Operating instructions

7-4 JANUARY 1985
7-13. CRANKSHAFT AND CONNECTING
RODS -TYPICAL OF SANDCAST CRANKCASE
(See Figure 4-24).
a. Lay crankshaft on a bench with a notched wood
block under front and rear journals.
b. Layout connecting rods, caps, bolts and nuts (9, 8,
7, 6) opposite crankpins according to position number
stamped on bolt bosses. Install new bearing insert in
each rod and cap so their ends project the same
distance.
c. Lubricate and install each rod and cap with position
numbers on top when odd number rods are extended
to the right and even numbers to the left. Attach them
with special bolts (7) and slotted nuts (6). Tighten
nuts to specified torque and secure each with a cotter
pin (5).
d. Attach two sixth order counterweights (17) to
crankcheek No.2 with two pins (14) each and install
retaining plates and rings (13, 12). Attach one fourth
order and one fifth order counterweight to crankcheek
No.5. Install pins (15, 16) and se- cure with plates (13)
and retaining rings (12). Install retaining rings with
the flat or rough side to the outside.
e. Heat crankshaft gear (27) to 300° F., align gear
dowel hole with crankshaft dowel (32) and tap gear
onto crankshaft. Attach gear to shaft with six screws
to specified torque and secure head with lockwire.
f. Remove spring and reinforcing ring from oil seal.
Unhook the spring ends using an unwinding motion.
Wrap spring around shaft in seal area, turn spring ends
in an unwinding direction, then join and allow one end
to wind into the other end. Oil propeller flange, shaft
and I.D. of seal liberally with clean engine oil.
Squeeze oil seal until egg-shaped and start seal over
propeller flange, groove side toward the rear. Work
seal carefully, to prevent damage to the lip, upward
over the flange. Placing a lightly oiled plastic bag
over the prop flange will help protect the seal. Also, a
special tool, Borrough's Tool and Equipment
Company P/N 5209, is available (See Section III).
After the seal is on the shaft, wipe any oil from the
O.D. of the seal. The O.D. of the seal is to be dry
when installed in the crankcase. No sealing cement or
compound is to be used. Install the reinforcing ring,
working O.D. of seal over ring to insure a snug fit.
Install spring in cavity in seal.
g. Install governor oil transfer collar (20 through 25)
and secure with nuts (19).
FIGURE 7-2. ALTERNATOR DRIVE GEAR INSTALLED.
7-14. CRANKSHAFT AND CONNECTING
RODS -TYPICAL OF PERMOLD CRANKCASE
(See Figure 4-25).
a. Paragraphs a, b, c, d, e and f of 7-13 also apply to
the IO-520-C crankshaft and all of the foregoing
paragraphs except "d" shall also apply to the IO-520-
B.
The IO-520-B has been modified by the use of three
(3) sixth order counterweights and one (1) fourth order
counterweight.
This modification requires a change to the name plate
which consists of an "A" stamped after the model
designation.
b. Heat alternator gear (28) in oven at 300° F. for half
hour or more and install on crankshaft (See Figure 7-
2). Secure with four bolts (26).
NOTE
Install gear in proper position so that
timing marks are in line with the No.2
throw when at TDC.