SEC. 1.3 Page 5
TM 5-3810-300-24&P-3
1.3 Crankshaft
Nominal
Thickness
Cool the crankshaft while grinding, using coolant
Size
generously. Do not crowd the grinding wheel
Min.
Max.
into the work.
Standard
.1190"
.1220"
5. Polish the ground surfaces to an 8-12 R.M.S.
.005" Oversize
.1255"
.1270"
finish. The reground journals will be subject to
.010" Oversize
.1300"
.1320"
excessive wear unless polished smooth.
TABLE 3
6. If the thrust surfaces of the crankshaft (Fig. 8)
are worn or grooved excessively, they must be
main bearing cap. The grooved side of the
reground and polished. Care must be taken to
thrust washers must face toward the crankshaft
leave a .130" to .160" radius between each
thrust surfaces.
thrust surface and the bearing journal.
7. Stone the edge of all oil holes in the journal
NOTE: If the crankshaft thrust surfaces
surfaces smooth to provide a radius of ≈3/32".
were reground, it may be necessary to
install oversize thrust washers on one or
8. After grinding is completed, inspect crankshaft
both sides of the rear main journal.
by the magnetic particle method to see if cracks
Refer to Fig. 8 and Table 3.
have originated due to the grinding operation.
5. Install the lower bearing shells (no oil grooves) in
9. De-magnetize the crankshaft.
the bearing caps. If the old bearing shells are to
be used again, install them in the same bearing
10. Remove the plugs and clean the crankshaft and
caps from which they were removed.
oil passages thoroughly with fuel oil. Dry the
shaft with compressed air and reinstall the plugs.
6. Install the bearing caps and lower bearing shells
as outlined under Install Main Bearing Shells in
Install Crankshaft
Section 1.3.4.
If a new crankshaft is to be installed, steam clean it to
remove the rust preventive, blow out the oil passages
NOTE:
If the bearings have been
with compressed air and install the plugs. Then install
installed properly, the crankshaft will turn
the crankshaft as follows:
freely with all of the main bearing cap
bolts drawn to the specified torque.
1. Assemble the crankshaft timing gear (Section
1.7.5) and the oil pump drive gear (Section 4.1)
7. Check the crankshaft end play by moving the
on the crankshaft.
crankshaft toward the gage (Fig. 9) with a pry
bar. Keep a constant pressure on the pry bar
2. Refer to Section 1.3.4 for main bearing details
and install the upper grooved main bearing
shells in the block. If the old bearing shells are
to be used again, install them in the same
locations from which they were removed.
NOTE: When a new or reground crankshaft
is installed, ALL new main and connecting
rod (upper and lower) bearing shells and
new thrust washers must also be installed.
3. Apply clean engine oil to all crankshaft journals
and install the crankshaft in place so that the
timing marks on the crankshaft timing gear and
the idler gear match. Refer to Section 1.7.1 for
the correct method of timing the gear train.
4. Install the upper halves of the crankshaft thrust
washers on each side of the rear main bearing
Fig. 9. Checking Crankshaft End Play
support and the doweled lower halves on each
side of the rear
Thrust Washer
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