b. Cleaning, Inspection and Repair.
exceeds 0.002 inch, repeat the grinding operation or
(1) Clean all parts.
replace inserts. Grind each valve in its respective seat
(2) Inspect for cracks or other defects. Rep
and insert to assure a gastight fit.
c. Installation.
defective parts.
(3) Measure valve guides for excessive wear
Inside diameter should be 0.3422-to 0.3432-inch].
NOTE
Replace a guide that is worn to 0.3447 inch.
(4) Measure valve spring length in valve closed
Chill the exhaust valve seat inserts for several
position which should be 1 21 / 32 inches and ] 47-to
minutes to shrink their diameters and permit
53-pounds. Measure valve spring length in the valve-
them to be more easily driven into their
open position which should be 13/8 inches and the load
respective counterbores. Be sure the valve seat
103-to 110-pounds.
Replace springs that do not
insert is properly seated against bottom of
conform to the above requirement
counterbore. Drive valve guides from top of
(5) Measure the intake valve stem diameter should
block to a depth of 1-15/32 inches, measured
be 0.3406-to 0.3414-inch. If valve stem is worn to
from top of guide to top of cylinder block. When
0.3386 inch or less, replace valve.
replacing ferox-coated guides, do not ream; the
(6) Measure the exhaust valve stem diameter It
guides are prereamed before coating. Further
should be 0.3357-to 0.3385-inch. If valve stem is worn
reaming removes the coating.
to 0.3357 inch or less, replace valve.
(7) Grind both valve seats and faces required. The
(1) Reassemble and install valves, guides, and
intake valve seat angle and intake valve face angle are
lifters as shown in figures 5-8 and 5-7.
30. Exhaust valve seat angle is 45. Measure angles
(2) Adjust valves (TM 10-3950-203-20).
(3) Install cylinder head (TM 10-3950-203-20).
with a line at right angles to the stem. Check face with
(4) Install valve cover (TM 10-3950-203-20).
center line of stem using a dial indicator. Runout on the
valve faces must not exceed 0.002 inch. If the runout
5-8. Pistons and Connecting Rods
exceeds this amount, repeat grinding or replace valves
a. Removal.
necessary. Measure distance from outside of valve
(1) Remove cylinder head (TM 10-3950-203-20).
faces to the top of the valve. If this distance one-half or
(2) Remove oil pump (para 5-6).
less than that of a new valve, replace valve.
(3) Refer to figure 5-9 and remove cotter pin (2),
(8) Reface the exhaust valve seat inserts with
nut (3), lower connecting rod cap (5) and lower bearing
suitable refacing tool according to directions furnished.
Correct seat insert angle is 45. Grind new face to a
sleeve (6).
(4) Push connecting rods (5) up and remove
width of 1 / 16-to 3 / 32-inch. Check valve seat faces
upper bearing sleeve (6).
with a dial indicator. If runout
(5) Wrap bottom of rods (5), to prevent damage to
cylinder walls, and then push the connecting rods, with
pistons attached, up and out of cylinders.
(6)
Remove
rings
(8)
and
complete
disassembly
as
shown.
5-9
