36
①
OD of valve stem
Use a micrometer to check the outer diameter of valve stem. If the diameter is lower than
standard or exceeds the maintenance limit, or the valve surface has visible ablation or cracks,
replace it with a new valve.
Standard
Maintenance limit
Inlet: 6.563-6.575 mm
Exhaust: 6.548-6.56 mm
6.418 mm
6.375 mm
②
Free length of valve spring
Measure free length of valve spring.
If it is below the standard or exceeds service limits,
replace the spring.
Standard
Maintenance limit
39.5 mm
38 mm
③
Valve guide
Inspection:
a) Check if inner surface of valve guide is smooth, being free of scratches and scuffing; the
fitting between valve guide and valve seat is solid.
b) Before measuring the ID of the valve guide
pipe, remove carbon deposit inside valve
guide pipe by valve guide reamer.
Reamer of valve
guide pipe
