TM 5-3810-300-24&P-3
CAMSHAFT, BALANCE SHAFT AND BEARINGS 1.7.2
2. Leave a .010" to .030" radius between the bearing
surface of the thrust collar shoulder and the bearing
surface of the balance shaft (Fig. 7).
A fillet radius gage may be used to measure the
specified radii.
Examine the faces of the shaft end bearings and any
other surface which comes into contact with the thrust
washers. Parts that are badly marred must be replaced,
slight scratches may be cleaned up with an oil stone.
Inspect the bushings in the shaft end bearings. Replace
the bushings or end bearing assemblies if they are worn
excessively or the bushings have turned within the
bearing. New bushings must be finished bored to a 20
Fig. 7 - Camshaft and Balance Shaft Journal Fillets
r.m.s. finish after installation and tested for the correct
press fit. The correct press fit is indicated if the bushing
2. Apply grease to the steel face of each end thrust
does not move when a 2000 pound end load is applied.
washer. Then, place a thrust washer (6 and 27)
This test is of special importance with engines that
against each end of the camshaft and balance shaft
operate at high (2300 rpm) speeds. The inside diameter
rear bearings ("A" and "DI' engines). The steel faces
of the bushings must be square with the rear face of the
of the thrust washers must be towards the bearing.
bearing within .0015" total indicator reading, and
concentric with the outside diameter of the bearing
3. Lubricate the rear camshaft and balance shaft
retainer within .002" total indicator reading.
The
journals and slide the rear bearings on each shaft
bushings must project from .045" to .055" from each end
with the mounting flange of the bearing toward the
of the bearing.
gear end of the shaft.
The clearance between the camshaft and balance shaft
4. Install the gears on the shafts.
end journals and the end bearing bushings is .0025" to
.004" with new parts, or a maximum of .006" with used
5. Lubricate the camshaft intermediate bearing
parts. End bearings are available in .010" or .020"
journals. Then, place the two halves of each
undersize for use with shafts that are worn or have been
intermediate bearing on a camshaft journal and lock
reground and the clearances exceed the specified limits.
the halves together with the two lock rings. Install
each lock ring with the gap over the upper bearing
Replace excessively scored or worn camshaft
and the ends on equal distance above the split line
intermediate bearings. The clearance between the
of the bearing.
camshaft journals and the intermediate bearings is
.0025" to .005" with new parts, or a maximum of .009"
NOTE: Two intermediate bearing lock rings
with worn parts. Camshaft intermediate bearings are
are used. The current ring can be identified by
available in .010" and .020" undersize for use with worn
the wider gap. The wide gap ring MUST be
or reground shafts in which the clearances exceed the
used with the grooved type lower half bearings
specified limits. Examine the intermediate bearing lock
and can also be used with the former
screws and the tapped holes in the block. Damaged
intermediate bearings.
holes in the cylinder block may be plugged, redrilled and
tapped. Discard lock screws with damaged threads.
Install Camshaft and Balance Shaft
Assemble Camshaft and Balance Shaft
1. Insert the front end of the camshaft into the opening
on the blower side of the RA, and RC engines and
1. Install new end plugs in the camshaft.
on the opposite side of the RB and RD engines.
Push the camshaft into the cylinder block until the
camshaft gear teeth
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