TM 5-6115-400-35
2.0027
inches-2.0033
inches.
(c) Lubricate and install a bearing shell
These dimensions of pin and
in position in the connecting rod
bushing provide a clearance of .001
bearing cap, with tang of bearing
inch-.0018 inch; clearance up to
shell in corresponding slot in
.003 inch is permissible.
If
bearing cap. Install bearing cap and
clearance is close to or beyond .003
shell, making certain identification
inch, replace the connecting rod
number stamped in the bearing cap
bushing.
is located on the same side as
corresponding number stamped in
(d) Blow dry compressed air through
the connecting rod.
the oil passage in connecting rod.
(d) Install the connecting rod nuts and
Note.
tighten to the specified torque.
Be sure that all oil passages are
open.
(e) Check to see that there is sufficient
(e) Inspect connecting rod bearing
clearance between connecting rods
and crankshaft journals.
The
shells
for
scoring,
chipping,
specified clearance is .004 inch-
corrosion, cracking, or signs of
.009 inch.
overheating; discard bearing shells
if any of these conditions are
c. Connecting Rods and Connecting Rod Bearings.
apparent. The backs of bearing
(1) Inspection.
shells should be inspected for bright
(a) Clean connecting rod so it is free
spots and discarded if any bright
from oil and other matter. Check
spots are found; this condition
connecting rod for cracks by the
indicates that bearing shells have
magnetic
particle
method.
been moving in their supports.
Magnetize the connecting rod and
(f) Inspect bearing shells for wear. The
cover it with a fine magnetic powder
specified inside diameter of bearing
or solution. Cracks will form a small
shells
is 3.3756 inches-3.771
local magnet which causes the
inches, when installed and bearing
magnetic particles in the powder or
cap retaining locking type nuts
solution to gather there, marking the
tightened to the specified torque of
cracks. If any cracks are detected,
175 to 185 ft. lbs.
or when
the connecting rod must be
castellated nuts tightened to a
replaced.
torque of 160 to 170 ft. lbs. This
(b) Whenever connecting rods are
provides a running clearance of
removed from an engine it is good
.0021 inch-.0046 inch; new bearing
practice to check alinement of the
shells must be installed when this
piston pin bushing end with the
clearance exceeds .009 inch.
large bore end. Alinement can be
(g) Measure rod bearing shells for
checked with a direct reading
wear; connecting rod bearings have
alinement gage similar to the one
a specified thickness of .12395
shown in figure 94. Note that with
inch-.12445 inch; bearing shells that
this type alinement gage the rod
measure less than .1225 inch at the
can be checked with or without the
center should be discarded and new
piston assembled to it.
ones installed.
(c) Measure outside diameter of the
(h) In the event that the crankshaft is
piston pin to determine wear. The
worn or damaged and must be
specified diameter of a new piston
ground, bearing shells .010 inch,
pin is 2.0015 inches-2.0017 inches.
.020 inch, .030 inch, and .040 inch
The specified inside diameter of the
undersize are available.
bushing in the connecting rod is
127
