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Subtract the valve stem outside diameter from the
valve guide inside diameter to determine the valve
guide-to-stem clearance.
If the measurement exceeds the service limit,
replace the valve guide and/or the valve.
Valve Guide-to-Stem Clearance
IN
Standard
EX
IN
Service Limit
EX
If the valve guide inside diameter cannot be mea-
sured, use a dial gauge to check the valve stem
end deflection to determine whether the valve
guide-to-stem clearance is adequate.
•
Install the valve into the valve guide.
•
Position the valve head approximately 0.2 in.
(5.0 mm) away from the valve seat.
•
Move the stem end back and forth and measure
the deflection.
If the measurement exceeds the service limit,
replace the valve. If the measurement still
exceeds the service limit with a new valve
installed, replace the valve guide.
Valve Stem End Deflection
IN
Service Limit
EX
0.0008 – 0.0019 in.
(
)
0.020 – 0.047 mm
0.0014 – 0.0024 in.
(
)
0.035 – 0.062 mm
(
)
0.0028 in.
0.070 mm
(
)
0.0035 in.
0.090 mm
0.006 in. (0.14 mm)
0.007 in. (0.18 mm)
001493
Inspect the valve stem end face for pitting and
wear. The valve stem end may be refaced. Be
careful not to wear down the chamfer too far.
Use vernier calipers to measure the valve stem
end length. If the measurement is less than the
specification, the chamfer is too worn. Replace
the valve.
Valve Stem End Length
IN
Service Limit
EX
Valve Guide Replacement
Use a valve guide remover to drive out the valve
guide from the combustion chamber side of the
cylinder head toward the valve spring side.
IMPORTANT:
Do not reuse a valve guide once
it has been removed. Always use a new oversize
valve guide when assembling.
POWERHEAD
CYLINDER HEAD
0.276 in. (7.00 mm)
0.236 in. (6.00 mm)
001494
001504
143
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