Valve Spring Inspection

Valve Spring Inspection

Valve and Cylinder Head Disassembly and Reassembly

Valve Spring Free Length and Preload

- Check each valve spring for breakage or weakening.
- Measure valve spring free length and preload.
Replace valve spring if measured value is less than limit.

NOTE:
Weakened valve springs can cause chatter, not to mention possibility of reducing power output due to gas leakage caused by decreased seating pressure.

Valve spring free length "a"
Standard: 51.34 mm (2.021 in.)
Limit: 50.34 mm (1.981 in.)

Valve spring preload when compressed to 41.0 mm (1.61 in.)
Standard: 170 - 196 N (17.4 kgf - 19.9 kgf, 125.5 lbf - 144.0 lbf)
Limit: 165 N (16.9 kgf, 37.1 lbf)

Valve spring preload when compressed to 31.2 mm (1.22 in.)
Standard: 379 - 437 N (38.7 - 44.5 kgf, 279.5 - 322.0 lbf)
Limit: 375 N (38.2 kgf, 277.0 lbf)









Spring Squareness

Use a square surface plate to check each spring for squareness in terms of clearance between end of valve spring and square. Valve springs found to exhibit a larger clearance than limit must be replaced.

Valve spring squareness
Limit: 2.2 mm (0.086 in.)