TM 5-3820-233-35/2
(2) Inspect the rocker arms for cracks breaks,
(2) Inspect teeth on the control rack and the
control rack gear for wear or other damage. Replace a
and other damage. Examine the bushing surfaces of
the rocker arms for excessive wear and scoring.
defective control rack or control rack gear.
Replace damaged or defective rocker arms.
(3) Test the follower spring compression.
(3) Inspect the rocker arms for wear, scoring,
When a 48 pound load is applied, the spring should
and ridges from the action of rocker arms on the shaft.
compress to a length of 1.028 inch. Replace a defective
Replace a damaged or defective rocker arm shaft.
or worn follower spring.
(4) Inspect push rods for warpage, cracks,
(4) Inspect all injector parts for wear and
breaks, and other damage.
Replace damaged or
damage.
defective push rods.
(5) Inspect the setting surfaces of the injector
(5) Inspect rocker arm shaft brackets and
body, bushing, valve seat, injector valve, valve spring,
rocker arm bushings for cracks, breaks, wear, and other
stop valve, valve cage, check valve, and spray tip with
damage. Replace damaged or defective parts.
a magnifying glass. If any imperfections are observed
the sealing surfaces using 600 grit dry lapping powder.
e. Reassembly. Reassemble the rocker arms and
(6) Before reassembling used valve parts in
shaft assembly in the reverse of the numerical sequence
the injector, lap all of the seating surfaces indicated in
as illustrated on figure 21-2.
step 5 above.
f. Installation
(7) (Clean all lapped parts with an approved
(1) Refer to figure 21-1 and install the rocker
cleaning solvent, and dry thoroughly.
arms and shaft assembly.
f. Reassembly. Reassemble the fuel injector in
(2) Refer to the Operator' Manual and install
s
the reverse of the numerical sequence as illustrated on
the injector fuel connector, and rocker arm cover.
(3) Refer to the Operator' Manual, and
s
g. Installation and Timing. Refer to the Operator's
adjust valves and injectors.
Manual.
43.
Cylinder Head and Valves
42.
Rocker Arms and Shaft
a. General. The cylinder head is a one piece
a. General. The rocker arm assemblies actuate
casting which can be removed from the engine as an
the valves and fuel injectors. The two outer rocker arms
assembly. Located on the cylinder head are the cam
operate the exhaust valves and the center rocker arm
followers and guides, push rods, rocker arms, exhaust
operates the fuel injectors.
The rocker arms are
valves and injectors. The cylinder head is secured to
operated by the camshaft through push rods and cam
the top of the engine block by studs and bolts.
followers.
(1) Drain the cooling system (Operator'
s
b. Removal
Manual).
(1) Refer to the Operator's Manual and
(2) Remove the muffler and air cleaner
remove the rocker arm cover, injector fuel lines, and
(Operator' Manual).
s
fuel connectors.
(3) Remove the hoods, side panels, and tie
(2) Refer to figure 21-1 and remove the
rods (Operator' Manual).
s
rocker arms and shaft.
(4) Remove the rocker arm cover (Operator'
s
c. Disassembly. Disassemble the rocker arms and
Manual).
shaft assembly in the numerical sequence as illustrated
(5) Remove the exhaust manifold (para 40).
on figure 21-2.
(6) Disconnect the throttle control rods at the
d. Cleaning, Inspection, and Repair
governor (Operator' Manual).
s
(1) Clean all parts with an approved cleaning
(7) Remove the water manifold, thermostat
solvent and dry thoroughly.
housing, and bypass tube (Operator' Manual).
s
3-25
