TM 5-3895-346-14
EXHAUST VALVES
ENGINE OVERHAUL
Figure 14. Grinding Wheel Dressing
Figure 15. Checking Relative
Tool of Set J 8165-1
Concentricity at Valve Seat Insert
with Relation to Valve Guide
relative to the valve guide. If the runout exceeds 0.002 inch, check for a bent valve guide before regrinding the
insert.
4. After the valve seat insert has been ground, determine the position of the contact area between the valve
and the valve seat insert as follows:
a. Apply a light coat of Prussian Blue or similar paste to the valve seat insert.
b. Lower the stem of the valve in the valve guide and bounce the valve on the seat. DO NOT ROTATE
THE VALVE. This procedure will show the area of contact (on the valve face). The most desirable area of
contact is at the center of the valve face.
CAUTION
The user of valve lapping compound is not recommended.
After the valve seat inserts have been ground and checked, thoroughly clean the cylinder head before installing
the valves.
Install Exhaust Valves and Springs
When installing exhaust valves, check to see that the valves are within the specifications shown in Fig. 13.
Also, do not use N-pistons with former four-valve cylinder head assemblies unless the valves are flush with the
cylinder head. If the valves are not flush, it may be necessary to regrind the valve seats so that the valves will
be flush with the bottom surface of the cylinder head.
NOTE
The distance from the top of the four-valve cylinder head to the bottom of the
valve spring seat counterbore is 1 11/64 inches in current design cylinder heads or
1 5/64 inches in former design heads.
Be sure and install the correct parts in the four-valve cylinder head. Current design cylinder heads are
equipped with the thin valve spring seats (0.060 inch) and current design exhaust valves
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