Figure 3-9. Piston and ring assembly.

*TM 9-2815-213-34

Figure 3-10. Connecting rod check.

not exceed wear limits shown in repair an build

standards in paragraph 3-178. f. Check connecting rod

B28) into connecting rod bore. Tighten mandrel to snug

piston pin and bearing bore alignment, rod twist, and

fit.

rod centerline (fig. 3-10) in rod checking fixture (40, fig.

(2) Install mandrel (22, fig. B-28) used without

B-28). Calibrate fixture, before checking rod, as foil (1)

bushing or (21, fig. B-28) used with bushing into piston

Select a new rod that has been checked for correct

pin bushing bore.

absolute length. (Production rods vary from 8.192/8.194

(3) Install rod with mandrels in fixture Note

inches in length.)

reading, rotate rod 180 degrees, and note reading

(2) Assemble cap to rod and tighten nuts to

again. Total cumulative readings of each dial on fixture

proper torque (para. 3-186).

must not exceed 0.004 inch with piston pin bushing

(3) Insert mandrel (22, fig. B-28) without

installed or 0.008 inch with-out piston pin bushing

bushing or (21, fig. B-28) used bushing into piston pin

installed.

bushing bore.

h. Check rod twist with a feeler gage between

(4) Insert mandrel (20, fig. B-28) crankpin

piston pin mandrel and dial holding plate. Twist must not

bushing bore. Tighten mandrel in to snug fit.

exceed 0.010-inch with bushing installed or 0.020-inch

(5) Position rod with mandrels installed into

without bushing.

fixture (40, fig. B-28).

i. Check rod centerline as follows:

(6) Move dial holders so dial pins seat on

(1) Attach dial indicator gage to fixture (fig. 3-

piston pin bore mandrel. Turn dial indicator gages back

10) so that it will contact the milled surface of piston pin

to zero indication.

end of rod.

(7) Remove rod with mandrels installed from

(2) Slide crankpin end of rod sideways to

fixture, rotate rod 180 degrees and reinstall in fixture

contact checking fixture on same side that dial indicator

with connecting rod mandrel at top.

is mounted.

(8) Turn dial indicator adjusting screws until

(3) Adjust indicator gage to zero reading. Turn

dial pins seat on connecting rod mandrels. Note reading

Rod 180 degrees and repeat step (2) above. Dial

of dial indicators. Divide reading in half and adjust each

indicator reading must not exceed 0.015 inch.

dial indicator gage accordingly.

j. Check connecting rod bolts, bolt holes, and bolt

(9) Remove mandrels from connecting bores.

pads as follows:

g. Check rod alignment as follows:

(1) Bolt head must rest squarely on milled

surfaces of rod.

NOTE

(2) With rod bolt in connecting rod and cap,

measure bolt length without torque applied,

then

Measurements taken directly from dial

measure bolt length with it torqued to 105/115 ft lbs. If

indicator indicate comparative length

bolt length increases over 0.015 inch it must be

and misalignment of bores.

discarded.

(3) Discard all bolts and nuts that have

(1)

Install connecting rod mandrel (20,fig

distorted threads.

(4) Check bolt hole diameter, if it exceeds

0.5643 inch, discard rod.

3-6