Valve: Testing and Inspection

Valve Guide Clearance:

1. Measure valve deflection in a right-angled direction with camshaft. (Valve and valve guide mostly wear in this direction.)
Valve deflection limit (Dial gauge reading):
0.15 mm (0.0059 in)

Valve Stem Diameter:

2. If it exceeds the limit, check valve to valve guide clearance.
- Measure valve stem diameter and valve guide inner diameter.
- Check that clearance is within specification.
Valve to valve guide clearance:
Intake: 0.020 - 0.053 mm (0.0008 - 0.0021 in)
Limit: 0.1 mm (0.004 in)

Exhaust: 0.040 - 0.070 mm (0.0016 - 0.0028 in)
Limit: 0.1 mm (0.004 in)

3. Check valve seats for any evidence of pitting at valve contact surface, and reseat or replace if it has worn out excessively.

Valve Seat Face Angles:

4. Check valve seating condition.
Seat face angle: 45°.

Contacting width "W":
Intake: 1.6 - 1.7 mm (0.063 - 0.067 In)

Exhaust: 1.7 - 2.1 mm (0.067 - 0.083 In)

Valve Margin Thickness:

5. Check dimensions in each valve. When valve head has been worn down to:
0.5 mm (0.020 in) in margin thickness, replace valve.

6. Grinding allowance for valve stem tip is:
0.2 mm (0.008 in) or less.