low in the center lengthwise, gradually
decreasing toward the ends, or 0.003 inch
crosswise in localized low spots. Replace a
cracked, broken, or warped cylinder head.
c. Installation.
(1) Position a new cylinder head gasket (24, fig.
50) and cylinder head (21) on the block (28);
secure with the cylinder head nuts (8) and
washers (7). Tighten the nuts a little at a
time and in the sequence indicated in figure
58. Continue tightening in that rotation until
all cylinder head nuts are tightened to 70 to
75 foot-pounds torque.
(2) Position the thermostat housing (16, fig. 56)
and gasket (19) on the cylinder head.
Secure with two nuts (17) and lockwashers
(18).
(3) Install the spark plugs in the cylinder head.
(4) Fill the coolant system.
Figure 60. Removing valve guides.
116. Valve and Valve Tappets
a. Removal (fig. 59).
(1) Remove the cylinder head (para 115
a).
(2) Remove the valve chamber cover (para
(3) Using a spring lifter, compress the valve
spring (5) at each valve (2) and remove the
spring retaining locks (7) from each valve
that is in the closed position. Rotate the
engine crankshaft to close the remaining
valves and remove the remaining locks.
(4) Lift each valve from the top of the block.
Place them in order in a rack to assure that
each will be reassembled in the same valve
guide from which it was removed.
(5) Remove the valve stem caps (8). Remove
the valve tappet assemblies (9, 10, and 11).
(6) Do not remove the valve guides (4) or valve
seats (3) unless inspection indicates that
Figure 61. Valve guide location.
they are faulty.
(4) Inspect the valves for cracks, bent stems,
b. Cleaning, Inspection, and Repair.
distortion, and wear. If the valves are not
(1) Clean the valves, valve springs, valve
seriously damaged, regrind them. After
tappet assemblies, and valve stem caps
grinding, the valve head thickness must be
with an approved cleaning solvent; dry
at least 50 percent of the thickness of a new
thoroughly. Remove carbon deposits with a
valve.
Replace the valves if they are
wire brush.
ground to less than this amount. Check the
(2) Clean the valve guides installed in the block
reground valves on V-blocks with an
with a valve guide cleaner or wire brush.
indicator. The contact face must be true
Remove all lacquer and other deposits.
with the stem to within 0.002 inch. Repeat
(3) Clean the valve seats with a wire brush.
the refacing operation if necessary.
TAGO 6358-A
74
