TM 5-3895-346-14
ENGINE OVERHAUL
CONNECTING ROD BEARINGS
CONNECTING ROD BEARINGS
The connecting rod bearing shells (Fig. 1) are
precision made and are replaceable without shim
adjustments. They consist of an upper bearing shell
seated in the connecting rod and a lower bearing
shell seated in the connecting rod cap. The bearing
shells are prevented from endwise or radial
movement by a tang at the parting line at one end of
each bearing shell.
The upper and lower connecting rod bearing shells
are different and are not interchangeable. The upper
bearing shell has two, short oil grooves and two oil
holes; each groove begins at the end of the bearing
shell and terminates at an oil hole. The lower
bearing shell has a continuous oil groove from one
end of the shell to the other. These grooves
maintain a continuous registry with the oil hole in the
crankshaft connecting rod journal, thereby providing
a constant supply of lubricating oil to the connecting
rod bearings, piston pin bushings, and spray nozzle
through the oil passage in the connecting rod.
The Brazilian-built engine, connecting rod bearings
include a slotted upper shell.
Remove Bearing Shells
The connecting rod bearing caps are numbered 1, 2,
3, etc. on an in-line engine with matching numbers
stamped on the connecting rods. When removed,
each bearing cap and the bearing shells must always
be reinstalled on the original connecting rod.
Figure 1. Connecting Rod and Bearing Shells
Remove the connecting rod bearings as follows:
1.
Drain the oil and remove the oil pan.
2.
Remove the oil inlet pipe and screen assembly.
3.
Remove one connecting rod bearing cap. Push the connecting rod and piston assembly up into the
cylinder liner far enough to permit removal of the upper bearing shell. Do not pound on the edge of
the bearing shell with a sharp tool.
4.
Inspect the upper and lower bearing shells as outlined under Inspection.
153
