crankshaft.
One bolt hole is offset so
CRANKSHAFT TIMING GEAR
the gear can be attached in only one po-
sition.
Description
2. Align the "R" timing mark on the
crankshaft gear tooth with the corre-
The crankshaft timing gear is bolted to
sponding mark on the idler gear.
the flange at the rear of the crankshaft
and drives the camshaft gears, through
an idler gear.
3. Start the six 3/8"-24 bolts with lock
washers through the gear and into the
Since the camshaft must be in time with
crankshaft.
Then draw the gear tight
the crankshaft, timing marks are located
against the shoulder on the crankshaft.
on two teeth of the idler gear with corre-
Tighten the bolts to 35-39 lb-ft (47-53
Nm) torque.
sponding timing marks stamped on the
crankshaft gear and camshaft.
4. Check the backlash with the mating
The backlash should be 0.003" to
gear.
0.008" with new gears or 0.010" maximum
R e m o v e Crankshaft Timing Gear (Fly-
with used gears.
w h e e l Housing Removed)
The crankshaft gear is press fit on the
5. Install a new crankshaft rear oil seal
c r a n k s h a f t . Remove the gear as follows:
sleeve, if required.
1. Remove the crankshaft rear oil seal
sleeve, i f u s e d .
To remove the sleeve,
B L O W E R DRIVE GEAR AND SUPPORT
peen the outside diameter of the sleeve
ASSEMBLY
until it stretches sufficiently so it can be
slipped off of the crankshaft.
Description
2. Before removing the crankshaft gear,
align the timing marks of the gear train
The blower drive gear is mounted on the
and note their location so the gear can
blower drive gear support and in addi-
be reinstalled in its original position.
tion to driving the blower, drives the
governor, water pump and fuel pump.
3. Remove the six bolts and lock washers
The drive is cushioned by a spring load-
securing the gear to the crankshaft.
ed flexible coupling, see Figure 11B-169
on page 11B-112 and Figure 11B-173 on
4. Provide a base for the puller screw by
page 11B-115, which insures a uniform
placing a steel plate across the cavity in
rotation of the blower rotors. The right
t h e e n d o f t h e c r a n k s h a f t . The remove
hand helix blower drive gear is driven
the gear with a suitable puller as shown
the
balance
shaft gear
(see
by
in Figure 11B-168.
The
ratio of blower speed to engine speed is
1 . 5 5 to 1.
Inspection
Clean the gear with fuel oil and dry it
with compressed air.
Examine the gear
teeth for evidence of scoring, pitting or
If severely damaged or worn, in-
wear.
stall a new gear.
Also check the other
gears in the gear train.
I n s t a l l Crankshaft Timing Gear
1. Position the gear on the rear of the
crankshaft with the flat finished hub of
the gear facing toward the cylinder block
and with all six bolt holes in the gear
aligned with the tapped holes in the
F i g u r e 11B-168. Removing Crankshaft
T i m i n g Gear
Engine (Less Major Assemblies)
