TM 5 3810-294-34
a. Remove crown nuts (1), washers (2) and lift
surface.
cylinder head cover (3). Remove gasket (4).
d. Examine cylinder head for signs of cracks or sand
b. Remove bolts (5), studs (6), and washers (7 and 8)
holes. Check the areas around exhaust valve ports for
from rocker arm shaft brackets. Remove the rocker arm
indications of blow-by. Check cylinder head for warpage
assembly as a unit and oil bolt (9) and gasket (10).
(refer to table 1-4) for tolerances.
Remove pushrods (11).
e. Examine rocker arm shaft expansion plugs. Check
the shafts on a surface plate for signs of bending, also
Note. Mark pushrods for installation in identical
check for wear from rocker arms. Examine all rocker
position at reassembly.
arm parts for wear.
4-9. Repair and Replacement
c. Remove head bolts (12 and 13) and washers (14
a. Refer to TM 5-3810-294-34P for repair parts.
and 15).
b. Replace all gaskets, seals, and unserviceable
d. Using lifting eye (16), remove head (17) and gasket
parts.
(18). Remove oil tube (19).
c. Valve faces may be ground provided adequate
4-6. Disassembly
valve margin remains after grinding. Refer to table 1-4
Refer to figure 4-1 and disassemble head, valves, and
for proper valve face angle. Replace worn or burned
rocker arm as follows:
valves.
a. Remove exhaust valve tip cup (20). Compress
d.
Replace weak, broken or distorted springs.
valve spring with a valve compressor and remove valve
Replace damaged or distorted spring retainers.
spring retainer lock (21). Remove retainer (22), inner
e. Replace worn or damaged valve seat rings.
spring (23), outer spring (24), and lower spacer (25).
f. If clearance between rocker arm bushing and shafts
b. In like manner, remove retainer lock (26) from
exceeds 0.004 inch, replace bushings.
intake valve (28), retainer (27), inner spring (23), outer
g. Repair or replace cylinder head if machine surfaces
spring (24), and lower spacer (25).
are marred, damaged, or warped beyond limits shown in
c. Remove intake valves (28) and exhaust valves
(29). Remove valve guides (30 and 31). Remove valve
4-10. Reassembly and Installation
seat rings (33 and 34). Remove tappets (35).
Refer to figure 4-1 and reassemble and install head,
d. Remove retainer (36), washer (37) and spring (38).
rocker arm, and valves as follows:
Remove adjustment nut (39), adjustment screw (40), and
a. Chill valve seat rings (33 and 34) in dry ice for at
rocker arm (41).
least one-half hour before installation. Use an arbor
e. Remove bushing (42) from bracket (43). Slide
press and driver to insert the rings into the cylinder head.
spring (44) from shaft and remove plug (45). Remove
An evenly applied 500 pound load is required for proper
shaft (46), coupling (47), and shaft (48). Remove oil
installation. Maintain 500 pound load for five seconds to
connector (49).
assure proper seating.
4-7. Cleaning
Note. Do not install inserts by hammering or
a. Clean all metal parts in dry cleaning solvent
striking insert driver. After insert is installed do not peen
(Federal Specification P-S-661) and dry thoroughly.
the head metal over the edge of the insert. Replace with
Coat all machine surfaces with light oil to prevent rusting.
new valve seat rings.
b. Clean all oil passages with brass probes and flush
with cleaning solvent. Blow dry with compressed air.
b. Install valves (28 and 29) in cylinder head. Install
c. Scrape all remaining gasket material and carbon
lower spacers (25), inner spring (23), outer spring (24)
from parts. Use care so as not to damage sealing
and retainers (22 and 27). Compress springs and install
surfaces.
locks (21 and 26). Install cup (20) on exhaust valve (29).
d. Clean valves with a soft wire buffer to remove
c. Install gasket (18) on engine. Install tappets (35).
carbon. Ream carbon from valve guides.
Using lifting eye (16), set cylinder head (17) in place.
4-8. Inspection
Install oil tube (19) in head.
a. Examine valve and valve seats for pitting, burning,
d. Install pushrods (11) into the head, being certain
warping and other defects.
that they enter the valve tappets and that each is in the
b. Examine valve springs for indications that the oil
same position as before. Install bolts (12 and 13) and
passages to the valve levers may be blocked causing
washers (14) and hand tighten. Tighten all bolts to a
wear on the valves and guides. Check for dry and rusted
torque of 100 foot-pounds according to the sequence
valve springs.
Test each spring against the
shown in figure 4-2.
specifications (refer to table 1-4).
c.
Check all valve lifter rods by rolling on a flat
4-3
