not recommended as it could result in
very rapid bushing wear. A new piston
pin has a diameter of 1.4996" to 1.5000".
Replace the piston pin if it is worn to a
diameter of 1.4980" or less.
A s s e m b l e the Connecting Rod Piston
Refer to "Assemble Piston" on page
11B-73 for assembly of the connecting
rod to the piston.
CONNECTING ROD BEARINGS
Description
The
connecting
rod
bearing
shells
(Figure 11B-128) 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
F i g u r e 11B-128. Connecting Rod and
the connecting rod cap.
The bearing
shells are prevented from endwise or ra-
Bearing Shells
dial movement by a tang at the parting
line at one end of each bearing shell.
R e m o v e Bearing Shells
Various types of bearings have been
The connecting rod bearing caps are
used.
Currently,
multiple
layer
numbered 1, 2, 3, etc., with matching
copper-lead coplate or aluminum triplate
numbers
stamped on
the connecting
rods.
bearings are in use.
These bearings
When removed, each bearing cap
a n d the bearing shells must always be re-
have an inner surface called the matrix,
of copper-lead or aluminum. A t h i n d e -
installed on the original connecting rod.
position of babbitt is then plated onto
the matrix. This babbitt overlay has ex-
Remove the connecting rod bearings as
cellent resistance to friction, corrosion
follows:
and scoring tendencies which, combined
with the materials of the matrix, pro-
1 . Drain the oil and remove the oil pan.
vides
improved
load
carrying
characteristics.
These
bearings
2. Remove the lubricating oil pump and
are
identified by the satin silver sheen of
pump inlet and outlet pipes.
the babbitt when new and a dull gray af-
ter being in service.
NOTE
The upper and lower connecting rod
If shims are used between the oil
bearing shells are different and are not
pump body and the main bearing
interchangeable.
The upper bearing
caps, save the shims so they may
shell is grooved midway between the
be reinstalled when installing the
bearing edges, part way up from each
oil pump.
parting line, with an oil hole through the
shell at the termination of each groove.
3. Remove one connecting rod bearing
The lower bearing shell has a continuous
cap.
Push the piston and rod assembly
registry with the oil hole in the crank-
up into the cylinder liner far enough to
shaft connecting rod journal, thereby
providing a constant supply of lubricat-
permit r e m o v a l o f t h e u p p e r bearing
shell.
ing oil to the connecting rod bearings,
Do not pound on the edge of the
bearing shell with a sharp tool.
piston pin bushings and spray nozzle
through the oil passage in the connecting
rod.
E n g i n e (Less Major Assemblies)
