Valve and Valve Guide Inspection
Precautions: General safety (00)
Valve Guide
Valve stem-to-guide clearance
Using a micrometer and bore gauge, take diameter readings on valve stems and guides to check stem-to-guide clearance.
Take reading at more than one place along the length of each stem and guide.
If clearance is not as specified, replace valve and/or valve guide.
Valve stem diameter [A]
In: 4.982 – 5.000 mm (0.1961 – 0.1968 in.)
Ex: 4.972 – 4.990 mm (0.1957 – 0.1964 in.)
Valve guide bore [B]
In and Ex: 5.015 – 5.033 mm (0.1974 – 0.1981 in.)
Stem-to-guide clearance
In: 0.015 – 0.051 mm (0.00059 – 0.00200 in.)
Ex: 0.025 – 0.061 mm (0.00098 – 0.00240 in.)
Valve
Visual inspection
•Remove all carbon deposits from valves.
•Check each valve for wear, burn or distortion at its face. If any abnormality is found, replace valve.
•Check valve stem end for pitting or wear. If any abnormality is found, valve stem end can be resurfaced to a certain extent. If it is worn out badly, replace valve.
•Check each valve for wear, burn or distortion at its face. If any abnormality is found, replace valve.
•Check valve stem end for pitting or wear. If any abnormality is found, valve stem end can be resurfaced to a certain extent. If it is worn out badly, replace valve.
Valve seat
| Item | Specification | |
|---|---|---|
| Valve seat angle “a” | Intake valve | 44° – 46° |
| Exhaust valve | ||
| Valve seat outside diameter “b” | Intake valve | 28.355 – 28.365 mm (1.1163 – 1.1167 in.) |
| Exhaust valve | 26.100 – 26.111 mm (1.0275 – 1.0279 in.) |
|
Valve guide outside diameter “a”
| Standard | 10.010 – 10.030 mm (0.39410 – 0.39488 in.) |
| Oversize | + 0.05 mm (0.0020 in.) |
| + 0.10 mm (0.0039 in.) | |
| + 0.25 mm (0.0098 in.) |
