10
Beginning with car Serial No. 491-52515 a
third type connecting rod (forging No. 302601) is
used. In this type rod the "I" beam section has been
changed. The center raised section has been re-
moved and a full "I" section adopted.
Provision for lubricating the cylinder walls
through a drilled hole to connecting rod bearing is
retained in the non-rifle drilled connecting rods.
All three types of rods are interchangeable with
each other, however they must be selected for uni-
formity of weight and a set of 6 rods must not vary
1/4 oz.
NOTE: It is permissible that the non-drilled rods be
a 1/8 of ounce heavier as this will be compensated for
by the oil weight in the rifle bore connecting rods
.
CONNECTING ROD AND PISTON ASSEMBLY
(6 CYLINDER)
Connecting rods and pistons must be assembled
with the oil hole in the connecting rod on the oppo-
site side of the slot in the piston, see Figure 10.
FIGURE 10
Piston and connecting rod assembly must be
installed in engine with the connecting rod oil spurt
hole toward the valve side of the engine.
VIBRATION DAMPENER - PAGE 3-30
Vibration dampener Part No. 300098 was used on
all the 480 models and on 490 series up to June 13,
1949. Part 300098 was superseded by Part No.
301934. This later type dampener has the front face
machined at an angle to facilitate the drilling opera-
tion on the factory special balancing machine.
Six cylinder engines that have been balanced on
the special balancing machine may be identified by
a letter "B" stamped on the front machined face of
the cylinder block beside the water pump housing.
These dampeners may or may not be drilled as
indicated in the cut below but are in proper balance
with the crankshaft of the engine on which it was
installed.
The center punch marks, one on the front end of
hub, another opposite it on the pulley; Figure 11.
These punch marks indicate the relative position of
the inner and outer members when assembled and
balanced and may also serve as a guide to the me-
chanic for proper assembling.
FIGURE 11
NOTE: Whenever it is found necessary to replace
a crankshaft of one of these special balanced
engines, always use the later type vibration
dampener Part No. 301934.
VIBRATION DAMPENER - NOISE
The inner member or hub of the vibration damp-
ener is secured to the crankshaft with a key and cap
screw. The outer member is attached to the hub by
means of two rubber discs, a plate and cap screws,
Figure 11.
