Pontiac Fiero 1984-1988 Repair Guide

Cylinder Head

Print

REMOVAL & INSTALLATION



4-2.5L Engine


Click image to see an enlarged view

Fig. Fig. 1 Cylinder head components and bolt locations-four-cylinder engines



Click image to see an enlarged view

Fig. Fig. 2 Cylinder head bolt tightening sequence-2.5L engine



Click image to see an enlarged view

Fig. Fig. 3 When removing nuts, bolts and other parts, place them in a tray or other container


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 negative (-) battery cable.
  2.  
  3. Drain the cooling system at the radiator into a suitable drain pan.
  4.  
  5. Raise the vehicle and support it safely with jack stands.
  6.  
  7. Remove the exhaust pipe.
  8.  
  9. Lower the vehicle.
  10.  
  11. Remove the oil level indicator tube.
  12.  
  13. Remove the air cleaner assembly.
  14.  
  15. Disconnect the EFI electrical connections and vacuum hoses.
  16.  
  17. From the throttle body; remove the wiring connectors, throttle linkage and fuel lines.
  18.  


CAUTION
To reduce the risk of fire and personal injury, it is necessary to relieve the fuel system pressure before servicing any fuel system component. If this procedure is not performed, fuel may be sprayed out of the connection under pressure. Always keep a dry chemical (Class B) fire extinguisher near the work area.

Fuel pressure relief procedures:

    1. Remove the fuel pump fuse from the fuse block located in the passenger compartment.
    2.  
    3. Start the engine and run until the engine stops due to the lack of fuel.
    4.  
    5. Crank the engine for 3 seconds to ensure all pressure is relieved.
    6.  


  1. Remove the EGR base plate.
  2.  
  3. Remove the heater hose from the intake manifold.
  4.  
  5. Remove the ignition coil from the lower mounting bolt and wiring connection.
  6.  
  7. Remove all wiring and vacuum connections from the intake manifold and cylinder head.
  8.  
  9. Remove the engine strut bolt from the upper support.
  10.  
  11. Remove the alternator belt and brackets to move the alternator out of the way.
  12.  
  13. Remove the air conditioning brackets and swing the air conditioning compressor aside if top mounted.
  14.  


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. Remove the exhaust pipe-to-exhaust manifold attaching bolts.
  2.  
  3. Remove the valve cover, rocker arms and pushrods. Refer to the Rocker Arm Cover and Pushrod removal and installation procedures in this section.
  4.  

Mark each valve component to ensure that they are replaced in the same location as removed. This is very important because each component will follow different wear patterns.

  1. Remove the cylinder head bolts and remove the cylinder head and manifolds as an assembly. If the cylinder head has to be serviced, the manifolds will have to be removed from the cylinder head.
  2.  

To install:

  1. Before installing, clean the gasket surfaces of the head and block.
  2.  
  3. Check the cylinder head for warpage using a straight edge. Refer to the Cylinder Head Resurfacing procedures in this section.
  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 in the sequence shown in the illustration. Refer to the Torque Specifications chart in the beginning of this section for proper specs and procedures depending on the year of your Fiero.
  14.  
  15. Install the pushrods, rocker arms and nuts (or bolts) in the same location as removed. Torque the nuts (or bolts) to 24 ft. lbs. (32 Nm).
  16.  
  17. Install the rocker arm cover as outlined in the Rocker Arm Cover removal and installation procedures in this section.
  18.  
  19. Install the radiator hose and clamps, alternator bracket and belt and adjust the belt to 130 lbs. (600 N) for a new belt, and 70 lbs. (300 N) for a used belt.
  20.  
  21. Install the alternator bracket and bolt.
  22.  
  23. Install the air conditioning compressor and bracket (if to mounted).
  24.  
  25. Install the strut rod bolt.
  26.  
  27. Connect all wiring connectors to the intake manifold and cylinder head.
  28.  
  29. Install all vacuum and heater hoses to the intake manifold.
  30.  
  31. Install the wiring, throttle linkage and fuel lines to the throttle body assembly.
  32.  
  33. Install the dipstick tube, air cleaner and refill the engine with the specified engine coolant.
  34.  
  35. Raise the vehicle and support with jackstands.
  36.  
  37. Install the exhaust pipe to exhaust manifold and torque the bolts to 25 ft. lbs. (34 Nm).
  38.  
  39. Install the oxygen sensor connector, lower the car and connect the negative (-) battery cable. Check for completion of repair. Start the vehicle and check for fuel, vacuum, coolant and exhaust leaks.
  40.  

6-2.8L Engine
LEFT CYLINDER HEAD


Click image to see an enlarged view

Fig. Fig. 4 Cylinder head components and bolt tightening sequence-2.8L engine

  1. Disconnect the negative (-) battery cable.
  2.  
  3. Raise the vehicle and drain the coolant from the block.
  4.  


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. Lower the vehicle.
  2.  
  3. Remove the intake manifold as outlined in the Intake Manifold removal and installation procedures in this section.
  4.  


CAUTION
To reduce the risk of fire and personal injury, it is necessary to relieve the fuel system pressure before servicing any fuel system component. If this procedure is not performed, fuel may be sprayed out of the connection under pressure. Always keep a dry chemical (Class B) fire extinguisher near the work area.

  1. Fuel pressure relief procedures: connect a fuel gauge part No. J 34730-1 or equivalent to the fuel pressure valve on the fuel rail assembly. Wrap a towel around the fitting while connecting the gauge to prevent fuel spillage. Install the bleed hose into an approved container and open the valve to bleed the system pressure.
  2.  
  3. Disconnect the exhaust crossover pipe as outlined in the "Crossover Pipe" procedures in this section.
  4.  
  5. Disconnect the alternator bracket.
  6.  
  7. Remove the oil dipstick tube.
  8.  


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. Remove the rocker arm cover as outlined in the Rocker Arm Cover (Left) procedures.
  2.  
  3. Loosen the rocker arms until you're able to remove the pushrods. Mark each valve component so to ensure proper installation.
  4.  
  5. Raise the vehicle and support with jackstands.
  6.  
  7. Remove the bolts retaining the exhaust manifold-to-crossover pipe.
  8.  
  9. Remove the cylinder head bolts then remove the cylinder head.
  10.  

To install:

  1. Before installing, clean the gasket surfaces on the head, cylinder block and intake manifold with a gasket scraper and solvent.
  2.  
  3. Match the new gasket with a old one to ensure an exact match. Place the gasket in position over the dowel pins with the note "This Side UP" showing.
  4.  
  5. Place the cylinder head into position.
  6.  
  7. Coat the cylinder head bolt threads with a sealer GM 1052080 or equivalent and install the bolts. Torque the bolts in sequence shown in the following illustration. For torque specifications, refer to the Torque Specifications chart in the beginning of this section for the proper specs and procedures depending on the year of your Fiero.
  8.  
  9. Install the pushrods and loosely retain with the rocker arms. Make sure the lower ends of the pushrods are in the lifter seats then adjust the valve lash as shown below:
  10.  
    1. Valve Lash Adjustment: rotate the engine until the mark on the torsional damper lines up with the "0" mark on the timing tab, with the engine in the No. 1 firing position. This may be determined by placing fingers on the No. 1 rocker arms as the mark on the damper comes near the "0" mark. If the valves are not moving, the engine is in the No. 1 firing position. With the engine in the No. 1 firing position, the following valves may be adjusted:

      Exhaust-1, 2, 3
       
      Intake-1, 5, 6
       

    2.  
    3. Back out the adjusting nut until lash is felt at the pushrod, then turn the adjusting nut until all lash is removed. This can be determined by rotating the pushrod while turning the adjusting nut. When lash has been removed, turn the adjusting nut in 1 1 / 2 additional turns to center the lifter plunger.
    4.  
    5. Crank the engine one revolution until the timing tab "0" mark and torsional damper mark are again in alignment. This is the No. 4 firing position. With the engine in this position, the following valves may be adjusted;

      Exhaust-4, 5, 6
       
      Intake-2, 3, 4
       

    6.  
    7. For further valve adjustment illustrations, refer to the Rocker Arm Cover procedures in this section.
    8.  
    9. Install the intake manifold assembly as outlined in the Intake Manifold procedures in this section. Also, refer to the Torque Specifications chart for proper specs and procedures for your year Fiero.
    10.  
    11. Install the oil dipstick tube, heat stove pipe and air supply pipe.
    12.  
    13. Raise the vehicle and support with jackstands.
    14.  
    15. Install the exhaust pipe to the exhaust manifold. Torque the attaching bolts to 25 ft. lbs. (34 Nm).
    16.  
    17. Install all vacuum, heater and wire connectors to the intake manifold and cylinder head.
    18.  
    19. Install the air conditioning compressor and alternator. Adjust the belts to specification. 135 lbs. (600 N) for a new belt, and 70 lbs. (300 N) for a used belt.
    20.  
    21. Install the air cleaner assembly, reconnect the negative (-) battery cable and recheck for completion of repair. Start the engine and check for vacuum, oil, fuel, exhaust and coolant leaks.
    22.  


RIGHT CYLINDER HEAD


Click image to see an enlarged view

Fig. Fig. 5 Loosen the rocker arm nuts, then ...



Click image to see an enlarged view

Fig. Fig. 6 ... remove the pushrods from the engine



Click image to see an enlarged view

Fig. Fig. 7 Tag the pushrods and keep them in the order of their removal



Click image to see an enlarged view

Fig. Fig. 8 Remove the intake manifold gaskets



Click image to see an enlarged view

Fig. Fig. 9 Use a socket and a box end wrench when disconnecting the exhaust pipe from the manifold



Click image to see an enlarged view

Fig. Fig. 10 Remove the cylinder head bolts, then lift the cylinder head off the engine block



Click image to see an enlarged view

Fig. Fig. 11 Use a gasket scraper to clean the old gasket material from the engine block



Click image to see an enlarged view

Fig. Fig. 12 Use a torque wrench to tighten the head bolts in the proper sequence to the exact specification

  1. Disconnect the negative (-) battery cable.
  2.  
  3. Raise the vehicle, support it safely with jackstands.
  4.  
  5. With a drain pan under the radiator drain plug, drain the cooling system.
  6.  


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 exhaust pipe from the exhaust crossover pipe.
  2.  
  3. Lower the vehicle.
  4.  
  5. Disconnect the cruise control servo bracket.
  6.  
  7. Release the fuel pressure and remove the intake manifold. Refer to the Intake Manifold procedures in this section.
  8.  


CAUTION
To reduce the risk of fire and personal injury, it is necessary to relieve the fuel system pressure before servicing any fuel system component. If this procedure is not performed, fuel may be sprayed out of the connection under pressure. Always keep a dry chemical (Class B) fire extinguisher near the work area.

  1. Fuel pressure relief procedures: connect a fuel gauge part No. J 34730-1 or equivalent to the fuel pressure valve on the fuel rail assembly. Wrap a towel around the fitting while connecting the gauge to prevent fuel spillage. Install the bleed hose into an approved container and open the valve to bleed the system pressure.
  2.  
  3. Disconnect the exhaust crossover pipe from the exhaust manifold.
  4.  


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. Remove the rocker arm cover as outlined in the Rocker Arm Cover procedures in this section.
  2.  
  3. Loosen the rocker arm nuts far enough to remove the pushrods. Mark each valve component to ensure proper installation into the same location as removed.
  4.  
  5. Remove the cylinder head bolts and the cylinder head.
  6.  

To install:

  1. Clean the gasket surfaces on the cylinder head, intake manifold and cylinder block with a gasket scraper and solvent.
  2.  
  3. Check the cylinder head for flatness with a straight edge. Refer to the Cylinder Head Cleaning and Inspecting procedures in this section.
  4.  
  5. Match the new gasket with a old one to ensure an exact match. Place the gasket in position over the dowel pins with the note "This Side UP" showing.
  6.  
  7. Place the cylinder head into position.
  8.  
  9. Coat the cylinder head bolt threads with a sealer GM 1052080 or equivalent and install the bolts. Torque the bolts in sequence shown in the following illustration. For torque specifications, refer to the Torque Specifications chart in the beginning of this section for the proper specs and procedures depending on the year of your Fiero.
  10.  
  11. Install the pushrods and loosely retain with the rocker arms. Make sure the lower ends of the pushrods are in the lifter seats then adjust the valve lash as shown below:
  12.  
    1. Valve Lash Adjustment: rotate the engine until the mark on the torsional damper lines up with the "0" mark on the timing tab, with the engine in the No. 1 firing position. This may be determined by placing fingers on the No. 1 rocker arms as the mark on the damper comes near the "0" mark. If the valves are not moving, the engine is in the No. 1 firing position. With the engine in the No. 1 firing position, the following valves may be adjusted:

      Exhuast-1, 2, 3
       
      Intake-1, 5, 6
       

    2.  
    3. Back out the adjusting nut until lash is felt at the pushrod, then turn the adjusting nut until all lash is removed. This can be determined by rotating the pushrod while turning the adjusting nut. When lash has been removed, turn the adjusting nut in 1 1 / 2 additional turns to center the lifter plunger.
    4.  
    5. Crank the engine one revolution until the timing tab "0" mark and torsional damper mark are again in alignment. This is the No. 4 firing position. With the engine in this position, the following valves may be adjusted:

      Exhuast-4, 5, 6
       
      Intake-2, 3, 4
       

    6.  
    7. For further valve adjustment illustrations, refer to the "Rocker Arm Cover" procedures in this section.
    8.  
    9. Install the intake manifold assembly as outlined in the Intake Manifold procedures in this section. Also, refer to the Torque Specifications chart for proper specs and procedures for your year Fiero.
    10.  
    11. Install the cruise control servo bracket, if so equipped.
    12.  
    13. Raise the vehicle and support with jackstands.
    14.  
    15. Install the exhaust crossover pipe to the exhaust manifold. Torque the attaching bolts to 25 ft. lbs. (34 Nm).
    16.  
    17. Lower the vehicle.
    18.  
    19. Install all vacuum, heater and wire connectors to the intake manifold and cylinder head.
    20.  
    21. Install the air conditioning compressor and alternator. Adjust the belts to specification. 135 lbs. (600 N) for a new belt, and 70 lbs. (300 N) for a used belt.
    22.  
    23. Install the air cleaner assembly, reconnect the negative (-) battery cable and recheck for completion of repair. Start the engine and check for vacuum, oil, fuel, exhaust and coolant leaks.
    24.  


CLEANING & INSPECTION





Click image to see an enlarged view

Fig. Fig. 13 Using a straightedge and a feeler gauge to check cylinder head flatness



Click image to see an enlarged view

Fig. Fig. 14 A wire wheel may be used to clean the combustion chambers of carbon deposits



Click image to see an enlarged view

Fig. Fig. 15 Checks should be made both straight across the cylinder head and at both diagonals


CAUTION
To avoid personal injury ALWAYS wear safety glasses when using a power drill and wire brush.

  1. Remove all traces of carbon from the head, using a decarbon-type wire brush mounted in an electric drill. Do not use a motorized brush on any gasket mating surface.
  2.  
  3. Lay a straightedge across the cylinder head face and check between the straight edge and the head with feeler gauges. Make the check at six points minimum. Cylinder head flatness should be within 0.003-0.006 inch. These surfaces may be reconditioned by parallel grinding. This procedure must be done by a qualified machine shop. If more than 10% must be removed, the head should be replaced.
  4.