Valve Guide: Testing and Inspection

CLEARANCE
1. Measure valve deflection as shown in illustration. The valve and valve guide mostly wear in this direction. The valve deflection limit (dial gauge reading) is 0.2 mm (0.008 inch.)
2. If it exceeds the limit, check the valve to valve guide clearance.
a. Measure valve stem diameter and valve guide inner diameter.





b. Calculate valve to valve guide clearance. Valve to valve guide clearance equals (=) valve guide inner diameter minus (-) valve stem diameter:
Intake standard clearance is 0.020 - 0.053 mm (0.0008 - 0.0021 inch.)
Exhaust standard clearance is 0.040 - 0.073 mm (0.0016 - 0.0029 inch).
The limit for the intake is 0.08 mm (0.0031 inch.)
The limit for the exhaust is 0.1 mm (0.004 inch.)
c. If it exceeds the limit, replace valve and remeasure clearance.
3. If clearance still exceeds the limit after replacing valve, replace valve guide.