Removal (see figure 7-9).
(1) Remove. Refer to the Operator and
Organizational Maintenance Manual and remove air
shutter assembly and intake and exhaust manifold,
muffler and shroud assembly. Remove engine lifting
bracket, rocker cover and gasket, fuel nozzles, and
connecting oil lines to cylinder head.
(2) Remove rocker arms by removing the self-
locking rocker arm nuts (1, figure 7-9), rocker arm
balls (2) on each rocker arm (3). Lift rocker arm (3)
(3) Remove capscrews (4) and push rod guide
plate (5), screws (6) and washers (7) holding each
cylinder head (8) to cylinder block (9).
(4) Remove push rod (15) and remove cylinder
heads. If heads stick, rap sharply with a soft hammer.
DO not use a pry. Do not strike the cooling fins.
(5) Remove push rod shield (17) and packings (16),
spring (18) and washers (19).
(6) Remove cylinder head gaskets (10).
b. Disassembly (see figure 7-11).
(1) Remove valve rotator (l). Using a valve
spring compressor (see figure 7-10), disassemble
valve assemblies. Valve assemblies include spring
retainer lock (2), (see figure 7-11), retainer (3), valve
spring (5) and valves (8) and 10).
(2) Remove intake valve seals (4).
c. Clean and Inspect. Thoroughly clean all compo-
nents of cylinder head assemblies. Remove all carbon
deposits from intake and exhaust ports and clean all
gasket surfaces. Inspect all cylinder head components
for physical damage. Inspect cylinder head firing deck
for warpage by measuring the maximum gap between
the cylinder head and a steel straightedge placed in
line and at a right angle to the cylinder head. If the
gap exceeds 0.0015 in any direction, replace cylinder
(1) Valves. Remove all carbon and check each
valve (8 and 10, figure 7-11) for burning, pitting or
warped head. Valves that are slightly pitted or burned,
refinish on a valve grinder. Refinish intake valves to
a 44 angle and exhaust valves to a 45° angle. But, if
they are badly pitted, or will have a thin edge when
refacing, replace them. Check refinished valves for a
tight seat to the valve seat (7) with an air pressure
type testing tool or by applying Prussian Blue on the
valve face and rotating it against the seat.
(2) Valve Guides. Check valve guides (6 and 9,
figure 7-11) to valve clearance. See table 1-2. If the
proper clearance cannot be obtained by replacing
valve, replace valve guides. Drive the old valve guides
into valve chambers. Drive new intake guides (6) in
until the y protrude 11/32 inch from the rocker cover
side of the head. Ream new valve guide to obtain the
proper clearance. Exhaust guides (9) should protrude
5/8 inch from rocker cover side of the head.
(3) Valve Seats. If the valve seats (7, figure
7-11) are pitted, refinish them. Using seat grinding
equipment, reface each seat to a 45° angle. Seat width
should be 3/64 to 1/16 inch for exhaust and 1/16 to
3/32 for intake. A seat can be refaced several times
before it becomes necessary to replace it. If, how-
ever, the valve seats are loose or cannot be refaced,
replace them. Adjust tool to cut 1/64 inch from edge
of seat. Oil the pilot to prevent it from seizing in the
valve guide. Cut each seat down to a narrow ridge on
edges and bottom and break it out with a sharp tool.