1
2
1
A
B
2
TM 9-4940-568-34
7-21
(28)
Install valves in their respective bores and
measure depth again.
(29)
Record depth of each valve as B, and
calculate grinding depth GD = B – A. The
grinding depth limit is 0.010 in. (0.25 mm).
NOTE
The service valve seats are
available for over the limit seats.
(30)
Mark cylinder head to identify re-ground
valve seats.
(31)
If removed, install valves in their
designated location and measure depth
again. Refer to Step (25) for correct valve
depth. Replace valve if depth is over limit.
(32)
Apply a light coat of valve lapping
compound to each valve and lap each valve
to its companion seat.
Ensure all lapping compound is
cleaned from valves and seats.
Failure to do so will cause serious
damage to cylinder head and
valves.
(33)
Remove valves and clean lapping
compound from valves and seats.
(34)
Measure valve seat width indicated by
lapped surface. Valve seat minimum width
(1) limit is 0.060 in. (1.5 mm) and
maximum width (2) is 0.080 in. (2.03 mm).
(35)
If required, grind area (A) with a 60-degree
stone and (B) with a 15-degree stone to
center seat on valve face. Maintain valve
seat width limits referred to in Step (34).
