GM Service Manual Online
For 1990-2009 cars only

Valve Spring Tension Measurement Procedure


    Object Number: 4960  Size: SH
  1. Measure the valve spring tension using the J 9666 .
  2. Compare your measurements with the following specifications:
  3. RPO LD8 - VIN Y

    • Valve Closed: 205 N (46 lb) @ 30.3 mm (1.19 in)
    • Valve Open: 409 N (91 lb) @ 21.7 mm (0.854 in)

    RPO L37 - VIN 9

    • Valve Closed: 236 N (53 lb) @ 30.3 mm (1.19 in)
    • Valve Open: 485 N (109 lb) @ 20.9 mm (0.823 in)
  4. If low valve spring load is found, replace the valve springs. DO NOT use shims to increase spring load. The use of shims will cause the valve spring to bottom out before the camshaft lobe is at peak lift.