Section VI. CRANKSHAFT & BEARINGS

TM 5-4110-217-14

Section VI. CRANKSHAFT & BEARINGS

5-24. General.

Removal of the camshaft or crankshaft bearings requires

complete disassembly of the engine. This would include

the removal of all accessories and assemblies covered

in previous removal paragraphs in Chapter 5, Sections I

thru V. This repair would also cover the inspection,

repair or replacement of the crankshaft, camshaft and oil

seals.

5-25. Crankshaft and Bearings.

a. Removal (fig. 3-11).

(1) Remove engine accessories and other

major assemblies and components described in

paragraph 5-1 thru 5-22

(2) Refer to paragraph 5-22 (3) for crankshaft

(199) removal. Remove crankshaft from crankcase at

end opposite flywheel end. Label piston parts to assure

proper reassembly.

(3) Use a press or a suitable drive plug to

remove crankshaft bearings (117A) and camshaft

bearings (209) from the crankcase (194) and bearing

Figure 5-25. Installation of Camshaft and Crankshaft

plate (117).

Bearings (Model RMP-J/I-l OG)

CAUTION

Support the casting to avoid distortion

lubricating hole (front only) in proper position. Be sure to

and avoid damaging the bearing bore

start the bearing straight. Press the front camshaft

during removal and installation.

bearing in flush with the outside end of the bearing bore.

(3) Press the rear camshaft bearing in until

b. Cleaning and Inspection.

past the ignition plunger hole.

(1) Clean all parts in approved cleaning

d. Installation of Crankshaft Bearings (fig. 5-25).

solvent. Blow out all oil passages. Dry parts thoroughly

(1) New crankshaft main bearings (117A) are

with clean, lint-free cloth.

precision type which do not require line reaming or line

(2) Inspect crankshaft, camshaft, bearings and

boring after installation

oil seals for cracks, chips, burrs, worn condition, and

CAUTION

other defects (3) Inspect crankshaft and camshaft

Support the casting to avoid distortion

bearing journals for scoring. Inspect the drilled passages

and avoid damaging the bearing bore

of the crankshaft for dirt or foreign material. Clean

during installation.

Use oil on the

passages to assure proper lubrication of the connecting

bearings to reduce friction when

rods.

installing and after installation.

(4) Remove crankshaft or camshaft burrs with

(2) Before putting in the main crankshaft

fine whetstone.

Replace or repair crankshaft or

bearings (117A), expand the bearing bore by

camshaft as necessary.

placing the casting in hot water or in an oven

(5) Replace defective bearings and oil seals.

heated to 200F. If practical, cool the precision

Refer to paragraph 1-5 tabulated data for tolerances and

bearing to shrink it.

clearances. Refer to paragraph 5-26 and 5-27 for oil

CAUTION

seal replacement.

If a torch is used, to prevent warpage,

c. Installation of Camshaft Bearings (fig. 5-25).

apply only a little heat.

(1) Replacement camshaft bearings are

precision type which do not require line reaming or line

(3) For putting in either the front or rear main

boring after installation. Coat the bearing with lubricating

bearing, always align the oil hole(s) in the bearing with

oil to reduce friction prior to assembly.

the oil hole(s) in the bearing bore. The oil passage must

(2) Place the camshaft bearing (209) on the

be at least 1/2 open. The cold oiled

crankcase (194) over the bearing bore with the

5-15