

Fig. Fig. 3: 3.8L cylinder head bolt torque sequence

5.0L and 5.7L Engines

See Figures 4 through 12



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Fig. Fig. 4: Pushrod removal-V8 engines



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Fig. Fig. 5: Removing the AIR tube clamp-V8 engines



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Fig. Fig. 6: AIR hose removal-V8 engines



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Fig. Fig. 7: Prying loose the head;V8 engines



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Fig. Fig. 8: Lifting off the head-V8 engines



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Fig. Fig. 9: Scraping off the old gasket material-V8 engines



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Fig. Fig. 10: Torquing the upper head bolts-V8 engines



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Fig. Fig. 11: Torquing the lower head bolts-V8 engines



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Fig. Fig. 12: Cylinder head bolt torque sequence-V8 engines

  1. Disconnect the negative battery cable. Drain the cooling system and relieve the fuel system pressure.
  2.  
  3. Raise and support the vehicle safely. Drain the engine oil and remove the oil filter. Lower the vehicle.
  4.  
  5. Remove the drive belt(s) and remove the intake manifold.
  6.  
  7. Remove the power steering pump, alternator bracket or the air conditioning compressor mounting bracket and position aside. Do not disconnect the lines from the air conditioning compressor.
  8.  
  9. Remove the exhaust manifolds and the valve covers.
  10.  
  11. Remove the rocker arms and pushrods.
  12.  
  13. Remove the cylinder head bolts and the cylinder head.
  14.  

To install:
  1. Clean the gasket mating surfaces of all components. Be careful not to nick or scratch any surfaces as this will allow leak paths. Clean the bolt threads in the cylinder block and on the head bolts. Dirt will affect bolt torque.
  2.  

When using a steel gasket, coat both sides of the new gasket with a thin even coat of sealer. If using a composition gasket, do not use any sealer.

  1. Position the head gasket over the dowel pins with the bead up. Install the cylinder head over the dowel pins and gasket.
  2.  
  3. Coat the threads of the head bolts with GM 1052080 thread sealer or equivalent. Install the head bolts and tighten in sequence, in three passes, to 65 ft lbs. (92 Nm).
  4.  
  5. Install the exhaust manifolds.
  6.  
  7. Install the pushrods and rocker arms, refer to the procedures outlined earlier in this section. Install the valve covers.
  8.  
  9. Install the power steering pump and alternator bracket or air conditioning compressor mounting bracket, as necessary.
  10.  
  11. Install the intake manifold.
  12.  
  13. Install the accessory drive belt(s).
  14.  
  15. Fill the cooling system with the proper type and amount of coolant. Connect the negative battery cable.
  16.  
  17. Raise and support the vehicle safely. Install a new oil filter, lower the vehicle. Fill the crankcase with the proper type and quantity of engine oil.
  18.  
  19. Start the engine, check for leaks and check the ignition timing.
  20.  

 
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