TM 9-3431-254-14&P
automotive type ring compressor, and insert rod end
into cylinder from cylinder head end. Note: Rod bear-
ing should be parallel to flats at base of cylinder
barrel for correct assembly to crankshaft, see Fig.
bore. Use the wooden handle end of hammer, as shown
in Fig. B-49.
Replace valves that are burned or pitted. A leaky
valve can usually be determined by a `hissing' noise
in the exhaust or intake manifold when cranking the
engine slowly by hand.
The exhaust valves are furnished with positive type
rotators. Refer to Parts Section for mounting. The
valve rotates slightly each time it opens, and thereby
prevents the build up of foreign deposits on the valve
face and stem.
Valve grinding should be done by an authorized ser-
vice dealer, since he has the necessary equipment
and experience to do a good job. To remove valves;
use a standard automotive valve lifter as illustrated
in Fig. B-50, and remove spring seat locks. Release
valve lifter and take out valve, spring and exhaust
rotator or spring seat.
The valve face is ground at 45 to the vertical center
line of the valve stem and the valve seat insert
Piston and connecting rod is sub-assembled to the
should also be ground at a 45 angle. After grinding,
cylinder barrel and the complete unit is mounted to
valves and inserts should be lapped with a suitable
the crankcase. Lubricate the piston assembly and
lapping compound or they will leak due to improper
cylinder walls with No. 30 S.A.E. oil, and stagger
seating, within the first few hours of operation. While
the ring gaps 90 around the piston. Use a standard
lapping, occasionally lift the valves and reset them
2
9
B-30
