ALLIS-CHALMERS
an undersize gear. The enclosed num-
ber gives the deviation from a standard
size gear in thousandths of an inch.
When installing new gears, always use
the same size gears as were removed
and check the backlash to make cer-
tain that the value is within the clear-
ance limits. Due allowance should be
made, however, for wear on the other
gear if only one gear is renewed.
Usually, new gears are punched
with timing marks before they leave
the factory. If, however, a new gear
is not so marked, it is important to
transfer the marks from the old gear
to the new. To do so, proceed as fol-
lows:
Place the old gear on top of the
new one and using a piece of key-
stock, align the key ways of both
gears.
Place a straight edge against
the gear teeth and in line with the
timing mark on the old gear. Locate
and punch mark the appropriate tooth
(or tooth space) on the new gear.
Refer to Fig. AC58.
To facilitate installation of a new
crankshaft gear, boil the gear in oil
for a period of 15 minutes prior to in-
stallation. When installing the cam-
shaft gear, mesh the single punch
marked camshaft gear tooth space
with the single punch marked crank-
shaft gear tooth as shown in Fig.
AC56.
NOTE: When installing the camshaft gear
with the camshaft in the engine, remove
the oil pan and place a heavy bar against
the side of a cam to hold the camshaft in a
forward position while the gear is being
drifted on. This procedure will eliminate the
possibility of loosening the soft plug which is
located in the cylinder block at the rear of
the camshaft.
CAMSHAFT AND BEARINGS
The camshaft is supported in four preci-
sion steel-backed, babbitt-lined bearings. The
shaft journals have a normal operating clear
ance of 0.002-0.0046 in the bearings- If the
journal clearance exceeds 0.014 the bear-
ings and/or shaft should be renewed. To
renew the bearings, follow the procedure
outlined in paragraph 144A. To renew the
camshaft, refer to the following paragraph.
144.
CAMSHAFT. To remove the
camshaft, first remove the crankcase
front cover as outlined in paragraph
143B,
then, proceed as follows: Remove
valve cover, rocker arms assembly
and push rods. Insert long wooden
dowel pins down through the push
rod openings in crankcase and tap
the dowels into the tappets (cam fol-
lowers). Lift dowels up, thereby hold-
ing tappets away from camshaft and
hold dowels in the raised position
with spring type clothes pins. Re-
move oil pan and oil pump. Working
through openings in camshaft gear,
remove the camshaft thrust plate re-
taining cap screws and withdraw cam-
shaft from engine.
Recommended camshaft end play
should be 0.003-0.008. Refer to timing
gears (paragraph 143C) for the
method of checking and adjusting the
camshaft end play.
Check the camshaft against the
values which follow:
No.
1 (front) journal
diameter
1.998-1.999
No.
2 journal diameter.,.. ,1.998-1.999
No.
3 journal diameter
1.998-1,999
No.
4 (rear) journal
diameter
1.248-1.249
When installing the camshaft, re-
verse the removal procedure and make
certain that the valve timing marks
are in register as shown in Fig, AC56.
Caution: Make certain that the drilled
camshaft thrust plate retaining cap
screw is installed in the lower hole.
144A. CAMSHAFT BEARINGS. To
remove the camshaft bearings, first
remove the engine as in paragraph
141;
then, remove camshaft as in the
preceding paragraph 144, Remove
clutch, flywheel and the engine rear
end plate. Extract the soft plug from
behind the camshaft rear bearing and
remove the bearings.
An approved method for removing
the bearings is to split the bearings
with a hack saw blade and drive the
bearings out with a chisel. Exercise
special care during this operation,
however, to avoid damaging the
crankcase bearing bores. Clean the
camshaft bearing oil holes in crank-
case.
Paragraphs 144-144C
Using a closely piloted arbor, in-
stall the bearings so that oil hole in
bearings is in register with oil holes
in the crankcase.
The inside diameter of the cam-
shaft bearings after installation should
be as follows:
No.
1 (front) 2,0010-2.0026
No.
2 2.0010-2.0026
No,
3 2,0010-2.0026
No,
4 (rear) 1.2510-1.2526
Although the camshaft bearings are
presized, it is highly recommended
that the bearings be checked after in-
stallation for localized high spots. The
camshaft bearing journals should have
a normal operating clearance in the
bearings of 0.002-0.0046.
When installing the soft plug at
rear camshaft bearing, use Permatex
or equivalent to obtain a better seal.
CONNECTING ROD AND
PISTON UNITS
144B.
Piston and connecting rod
units are removed from above after
removing cylinder head and oil pan.
The procedure for removing the cylin-
der head is outlined in paragraph 142.
Cylinder numbers are stamped on
the connecting rod and the cap. When
reinstalling the rod and piston units,
make certain the cylinder identifying
numbers are in register and face op-
posite the camshaft side of engine.
Tighten the connecting rod bolts to
a torque of 30 to 40 ft. lbs.
PISTONS, RINGS AND SLEEVES
144C.
Each piston is fitted with five
rings;
three Vs-inch wide compression
rings and two ^-inch wide oil con-
Key
Fig.
AC58—In rare cases,
replacement timing gears
are not punched witK tim-
ing marks. When such
cases are encountered,
transfer timing marks from
the old gear to the new.
using a straight edge and
keystock as shown.
39
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