Figure 6-10. Checking torque of main bearing cap studs.

their

original

location

crankcase

and

main

not cause for rejection. Pitting or any other form

bearing caps.

of destruction to the bearing surface is cause for

(d) Check clearance between upper

rejection. Replace bearings showing raised metal

bearing flange and crankcase as shown in figure

at edges of scratches.

6-11.

(d) Minute pieces of metal and dirt

(e) Check clearance between the lower

particles embedded in bearing surfaces are not

main thrust bearing flange and thrust bearing

cause for rejection.

cap in the same manner as shown in figure 6-11.

Note. Do not attempt to remove such

particles. However, if a concentration of em-

bedded particles affects five percent of the

surface,

replace

the

bearing.

(4) Stud (tie rod) torque and main bearing

bore inspection.

Note. Main sleeve bearing halves should be

installed in their original location when they are

to be re-used. Use new bearings when a visual

inspection indicates bearings are unserviceable.

Use only new or serviceable bearings for main

bearing-bore check.

(a) Refer to figure 6-8 for instructions to

install crankcase on engine overhaul stand.

(b) Check main bearing cap stud torque

using a torque wrench as shown in figure 6-10.

Torque on studs must be 450 pound-inches.

Studs that do not tighten to specified torque

must be removed for further inspection. Refer to

table

6-3

when

replacing

studs.

Note. Never tighten main bearing studs

above

recommended torque.

1. Install upper main thrust sleeve bearing (A) into No.

4 main bearing seat of crankcase.

2. Measure clearance between bearing flange and crank-

case using feeler gage (B). Clearance should be 0.0040

to 0.0080-inch.

Figure

6-11.

Checking

clearance

between

upper main thrust bearing

flange and crankcase.

(f) Apply a light coating of engine oil,

Military Specification MIL-L-45199, to the ends

the

seven

main

bearing

caps

with

sleeve

bearing

halves

installed. Using crankcase

spreading tool - 5120-575-7767 as shown in

Figure 6-10. Checking torque of main

figure 5-174 install the bearing caps with bearing

bearing cap studs.

halves in their proper locations in the crankcase.

according to the location number stamped on the

crankcase and cap. The side of the bearing cap

FSN 8010-247-8706, over steel backs of upper

marked "FLY END" must face the rear of the

and lower main sleeve bearing halves to show the

crankcase.

sleeve

bearing

contact

surface

with

the

main

(g) Apply

small

amount

antiseize

bearing bore in crankcase. Install bearings in

6-16