Operating instructions

May 1980 4-21
NOTE
Do not attempt to remove bolt and
washer adjacent to right magneto
upper stud. These two parts are
installed be- fore 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.
h. Lift off right crankcase. Lift out camshaft
assembly and governor driven gear (See Figure 4- 23).
Remove idler gear, crankshaft assembly with
connecting rods, thrust washers and main bearings
(See Figures 4-24 and 4-25).
i. Remove dowel pin (63) and idler gear bushing (64).
4-28. CAMSHAFT ASSEMBLY (See Figure 4-2)
a. Remove governor drive gear (2) and Woodruff key
(3).
b. Remove four screws (4) and lift off gear (5).
(IO-520-A only) and gear (6).
WARNING
Do not remove rear pipe plug (7) or
front expansion plug (8) from
camshaft in permold crankcase
engines.
4-29. CRANKSHAFT GROUP (Typical of Sand-
cast Crankcase) (See Figure 4-24).
a. Use wooden support blocks under front and rear
main journals of crankshaft during disassembly.
b. Remove cotter pin (5), slotted nut (6), bolt (7) and
separate connecting rod caps (8) and rods (9).
Remove all bearing inserts (10). Loosely reassemble
rods, caps, bolts and nuts with position numbers
matched.
c. Remove retaining rings (12), retaining plates (13)
and pins (14,15,16). Remove counterweights (17).
d. Remove nuts (19) and lift off governor oil transfer
collar (20 through 25).
e. Remove six screws (26), and pull gear (27) from
crankshaft.
f. Twist and remove split retainer ring, twist and
detach from seal (28). Work oil seal spring (29) from
its groove. Remove oil seal (30) from crank- shaft
(34).
4-30. CRANKSHAFT (Typical of Permold Crank-
case) (See Figure 4-25).
a. Use wooden support blocks under front and rear
journals of crankshaft during disassembly.
b. Remove cotter pin (4), slotted nut (5), bolt (6), and
separate connecting rod cap (7) and rod (8). Remove
bearing inserts (9). Loosely reassemble rod, cap, bolt
and nut with their position numbers matched.
c. Remove retaining ring (11), plate (12) and pins (13,
14, 15). Lift counterweight assemblies (16, 17) from
crankshaft (35).
d. Remove nuts (18) and separate governor oil
transfer collar (19 through 23) from crankshaft.
e. Remove six screws (24) and gear (25). Remove
four bolts (26), lockplate (27) and alternator drive gear
(28).
f. Twist and remove split retainer ring, twist and
detach from seal (29). Work oil seal spring (30) from
groove and detach from seal. Twist and remove oil
seal (31) from crankshaft.