GM Service Manual Online
For 1990-2009 cars only

Tools Required

J 7872 Magnetic Base Dial Indicator


    Object Number: 60261  Size: SH
  1. Attach theJ 7872 to the front of the engine cylinder block.
  2. • Position the magnetic base dial indicator to allow the plunger to contact the timing chain.
    • The magnetic base dial indicator plunger should contact the timing chain centered between the two sprockets.
  3. Using finger pressure on the inside radius of the timing chain, push the timing chain outward (parallel to the front face of the block) to the maximum deflection.
  4. Set theJ 7872 to zero.
  5. Using finger pressure on the outside radius of the timing chain, push the timing chain inward (parallel to the front face of the block) to the maximum deflection.
  6. Note the deflection of the timing chain (total travel of the magnetic base dial indicator plunger).
  7. • For used parts, the deflection must not exceed 20.3 mm (0.80 in).
    • For new parts, the deflection must not exceed 12.7 mm (0.50 in).
  8. If the deflection exceeds the limit, replace the worn parts. Refer to Timing Chain and Sprockets Clean and Inspect .