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 TM 55-1925-204-12
b. Camshaft Bearing Replacement. The camshaft
procedure used in step (3) above to assemble the motor.
(7) Reassembly of pump.
Reverse the
sleeve bearing assemblies are in halves (lower in box,
upper in cap), and come in three sizes depending on
procedure used in step (2) above to assemble the pump.
location. Shims are used for adjustment of clearance
(8) Installation. Reverse the procedures used
after bearings are hand scraped and fitted. Replace
in step (1) above to install the pump assembly on its
bearing (s) as follows:
mount and connect to the oil system.
(1) Preparation.
(a) Remove the capscrews securing
4-17. Camshaft and Timing System
the camshaft cover to the camshaft lower housing located
a. General. The diesel engine camshaft is driven by
at right of the astern/ahead handwheel. Lift off the cover.
the crankshaft, through a gear train located at aft (drive)
(b) Remove nuts securing the inspection
end. The camshaft is supported by four camshaft
plate located to left of the astern/ahead handwheel. Lift
bearings and an end bearing at the drive end. Camshaft
off the inspection plate.
bearings are stamped with placement markings so they
(2) Bearing removal.
may be returned to their original position.
(a) Remove capscrews securing bearing
NOTE
cap (3, fig. 4-15) and bearing box (5).
If
bearing
replacement
becomes
necessary, these markings should be
carefully transferred to the new
bearings.
1.
Cover
6.
Camshaft
2.
Gasket
7.
Gasket
3.
Bearing cap
8.
Gasket
4.
Shims
9.
Rim
5.
Bearing box
10.
Nuts
Figure 4-15. Camshaft and bearings.
(b) Remove bearing cap (3), shims (4),
(4) Installation.
and bearing box (5).
Tag and identify shims for
(a) Position bearing box under camshaft.
reinstallation. Check one bearing at a time, until the five
Lay shims on bearing box and remove tags.
are completed.
(b) Install bearing cap and secure with
(3) Cleaning, inspection, and repair.
the capscrews. Tighten screws evenly.
(a) Wash bearing halves in clean fuel oil
(5) Adjustment.
and wipe dry.
(a) Place leaf is) of thickness gage 0.125
(b) Inspect bearing surfaces for cracks,
in. wide on camshaft and slide under bearing cap and
discoloration from overheating, or other defects. Replace
find clearance.
a defective bearing assembly when either half is
(b) If clearance is between 0.001 and
defective.
0.0065 in. the adjustment is correct.
(c) If a defective bearing is replaced,
(c) If clearance is 0.001 in. or less,
scrape and fit in a manner similar to that described for
change shim stack on both sides as follows:
main bearings in paragraph 3-23.
4-27
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