TM 9-4520-251-14
6-4 VALVES, VALVE SEATS, AND GUIDE (CONT)
Location/Item
Action
Remarks
exhaust valve and valve seat to 45° angle, and in-
take valve and valve seat to 30° angle. Lap with
fine lapping compound (Item 7, Appendix E) to
remove grinding marks. Surfaces of both valve
seats should be 3/64 to 1/16 inch (1.19 to 1.58 mm)
wide. If seat is wider, a narrowing stone or cutter
should be used. Valve margin must be greater than
1/64 inch (0.4 mm) after refacing. If either seat or
valve is badly burned, or margin is 1/64 inch (0.4
mm) or less, replace.
NOTE
Apply antiseize compound (Appendix E, Item 1) to valve stems and guides
(5 and 6) before installing. Be sure no compound is on ends of valve stems
or tappets.
2.
Guide (ex–
If flat end of reject gauge can be inserted into
haust valve)
guide (5) a distance of 5/16 inch (7.94 mm)
guide is worn and should be replaced.
6-5
