Figure 6-42. Oil Pan Gaskets and Seal.

TM 10-3930-633-34

A VS. B = VERTICAL TAPER

C VS. D = HORIZONTAL TAPER

A VS. C AND B VS. D = OUT OF ROUND

Figure 6-42. Oil Pan Gaskets and Seal.

6-30. Crankshaft Cleaning and Inspection

Figure 6-43. Journal Measurements.

a. Cleaning.

(3) Inspect the rear oil seal surface of the

(1) Clean the crankshaft by rinsing in a bath

crankshaft for excessively deep grooves, nicks,

of solvent, Federal Specification P-D-680. Blow

burrs, porosity, or scratches which could damage

out all oil passages with compressed air.

the oil seal lip during installation. Remove all

NOTE

nicks and burrs and polish the chamfered edge

Handle the crankshaft very carefully to avoid

and oil seal contact surface wit h crocus cloth.

possible fractures or damage to the finished bearing

(4) Inspect the crankshaft damper or sleeve

surfaces.

oil seal surface for nicks, sharp edges or burrs

(2) Clean the oil seal surface at the rear of the

that might damage the oil seal during installation

crankshaft with solvent to remove any corrosion,

or cause premature seal wear.

sludge or varnish deposits. Excessive deposits

not readily removed with solvent may be removed

6-31. Connecting Rods Cleaning and Inspection

with crocus cloth.

a. Cleaning. Remove the bearings from the rod

(3) Use crocus cloth to remove any sharp

and cap. Identify the bearings if they are to be

edges, burrs or other imperfections which might

used again. Clean the connecting rod in solvent,

damage the oil seal during installation or cause

including the rod bore and the back of the inserts.

premature seal wear.

Do not use a caustic cleaning solution. Blow out

CAUTION

all passages with compressed air.

Do not use crocus cloth to the extent that

b. Inspection.

the seal surfaces become polished. A

(1) The connecting rods and related parts

finely polished surface may produce poor

should be carefully inspected and checked for

sealing or cause premature seal wear.

conformance to specifications. Various forms of

(4) Clean the oil seal contact surface on the

engine wear caused by these parts can be readily

crankshaft damper or sleeve with solvent to

identified.

remove any corrosion, sludge or varnish deposits.

(2) A shiny surface on the pin boss side of

Excess deposits that are not readily removed with

the piston usually indicates that a connecting rod

solvent may be removed with crocus cloth.

is bent or the piston pin hole is not in proper

b. Inspection.

relation to the piston skirt and ring grooves.

(1) Inspect the main and connecting rod

(3) Abnormal connecting rod bearing wear

journals for cracks, scratches, grooves or scores.

can be caused by either a bent connecting rod, an

(2) Measure the diameter of each journal at

improperly machined journal, or a tapered

least four places to determine out-of-round, taper

connecting rod bore.

or undersize condition (fig. 6-43). Refer to table 6-

(4) Twisted connecting rods will not create

6 for specifications.

an easily identifiable wear pattern, but badly

6-32