Valves and Valve Guides Inspection
Valve stem-to-guide clearance
Using a micrometer and bore gauge, take diameter readings on valve stems and guides to check stem-to-guide
Be sure to take reading at more than one place along the length of each stem and guide.
If clearance exceeds limit, replace valve and valve guide.
Valve stem and valve guide specification
Valve stem diameter [A]
Valve guide bore [B]
Valve stem end deflection
If bore gauge is not available, check end deflection of
valve stem with a dial gauge instead.
Move stem end in directions (1) and (2) to measure end
If deflection exceeds its limit, replace valve stem and
Valve stem end deflection limit
In: 0.14 mm (0.005 in.)
Ex: 0.18 mm (0.007 in.)
5.465 – 5.480 mm (0.2150 – 0.2157 in.)
5.440 – 5.455 mm (0.2142 – 0.2148 in.)
In & Ex
5.500 – 5.512 mm (0.2165 – 0.2170 in.)
0.020 – 0.047 mm (0.0008 – 0.0018 in.)
0.045 – 0.072 mm (0.0017 – 0.0028 in.)
• Remove all carbon from valves.
• Inspect each valve for wear, burn or distortion at its
face and stem end, as necessary, replace it.
• Inspect valve stem end face for pitting and wear. If
pitting or wear is found there, valve stem end may be
resurfaced, but not too much to grind off its chamber.
When it is worn out too much that its chamber is gone,
0.070 mm (0.0028 in.)
0.090 mm (0.0035 in.)