TM 5-4320-218-15
(11) Install the spark plug in No. 1 cyl-
(4) Inspect the valves for burned, pitted,
inder.
or cracked faces; replace a burned,
c. Removal.
cracked, or deeply pitted valve.
(1) Remove the governor (par. 57c).
(5) Inspect the valve springs for brakes
and wear. Compare with a new
(2) Remove the cylinder heads (par.
spring and replace if weak or dam-
101a).
aged.
(3) Remove the valve covers (par.
(6) Inspect the valve seat inserts for loose-
102b).
ness and excessive wear,
(4) Use a valve spring compressor and
(7) Inspect and replace all unserivceable
compress the valve spring. Remove
parts.
the pair of valve spring seat locks, the
e. Valve and valve seat refacing.
valve stem roto cap, and valve spring
(1) Reface valves and valve seats only
seat. Remove the spring compressor,
when there is evidence of warping or
lift out the valve, and remove the
deep pits. A good method of detect-
valve spring.
ing warping is to check each valve
stem in a valve face grinder, and slow-
ly rotate the valve while the grinding
wheel is brought near the rotating
valve face.
d. Cleaning and inspection.
(2) Using a valve face grinder, reface the
(1) Clean the valves on a wire wheel brush
valves to an angle of 45 degrees. Re-
to remove carbon from the valve face
place any valve that measures less
and gum deposits from the stems.
than 0.0625 inch from the top of head
Wash the springs with an approved
to the edge of the refaced outer cir-
cleaning solvent, and dry thoroughly.
cle.
(2) Use a rifle brush to clean out the
(3) Install a pilot in the valve stem bore
valve guides in the cylinder block;
of the cylinder block. Set the stone
blow out with compressed air.
on the valve reseating outfit to the
(3) Clean the valve seat inserts and top
angle of 45 degrees and dress the
of the cylinder block.
stone with the dresser. Place the
grinder and stone assembly over the
pilot in the valve stem bore, and grind
just enough to make a smooth seat.
f. Valve grinding procedure.
(1) Remove all traces of cabon from the
face of the cylinder block.
(2) Lightly coat the entire valve seat
with a good quality water-soluble
valve grinding compound. Slip a
light lifting spring over the valve
stem, and lubricate the stem. Drop
the valve into its original place in the
cylinder block. The lifting spring
should barely hold the valve off its
seat. Set the grinding tool on the
valve head, and press down until the
valve is seated. Turn the valve one-
quarter turn, first in one direction.
Figure 31. Cylinder head tightening sequence.
then in the other. Do this three or
