Paragraphs
94-96
Fig. AC3B'-Models WC, WD
and
WF iron
piston, liner
and
connecting
rod
assembly.
Pistons 1 and
3
have long
pin
boss toward
timing gears, and pistons
2
and
4
have
the
long
pin
boss toward
the
flywheel. Piston
pins
are of the
locked-in
rod
type,
1. Pin bushing, short 6, Piston pin lock
2.
Pin bushing, ion, 7. L^|Larin»
8. Plain compression g. Bearing shims (Not
rings used on WD45 aft-
4.
Scraper compression er W45FG1001)
ring 9. Seal rings
5.
Ventilated oil ring 10. Cylinder liner
number
one and
three units
so
that
the
rod (A) is
nearest the rear pin boss
with
end of pin
slightly less than flush
with same face
of
piston,
as
shown
in
Fig. AC37.
Assemble number
two and
four
units
in the
opposite arrangement
as
shown.
IRON PISTONS—WC-WD-WF.
As-
semble pistons
to
connecting rods
so
that numbers
1 and 3
have
the
longer
boss
of the
piston toward
the
timing
gears
and
numbers
3 and 4
have
the
longer boss toward
the
flywheel. Refer
to Fig. AC38.
Model
G
94.
The
uncored (solid) .S434 diam-
eter floating piston pins are retained
in
the piston bosses
by
snap rings
and
are available
in
standard
and
over-
sizes
of
.003
and
,00S.
The
bushing
in
the upper
end of
connecting
rod has
a very thin wall
and if
sized
by
ream-
ing,
do so
only with
a
special fluted
type
and
take very light cuts.
Be
sure
oil hole
in
bushing registers with
oil
hole
in top end of the
connecting
rod
and
be
sure
to
clean same thoroughly
after sizing
the
bushing.
Pin
should
be
fitted to
a
finger push
fit
(.0003 clear-
ance)
in the rod, and a
thumb push
fit
in
the
piston.
Assemble pistons
to
rods
to
place
split
in
aluminum piston
on
side oppo-
site
the
camshaft.
CONNECTING RODS AND
BEARINGS
All Except Model G (Shimmed
Type)
95.
Connecting rod bearings used
in
models
B, C,
CA, RC, WC, WD, WD45
prior engine serial W45FG1001
are of
the slip-in type, provided with shims
for
a
limited range
of
adjustment
and
are renewable from below.
When installing
new
bearing shells,
be sure that
the
projection engages
milled slot
in
rod and cap. Replacement
rods
are not
marked
and
should
be in-
stalled with the piston pin clamp screw
facing the camshaft.
Bearings are available
in
,0025, ,005,
.040,
.0425 and .45 undersize as well
as
standard
for
service
B-C
WC
CA
WD
WD45
RC
WF
Crankpin diameter
(mean)
1,937
2,3745
WC (prior
to
#3665)
1.9995
Running clearance
(shimmed)
1-2 1-3
Side Clearance
4-7 5-8
Bolt Torque (ft.-lbs.)
. . 35 *
Castellated
with cotter pin
35 70
Self locking
35 40
•Tighten castellated connecting
rod
nuts
to
70 ft-lbs. torque
and
secure with
a
cotter
pin.
On
self-locking ("lug
lock")
nuts, torque nuts to
40 ft-lbs.
BEARING ADJUSTMENT.
Con-
necting
rod
bearing shims which
are
provided
for a
limited range
of ad-
justment
do not flt
between
the
bear-
ing shell parting surfaces,
but
only
between
the
bearing
cap and its mat-
ing surface,
as
shown
in Fig.
AC40.
These shims control
the
amount
of
crush
or
pinch placed
on the
shell
and
only indirectly control
the
bearing
running clearance
of
0.001-0.003,
Individual shim thickness
of the
factory supplied shim pack
of
four
shims
is
0.002S. Although Allis-Chal-
mers approves
the
removal
of as
many
as two shims from each side
as a
means
of reducing
the
running clearance,
it
is considered
a
better practice
to in-
stall new undersize shells
if
new stand-
ard size shells do
not
restore
the
clear-
ance
to the
recommended values.
In
an
emergency where
new
bear-
ings
are not
available,
the
desired
clearance
can be
obtained
by
reducing
the height
of the
bearing shells.
For
each .002 reduction
in
height
of a
pair
of shell inserts, remove
a
,002S shim
from each side. Removal
of
metal from
the parting surface
of
shell (reducing)
can
be
accomplished with fine emery
paper
and a
fiat surface, making
an
ALLIS-CHALMERS
occasional check
on the
bearing shell
height
to
prevent removal
of
too much
metal.
For
new
bearing shells
and
crank-
shaft installation,
use the
standard
shim pack
of
four 0.002S shims which
will automatically provide
the
correct
running clearance
of
0,001-0.003
and
the correct bearing crush
of
O.OOIS.
Models WD-WD45 (Shimless Type)
9SA. Connecting
rod
bearings used
in WD4S tractors equipped with
en-
gines after serial W4SFG1001
are of
the shimless, non-adjustable, slip-in,
precision type
and are
renewable from
below after removing
the oil pan and
bearing caps.
Shimless type connecting
rod
bear-
ings
can be
used
in all
WD
and
WD45
tractors
if the
shimless type connect-
ing rods
are
used also.
When installing
new
bearing shells
be sure that
the
projection engages
the milled slot
in
both
the rod and
cap.
Replacement rods
are not
marked
and should
be
installed with
the
piston
pin clamp screw facing
the
camshaft.
Bearings
are
available
in
.002S, .OOS,
,040,
.042S,
and
.04S undersize
as
well
as standard.
Crankpin diameter (mean) 2.374S
Running clearance, shimless...,
1-3
Side clearance
5-8
Bolt torque (ft-lbs,)
*
Castellated with cotter
pin 70
Self locking
40
•Tighten castellated connecting
rod
nuts
to
70 ft-lbs. torque and secure with
a
cotter pin.
On self-locking ("lug
lock")
nuts, torque nuts
to 40 ft-lbs.
Model
G
96.
Connecting
rod
bearings
are
shimless, non-adjustable, slip-in,
pre-
cision type, renewable after removing
the
oil pan and
bearing caps. When
installing
new
bearing shells,
be
sure
that
the
projection engages milled
slot
in rod and cap.
Bearings
are
available
in .002 and .020
undersize,
as well
as
standard.
Fig, AC39-Model
G
aluminum piston*
are
correctly fitted when 10-15 pounds pull
Is
required
to
withdraw
the .0015
feeler
gage.
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