TM 5-3805-280-24-2
Cylinder Head and Valves
05
3. Using drill from JT05893 Heavy Duty Seat Grinder Set,
37
grind valve seats to the following specifications:
Valve Seat Grinding--Specification
Valve Seat Angle (D)............................................................................. 30
Valve Seat Width (E)........................... 1.50--2.00 mm (0.059--0.079 in.)
Maximum Valve Seat Runout (F)............................... 0.08 mm (0.003 in.)
4. Use a vernier caliper or scale to measure seat width. If
valve seat is too wide, reduce the width with a
narrowing stone.
NOTE: A narrowing stone will change the top angle of the
D--Valve Seat Angle
seat and reduce the outer diameter of the valve
E--Valve Seat Width
seating area. Varying the width changes the fine
F--Valve Seat Runout
contact between valve face and seat. If seat width
is too narrow, valve may burn or erode.
RG,05,DT7353 1911NOV973/4
5. If valve does not seat properly, use an eccentrimeter
(A) to check valve seat runout. Use a new or refaced
valve and blueing to check contact between valve seat
and face. If necessary, lap the valve onto its seat using
a lapping tool and lapping compound. Replace valves
and inserts as necessary.
6. Install new or refaced valve and check valve recess in
cylinder head after grinding. (See CHECK VALVE
RECESS IN CYLINDER HEAD earlier in this group.)
A--Eccentrimeter
RG,05,DT7353 1911NOV974/4
13-95