1. Measure: valve-stem-to-valve-guide clearance
Valve-stem-to-valve-guide clearance = Valve guide inside diameter (a) - Valve stem diameter (b)
Out of specification Replace the valve guide.
Valve-stem-to-valve-guide clearance:
- Intake 0.010-0.037 mm
- Limit: 0.08 mm
- Exhaust 0.025-0.052 mm
- Limit: 0.10 mm
2. Replace: valve guide
Note: To ease valve guide removal and installation, and to maintain the correct fit, heat the cylinder head to 100°C (212°K) in an oven.
a. Remove the valve guide with a valve guide remover (1).
b. Install the new valve guide with a valve guide installer (2) and valve guide remover (1).
c. After installing the valve guide, bore the valve guide with a valve guide reamer (3) to obtain the proper valve-stem-to-valve-guide clearance.
Note: After replacing the valve guide, reface the valve seat.
Valve guide remover and installer (8 mm): 90890-04014
3. Eliminate: carbon deposits (from the valve face and valve seat)
4. Check:
- valve face. Pitting/wear → Grind the valve face.
- valve stem end. Mushroom shape or diameter larger than the body of the valve stem → Replace the valve.
5. Measure: valve margin thickness (a)
Out of specification → Replace the valve.
- Valve margin thickness limit: 0.8 mm
6. Measure: valve stem runout
Out of specification → Replace the valve.
Note:
- When installing a new valve, always replace the valve guide.
- If the valve is removed or replaced, always replace the valve stem seal.
- Valve stem runout: 0.03 mm