Operating instructions

4-20
i. Remove hydraulic valve lifter assemblies (43). It is
recommended that all hydraulic lifters be replaced at
each major overhaul regardless of condition. If for
any reason lifters are removed for inspection before
the overhaul period is reached, they must be placed
back in the same location from which they were
removed.
4-26. SANDCAST CRANKCASE (See Figure 4-
21).
a. Oil gauge rod and guide and brackets (items 1
through 11) are shipped loose with the engine, and
were probably returned in the same manner. If not,
remove in the order of index numbers assigned.
b. Unhook filler cap retaining ring and remove oil cap
retainer assembly (12). Remove three screws (14) and
lift off oil filler neck (15) and gasket (16).
c. Remove attaching parts (17,18,19,20) and remove
lifting eye (21) and spacer (22).
d. Cut lockwire and remove oil temperature con- trol
valve (23).
e. Remove bolt (24), nut (27), lockwashers (25), plain
washer (26), plain washer (28), flanged nut (29) and
washer (30) to remove generator mount bracket (31).
f. Remove nut (32), lockwasher (33), plain washer
(30), spacer (35) and lift off governor pad cover (36)
and gasket (37).
g. Remove parts indexed (38 through 49).
h. Rotate engine disassembly stand bed so that left
crankcase (82) will be downward and support it as
illustrated in Figure 8-1.
i. Remove remaining crankcase-to-crankcase flange
bolts (50), nuts (51), lockwashers (52) and plain
washers (53).
NOTE
Do not attempt to remove bolt and
washer adjacent to right magneto up- per
stud. These two parts are installed before
the stud and cannot be removed before
removal of that stud without damage to
crankcase hole. Take care to avoid
damage to bolt threads during
subsequent overhaul operations.
j. With a non-marring hammer, tap upper ends of
through bolts(54,55,56,57) and pull them downward
and out of the crankcase. Discard "O" rings.
k. Remove idler gear support pin attaching parts (58,
59) and hold idler gear while support pin (60) is
withdrawn. Lower gear to rest in left crankcase.
Remove gasket (61).
1. Remove attaching parts (62, 63, 64) and re- move
mounting brackets (65).
m. Lift off right crankcase subassembly.
n. Lift out camshaft assembly and governor driven
gear (See Figure 4-23).
o. Lift out idler gear assembly, crankshaft assembly
with connecting rods, thrust washers and bearings
(See Figure 4-19).
4-27. PERMOLD CRANKCASE (See Figure 4-
22).
a. Remove oil gauge rod (1). Remove attaching parts
(2, 3, 4) and detach oil filler tube (5), gasket (6) and
“O” ring (7).
b. Remove nut (8), washers (9, 10), bolt (11), lifting
eye (12) and spacer (13).
c. Remove nut (14), washers (15, 16), spacer (17) and
lift off governor pad cover (18) and gasket (19).
d. Remove camshaft hole cover attaching parts (20,
21, 22), cover (23) and gasket (24).
e. Rotate engine stand bed to place left crank- case
downward. Place a length of pipe or wood under the
left crankcase to support it during disassembly.
Remove right mount brackets (IO- 520-C only).
f. Remove two sets of attaching parts (25, 26), idler
gear flanged bushing (27) and gasket (28).
g. Remove attaching parts (29 through 57). Tap
crankcase through bolts (58 through 61) with a non-
marring hammer and remove carefully from crankcase
so as not to damage threads. Remove "O" rings (47).