REPAIR INSTRUCTIONS
Page 173
CONNECTING ROD AND
PISTON BENCH PROCEDURES
Connecting Rod Inspection and
Reconditioning
[212 LP]
GENERAL INSTRUCTIONS
The connecting rod and cap design incorporates
alignment sleeves. The caps can be identified by
the flat, machined bottom shown in Figure 164.
The connecting rod part number is forged into the
I-beam of the rod.
164
Figure 164 — Connecting Rod Identification
Refer to Figure 165.
Each connecting rod assembly has two alignment
sleeves (3), one sleeve in each capscrew hole of
the rod cap (1) to locate and align the cap and rod
thrust faces. These sleeves provide the best
alignment when sleeve gaps are positioned at a
location approximately 90 degrees to the tongue
or groove (2). The sleeve gaps must not be in line
with the tongue or groove.
165
Figure 165 — Connecting Rod with Alignment Sleeves
It is essential to closely control the weight of
reciprocating parts. Connecting rods fall into two
weight classes, M1 or M2. Initially, the classes
were identified by the respective “M” number
(M1 or M2) stamped onto the connecting rod
bearing cap. Now, however, only the M1 rod
carries the weight class identification stamped on
the rod cap. The M2 connecting rod is no longer
stamped with the weight class identifier.
When installing a single rod, or less than a full
set, examine the removed rod for part number
and M number. Installing parts with the same
weight class is preferred.
Connecting rods can be weighed to ensure using
the proper weight class. Connecting rod weights
for each engine, within each weight class, should
not vary by more than 0.46 ounce (13.04 grams).
The maximum weight difference between the
heaviest possible M2 rod and the lightest
possible M1 rod is 0.83 ounce (23.53 grams).
1. Connecting Rod
2. Rod Cap Machined
Surface
1. Rod Cap
2. Bearing Insert
3. Alignment Sleeve
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