GM Service Manual Online
For 1990-2009 cars only

    Object Number: 1224677  Size: SH
  1. Weakened valve springs can be the cause of chatter, not be mentioned to possibility of reducing the power output due to gas leakage caused by decreased seating pressure.
  2. Free length of the valve spring (1).
  3. Replace the valve springs of which valve spring free length is less than the limit.
  4. Specifications

        • The valve spring free length standard is 54.45 mm (2.1437 in).
        • The valve spring free length limit is 53.40 mm (2.1024 in).

    Object Number: 1224679  Size: SH
  5. Replace the valve springs of which valve spring preload (1) is less than the limit.
  6. Specifications
    The valve spring preload standard is 23.4-27.0 mm (0.9213-1.0630 in).

  7. Measure the spring squareness of each spring using a flat plate and the square.

  8. Object Number: 1224682  Size: SH
  9. Replace the valve spring of which clearance is over the limit.
  10. Specifications
    The valve spring squareness limit is 2.4 mm (0.0945 in).