CRANKSHAFT
-
3/16"
(4.763
mrn)
A585
7
DURING
SHOT- PEENINti
OPERATION
II
THIS AREATO
BE
MASKED
DURING
SHOT- PEENINti
OPERATION
FIGURE
61.
REMOVING CRANKSHAFT GEAR
FIGURE
62.
SHOT-PEENING THE CRANKSHAFT
Removal
1.
Almen gauge reading 0.012-A (0.305).
1.
2.
3.
4.
5.
6.
Remove lock ring and retaining washer
in
front of
crankshaft gear.
Pull off crankshaft gear. It has two 1/4-20 UNC
tapped holes for attaching a gear pulling ring.
Use care not to damage teeth if the gear is to be
reused. See Figure 61.
Remove oil pan, pistons and connecting rods.
Remove bearing cap from center main bearing.
Remove rear bearing plate from crankcase.
Remove crankshaft through rear opening
in
crankcase. Catch upper half of center main
bearing support as it slides off its mounting
surface.
Inspection:
Clean the crankshaft and blow out all oil
passages. Check journals for out-of-round, taper,
grooving or ridges. Pay particular attention to ridges
or grooveson eitherside of theoil holeareas. Unusual
conditions here often point to previous neglect of oil
changes.
If journal dimensions are not within limits, or the
journals are scored, regrind the crankshaft.
Crankshaft Grinding:
Crankshaft grinding requires a
trained, experienced operator working with precision
equipment. Procedures which may besatisfactoryfor
some spark-ignition engines may well be unsatisfac-
tory for diesel applications, resulting in expensive
failures. Onan emphasizes that if facilities or trained
personnel are not available, the crankshaft may be
sent to the factory.
Special procedures must be observed when rework-
ing diesel crankshafts.
In
addition to machining, the
crankshaft must be shot-peened and super-finished.
cause early failure. When the shaft is machined,
follow this data and Figure 62 to shotpeen each crank
pin fillet.
b
<
I
Failure to
shot-peen
the crankpin fillets is likely to
2. Peen with 0.019 inch (0.482 mm) diameter cast
3. Peen for 30 seconds on each crankpin fillet.
4. Mask off connecting rod bearing areas.
steel shot.
Undersize bearings and connecting rods are available
to rework the shaft to 0.010inch (0.254 mm),
0.020
inch
(0.508
mm), and 0.030 inch (0.762 mm) under-
size.
Main Bearings:
Replace main bearings if clearances
are greater than limits or if the bearings are worn,
grooved, or broken.
Precision replacement inserts and thrust washers are
available for all main bearings.
Do
not ream the.
bearings.
Align the oil holes and press the new bearings into the
front and rear housings. Insert the center bearing
when the crankshaft is reinstalled.
Rear
Oil
Seal:
The rear oil seal is in the rear bearing
plate. If damaged, drive
it
out from the inside of the
plate. Using the oil seal installing tool (Onan
No.
420-0250), install a new seal with the rubber lip facing
outward (open side of seal inward). See Figure 63.
Drive the new seal flush with the rear surface of the
bearing plate. Leave the seal installer on during bear-
ing plate installation to protect the oil seal.
'
Installation:
After each installation step, check the
crankshaft to be sure
it
is not frozen into place.
1.
Press front and rear main bearings into place,
align bearing and bearing housing oil holes.
Do
not attempt to drive a bearing into a cold block or
rear bearing plate.
2. Install thrust washers and locking pins.
3. Oil bearing surfaces and install crankshaft from
rear
of
crankcase through rear bearing plate hole.
57
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by any means, is strictly prohibited.
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