GM Service Manual Online
For 1990-2009 cars only

Tools Required

    • J 7872 Magnetic Base Dial Indicator Set
    • J 26900-2 Outside Micrometer
  1. Inspect the camshaft journals and the lobes for wear or for scoring.

  2. Object Number: 262331  Size: SH
  3. Using an outside micrometer, measure the height of the intake lobes and of the exhaust lobes.
  4. Standard Camshaft Intake Lobe Height
    36.171-36.331 mm (1.4241-1.4303 in)

    Minimum Camshaft Intake Lobe Height
    36.071 mm (1.4202 in)

    Standard Camshaft Exhaust Lobe Height
    36.356-36.516 mm (1.4314-1.4376 in)

    Minimum Camshaft Exhaust Lobe Height
    36.256 mm (1.4275 in)

  5. Replace the camshaft, if any of the camshaft lobes which you measured are not within the specifications.

  6. Object Number: 262334  Size: SH
  7. Place the camshaft in two V-Blocks, and use a dial indicator in order to measure the runout of the camshaft.
  8. Camshaft Runout
    Maximum = 0.10 mm (0.0039 in)


    Object Number: 262269  Size: SH
  9. Inspect the cylinder head for scoring in the camshaft journals.

  10. Object Number: 262337  Size: SH
  11. Inspect the camshaft journal caps for scoring (1).
  12. Clean the cylinder head.
  13. • Wash the cylinder head in solvent.
    • Inspect the cylinder head for cracks or for other signs of damage.