GM Service Manual Online
For 1990-2009 cars only

Tools Required

J 7872 Magnetic Base Dial Indicator Set


    Object Number: 637692  Size: SH
  1. Clean the camshafts with cleaning solvent.
  2. Inspect the camshafts for the following conditions:
  3. • Scored camshaft journals
    • Damaged camshaft lobes
    • Damaged camshaft sprocket locator pin and slots
    • Damaged threads
  4. Measure the camshaft lobes using a micrometer. The intake camshaft lobes should be a minimum of 41.5 mm (1.635 in). The exhaust camshaft lobes should be a minimum of 41 mm (1.615 in).

  5. Object Number: 637693  Size: SH
  6. Use J 7872 to measure the camshaft runout.
  7. 4.1. Set the camshaft in V-blocks between the centers.
    4.2. Measure the intermediate camshaft journal.
  8. Use J 7872 to measure the camshaft lobe lift.
  9. 5.1. Lubricate the camshaft to V-block contact areas with engine oil.
    5.2. Set the camshaft on V-blocks.
    5.3. Measure the camshaft lobe lift.
  10. If the runout or camshaft lobe lift is not within specifications, replace the camshaft.