Connecting Rod Bearings - TM-55-1925-204-120133

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Figure 3-6. Piston, connecting rod, and rings.

TM-55-1925-204-12 TUG Harbor Diesel 1200 H. P. Steel 100 Ft Design 3006 Flight One FSN 1925-375-3003 Manual

Figure 3-7. Connecting rod bearing.

KEY to fig. 3-6:

NOTE

The connecting rod bearing box can

Rings

9. Nut

be left on the crankshaft journal. If

Bracket

10. Shims

this is a complete disassembly,

Pin. dowel

11. Rod

remove bearing box as described in

Bearing

12. Stud dowel

c. below.

13. Nut

(16) Move piston and connecting rod to a clear

Bracket

14. Cap

working area and place it in a wood cradle. Position it so that

Pipe, telescopic

15. Pin, dowel

weight of connecting rod will not overbalance the piston.

(17) Remove piston pin brackets and caps (6 and

Bolt

14) on both sides of piston.

Tag the caps (14) for

reinstallation identification.

(7)

Tag the nuts and bolts for reinstallation

(18) Remove the telescopic pipe (7). Remove nuts

identification.

(13) from studs (12), then remove piston pin (5). Wrap pin in

(8)

Make a punchmark on foot of connecting rod

a clean cloth to prevent damage then lay it in a protected

and the gearing box to assure placement at installation.

area.

CAUTION

NOTE

The foot of the connecting rod will

Before removing the connecting rod

score the wall of the cylinder unless

from piston, place an identifying

guides are used.

punchmark on rod and piston to

(9)

Clamp the connecting rod guides

assure reassembly is same relative

(table 41) to foot of the connecting rod.

position. Do not reverse the rods

(10) Hoist piston until foot is clear of the bearing

box, then remove shims (10). Tag the shims for proper

position in the piston.

installation identification.

(19) Withdraw the rod (11) from the piston and

(11) Hoist the piston until the five ring grooves are

store in a protected area.

above the cylinder head studs, then check all rings for

c. Connecting Rod Bearings.

freedom of movement. Stuck rings may be loosened by

NOTE

tapping lightly with a lead or plastic hammer. If rings are too

These bearings can be replaced

solid for this method of loosening, they must be removed after

without removing cylinder head and

the piston has been placed in a cradle.

piston.

Proceed as follows: (1)

(12) Remove piston rings (1) by using three thin

Remove the appropriate crankcase

strips of steel (old hacksaw blades will serve) placed at equal

distance around the piston and under the rings. Do not

inspection plate from both sides of

spread the rings any more than is necessary to remove them.

the engine.

Removing rings at this time makes piston less difficult to

(2)

Use the flywheel ratcheting device to turn

handle.

engine over until the desired piston is at top dead center.

(13) Tag all rings to indicate the groove and piston

(3)

Install the two piston clamps (table 4-1) on

from which removed for replacement identification. After

lower end of cylinder wall with capscrews provided. Be sure

inspection some rings may be re-used.

the other end of clamps project upward into the cylinder bore.

(14) Hoist the piston and rod clear of the cylinder,

(4)

Remove cotterpins and nuts (3, fig. 3-7) from

then remove the connecting rod guides.

the two bolts (2), then remove the two bolts (2).

(15) Position two tapered wooden blocks inside

piston to block the connecting rod so that it will not

damage piston while it is being moved to a clear

working area.

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