GM Metro/Sprint 1985-1993 Repair Guide

Cylinder Head

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REMOVAL and INSTALLATION

See Figures 1, 2 and 3



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Fig. Fig. 1: Cylinder head gasket installation



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Fig. Fig. 2: Cylinder head tightening sequence - Metro



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Fig. Fig. 3: Cylinder head tightening sequence - Sprint

  1. On fuel injected vehicles, relieve the fuel system pressure.
  2.  
  3. Disconnect the negative battery cable.
  4.  
  5. Drain the cooling system.
  6.  


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. Label and disconnect all necessary electrical connectors.
  2.  
  3. Label and disconnect all necessary vacuum, fuel and water hoses.
  4.  
  5. Remove the intake manifold with the carburetor or throttle body installed.
  6.  
  7. Remove the exhaust manifold.
  8.  
  9. Remove the timing belt and belt tensioner.
  10.  
  11. Remove the distributor cap, then mark the position of the rotor and the distributor housing with the cylinder head. Remove the distributor and the case from the cylinder head.
  12.  
  13. Remove the cylinder head cover.
  14.  
  15. Loosen and remove the cylinder head bolts in the reverse order of the tightening sequence.
  16.  
  17. Remove the cylinder head from the engine. Discard the cylinder head gasket.
  18.  

To install:
  1. Install the cylinder head gasket with the TOP indicator facing upward and to the crankshaft pulley side.
  2.  
  3. Install the cylinder head and eight cylinder head bolts. Lubricate the head bolts with engine oil prior to installation.
  4.  
  5. Tighten cylinder head bolts in the proper sequence to 54 ft. lbs.. (73 Nm). Repeat tighten sequence several times before reaching specified torque figure.
  6.  
  7. Install rubber seals between the water pump and the cylinder head.
  8.  
  9. Install the cylinder head cover and secure with nuts and new seal washers. Tighten nuts to 44 inch lbs.. (5 Nm).
  10.  
  11. Install timing belt and tensioner.
  12.  
  13. Install the distributor, aligning the matchmarks made during removal.
  14.  
  15. Install the intake manifold.
  16.  
  17. Install the exhaust manifold.
  18.  
  19. Connect all previously removed electrical connectors.
  20.  
  21. Connect all previously removed vacuum, fuel and water hoses.
  22.  
  23. Adjust the accessory drive belt tension.
  24.  
  25. Adjust the accelerator cable play.
  26.  
  27. Refill the cooling system.
  28.  
  29. Connect the negative battery cable.
  30.  
  31. Start the engine and allow it to reach operating temperature.
  32.  
  33. Check for leaks.
  34.  
  35. Make any necessary adjustments.
  36.  

CLEANING AND INSPECTION



Do not use any sharp edged tool to scrape carbon from the head. Be careful not to scuff or nick the metal surfaces when decarboning. This could lead to leakage and reduced power output.

  1. Disassemble the cylinder head, clean with solvent and air dry thoroughly. Remove all carbon from the combustion chambers.
  2.  
  3. Check the cylinder head for cracks in intake and exhaust ports, combustion chambers and head surface.
  4.  

RESURFACING



See Figures 4 and 5

All cylinder head resurfacing operations should be performed by a qualified machine shop; only the cylinder head inspection is recommended to be performed by the home mechanic.



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Fig. Fig. 4: Locations for measuring cylinder head gasket surface distortion



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Fig. Fig. 5: Measuring the cylinder head surface with a straightedge and feeler gauge.

  1. Check the flatness of the cylinder head gasket surface. Using a straight edge and feeler gauge, check surface at a total of six locations.
  2.  
  3. If distortion exceeds the 0.0002 in. (0.05mm) limit at any location, resurfacing of the head is necessary.
  4.  
  5. If distortion cannot be brought within limits, replace the cylinder head.
  6.  

Leakage of combustion gases from this gasket joint is often due to a warped gasket surface. Leakage results in reduced power output.

  1. Check for distortion of the manifold seating faces. Using a straight edge and feeler gauge, check the seating faces of the intake and exhaust manifolds-to-cylinder head to determine whether these faces can be corrected or if the cylinder head must be replaced.
  2.  
  3. If measurement after any correction exceeds 0.004 in. (0.10mm), replace the cylinder head.
  4.  

 
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