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Home >> Pontiac >> 2009 >> Vibe Base, 2.4 0, AWD >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 6 (Engine Mechanical - 1.8L (Lay)) >> Repair Instructions - Off Vehicle >> Cylinder Head Cleaning and Inspection

Cylinder Head Cleaning and Inspection

WARNING: This page is about a different variant/trim than selected.
    Fig 1: Inspecting Cylinder Head For Flatness
    GM2017183Courtesy of GENERAL MOTORS CORP.
  1. Inspect cylinder head for flatness.
  2. Using a precision straight edge and a feeler gauge, measure the surfaces contacting the cylinder block and the manifolds for warpage.
  3. If the warpage is greater than the maximum, replace the cylinder head.
    4. Fig 2: Inspecting Intake/Exhaust Ports For Cracks
    GM2017184Courtesy of GENERAL MOTORS CORP.
  4. Using a dye penetrant, check the intake ports, exhaust ports and cylinder surface for cracks. If cracked, replace the cylinder head.
    5. Fig 3: Identifying Valve Face
    GM2017185Courtesy of GENERAL MOTORS CORP.
  5. Apply a light coat of Prussian blue to the valve face.
  6. Lightly press the valve face against the valve seat.
  7. Check the valve face and valve seat according to the following procedure:
    1. If Prussian blue appears 360 degrees around the valve face, the valve face is concentric. If not, replace the valve.
    2. If Prussian blue appears 360 degrees around the valve seat, the guide and valve face are concentric. If not, resurface the valve seat.
    3. Check that the valve seat contact is in the middle of the valve face with the valve seat width between 1.0 and 1.4 mm (Intake side - 0.039 to 0.055 in).
    4. Check that the valve seat contact is in the middle of the valve face with the valve seat width between 1.0 and 1.4 mm (Exhaust side - 0.039 to 0.055 in).
  8. Install the camshafts.
    9. Fig 4: Measuring Thrust Clearance While Moving Camshaft Back & Forth
    GM2017186Courtesy of GENERAL MOTORS CORP.
  9. Using a dial indicator, measure the thrust clearance while moving the camshaft back and forth.
  10. If the thrust clearance is greater than the maximum, replace the camshaft housing. If the thrust surface is damaged, replace the camshaft.
  11. Inspect camshaft oil clearance.
  12. Clean the bearing caps and camshaft journals.
  13. Place the camshafts on the camshaft housing.
    14. Fig 5: Applying Plastigage Across Camshaft Journal
    GM2017187Courtesy of GENERAL MOTORS CORP.
  14. Lay a strip of Plastigage across each of the camshaft journals.
    15. NOTE: Do not turn the camshaft.
  15. Install the bearing caps.
  16. Remove the bearing caps.
    17. Fig 6: Measuring Plastigage At Widest Point
    GM2017188Courtesy of GENERAL MOTORS CORP.
    NOTE: Completely remove the Plastigage after the inspection.
  17. Measure the Plastigage at its widest point.
  18. If the oil clearance is greater than the maximum, replace the camshaft. If necessary, replace the cylinder head.
    19. Fig 7: Inspecting Compression Spring
    GM2017190Courtesy of GENERAL MOTORS CORP.
  19. Inspect compression spring.
  20. Using vernier calipers, measure the free length of the valve spring.

    Specification:  Free length: 53.36 mm (2.1008 in)

  21. If the free length is not as specified, replace the valve spring.
    22. Fig 8: Measuring Spring Deviation
    GM2017191Courtesy of GENERAL MOTORS CORP.
  22. Using a steel square, measure the deviation of the valve spring.

    Specification:  Maximum deviation: 1.0 mm (0.0394 in)

  23. If the deviation is greater than the maximum, replace the valve spring.
    24. Fig 9: Cleaning & Inspecting Valve
    GM2017192Courtesy of GENERAL MOTORS CORP.
  24. Inspect intake valve.
  25. Using a gasket scraper and wire brush, scrape off any carbon on the valve head.
    26. Fig 10: Measuring Overall Valve Length
    GM2017193Courtesy of GENERAL MOTORS CORP.
  26. Using vernier calipers, measure the overall length of the valve.

    Specification: 

    • Standard overall length: 109.34 mm (4.3047 in).
    • Minimum overall length: 108.84 mm (4.2850 in).

  27. If the overall length is less than the minimum, replace the valve.
    28. Fig 11: Measuring Valve Stem Using Micrometer
    GM2017194Courtesy of GENERAL MOTORS CORP.
  28. Using a micrometer, measure the diameter of the valve stem.

    Specification:  Valve stem diameter: 5.470 to 5.485 mm (0.2154 to 0.2159 in)

  29. If the valve stem diameter is not as specified, check the oil clearance.
    30. Fig 12: Identifying Valve Head Margin Thickness
    GM2017195Courtesy of GENERAL MOTORS CORP.
  30. Using vernier calipers, measure the valve head margin thickness.

    Specification: 

    • Standard margin thickness: 1.0 mm (0.0394 in)
    • Minimum margin thickness: 0.5 mm (0.0197 in)

  31. If the margin thickness is less than the minimum, replace the valve.
    32. Fig 13: Cleaning & Inspecting Valve
    GM2017192Courtesy of GENERAL MOTORS CORP.
  32. Inspect the exhaust valve.
  33. Using a gasket scraper and wire brush, scrape off any carbon on the valve head.
    34. Fig 14: Measuring Overall Valve Length
    GM2017196Courtesy of GENERAL MOTORS CORP.
  34. Using vernier calipers, measure the overall length of the valve.

    Specification: 

    • Standard overall length: 109.34 mm (4.3047 in)
    • Minimum overall length: 108.84 mm (4.2850 in)

  35. If the overall length is less than the minimum, replace the valve.
    36. Fig 15: Measuring Valve Stem Using Micrometer
    GM2017198Courtesy of GENERAL MOTORS CORP.
  36. Using a micrometer, measure the diameter of the valve stem.

    Specification:  Valve stem diameter: 5.470 to 5.485 mm (0.2154 to 0.2159 in)

  37. If the valve stem diameter is not as specified, check the oil clearance.
    38. Fig 16: Measuring Valve Head Margin
    GM2017199Courtesy of GENERAL MOTORS CORP.
  38. Using vernier calipers, measure the valve head margin thickness.

    Specification: 

    • Standard margin thickness: 1.0 mm (0.0394 in)
    • Minimum margin thickness: 0.5 mm (0.0197 in)

  39. If the margin thickness is less than the minimum, replace the valve.
    40. Fig 17: Inspecting Valve Guide Bush Oil Clearance
    GM2017200Courtesy of GENERAL MOTORS CORP.
  40. Inspect valve guide bush oil clearance.
  41. Using a caliper gauge, measure the inside diameter of the guide bush.

    Specification:  Bushing inside diameter: 5.510 to 5.530 mm (0.2169 to 0.2177 in)

  42. Subtract the valve stem diameter measurement from the guide bush inside diameter measurement.
  43. If the clearance is greater than the maximum, replace the valve and guide bush.
    44. Fig 18: Inspecting Cylinder Head Set Bolt
    GM2017112Courtesy of GENERAL MOTORS CORP.
  44. Inspect the cylinder head set bolt.

    Using vernier calipers, measure the length of the cylinder head set bolt from the seat to the end.

    If the bolt length is greater than the maximum, replace the cylinder head set bolt.

    Specification: 

    • Standard bolt length: 146.8-148.2 mm (5.7795-5.8346 in)
    • Maximum bolt length: 149.2 mm (5.874 in)

    45. NOTE: Using a straightedge, visually check the thinner areas of the threaded part of the cylinder head set bolt.
  45. Using vernier calipers, measure the minimum diameter of the elongated thread at the measuring point.

    If the diameter is less than the minimum, replace the cylinder head set bolt.

    Specification:  Maximum warpage: 0.7 mm (0.028 in)

Maximum Warpage

Item Specified Condition
Cylinder block side 0.05 mm (0.0020 in)
Intake manifold side 0.10 mm (0.0039 in)
Exhaust manifold side 0.10 mm (0.0039 in)
Standard Thrust Clearance

Item Specified Condition
Intake 0.06 to 0.155 mm (0.0024 to 0.0061 in)
Exhaust 0.06 to 0.155 mm (0.0024 to 0.0061 in)
Maximum Thrust Clearance

Item Specified Condition
Intake 0.17 mm (0.0067 in)
Exhaust 0.17 mm (0.0067 in)
Standard Oil Clearance

Item Specified Condition
Camshaft No. 1 journal 0.085 mm (0.0033 in)
Camshaft other journals 0.09 mm (0.0035 in)
Maximum Oil Clearance

Item Specified Condition
Intake 0.080 mm (0.0031 in)
Exhaust 0.085 mm (0.0033 in)
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