TM 5-3810-300-24&P-3
Cylinder Head 1.2
Fig. 11 - Minimum Distance Between Top and Bottom
Faces of Cylinder Head
e. If the pressure check revealed any cracks, install a
new cylinder head.
2. Check the bottom (fire deck) of the cylinder head for
flatness:
a. Use a heavy, accurate straight-edge and feeler
gages, tool J 3172, to check for transverse warpage at
each end and between all cylinders. Also check for
longitudinal warpage in six places as shown in Fig. 10.
4. Inspect the exhaust valve seat inserts and valve
Refer to Table I for maximum allowable warpage.
b. Use the measurements obtained and the limits
5. Inspect the cam follower bores in the cylinder head
given in Table I as a guide to determine the advisability
for scoring or wear. Light score marks may be cleaned
of re-installing the head on the engine or of refacing it.
up with crocus cloth wet with fuel oil. Measure the bore
The number of times a cylinder head may be refaced will
diameter. The cam follower-to-cylinder head clearance
depend upon the amount of stock previously removed.
must not exceed .006 " with used parts (refer
c. If the head is to be refaced, remove the injector
tubes prior to machining. Do not remove more than
.020" (total) of metal from the fire deck of any cylinder
head. The distance from the top deck to the bottom (fire
deck) of the cylinder head must not be less than 3.536"
(Fig. 11). Stamp the amount of stock removed on the
face of the fire deck near the outer edge of the head, in
an area not used as a sealing surface.
CAUTION: When a cylinder head has been refaced,
critical dimensions such as the protrusion of valve seat
inserts, exhaust valves, injector tubes and injector spray
tips must be checked and corrected. The push rods
must also be adjusted to prevent the exhaust valves
from striking the pistons after the cylinder head is re-
installed in the engine.
3. Install new injector tubes (Section 2.1.4) if the old
tubes leaked or the cylinder head was refaced.
Fig. 13 - Correct Installation of Water Nozzles in Four-
Valve Cylinder Head
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