Paragraphs 86-89
Fig.
AC34—Models B, C, CA, and RC camshaft installation. Camshaft rotates on three re-
newable split type bushings. Camshaft end play is controlled by thrust plunger (11) and
, spring (10),
1 Cam gear 6, Oil pump drive pin 10, Thrust plunger spring
2] Camshaft gear key 7. Rear bushing U. Thrust plunger
3 Front bushing 8. Central oil passage 12. Oil slinger unit
4.
Valve tappet 9. Oil hole for rod bearing 13. Timing gear cover
5] Center bushing lubrication
Fig, AC35-Models WC, WD, WD45 and WF camshaft installation. Camshaft rotates on
three renewable split type bushings.
1.
Expansion plug
2.
Pipe plug
3.
Rear bushing
4.
Center bushing
5.
Valve tappet
6. Front hushing
7,
Cam gear
8, Gear retaining cap screw
9, Timing gear cover
10.
Locknut
11.
Thrust screw
12.
Metered oil i
rear of block. Drive center bushing in
until it extends 1/16 inch beyond both
ends of bearing boss. Drive front bush-
ing in until front edge of bushing is
flush with front face of block. Bush-
ings are presized and should be driven
in with a plug-type driver. The diam-
eter of the plug should be 1.751 inches.
Be sure oil hole in bushings registers
with oil passage in cylinder block.
Journal Diameter (Mean)
1.749S
Running Clearance .002-.004
Model G
86.
To remove camshaft, flrst re-
move the camshaft gear, as outlined
in preceding paragraphs. Remove the
ignition distributor and cylinder head
and either block up, or remove, the
valves and tappets. Remove camshaft
thrust plate from front of cylinder
block and withdraw the shaft.
Camshaft journals ride directly in
3 machined bores of the cylinder block.
Shaft journal sizes are: Front and cen-
ter
1.7S0;
rear
1.2S0.
Recommended
clearance of journals in bores is .003
to .004S. The maximum permissible
clearance is .007 and when it exceeds
this amount it will be necessary to
renew the camshaft and/or the cylin-
der block, or both, or to make up
and install bushings.
Camshaft end play is controlled by
the thickness of the thrust plate (10—
Fig, AC27) located behind the gear.
Renew the thrust plate if the end play
exceeds .007. Check the vent opening
(X) in the camshaft directly behind
the front camshaft journal. If the hole
is plugged, it will be impossible to ob-
tain satisfactory governor operation.
Models WC-WD-WD45-WF
87.
To remove camshaft, remove
timing gear cover, flywheel cover, oil
pan and oil pump. Remove cylinder
head cover, rocker arms assembly and
push rods and remove cam gear from
camshaft. Hold tappets up to clear
cams and withdraw camshaft. When
reinstalling camshaft, be sure oil pas-
sages are clean. Metering hole in plug
(12—Fig. AC35) is discontinued in
later WD and all WD4S models which
have a solid plug. Adjust camshaft
end play after timing gear cover has
been installed, by loosening locknut.
ALLIS-CHALMERS
turning thrust screw (11) in until it
bottoms, then back l^% turn.
Clearance between new camshaft
and each of the three split type cam-
shaft bushings should be .002-.004
inch. Renew camshaft bushings or cam-
shaft or both if clearance exceeds ,006
inch. Bushings are supplied in Stan-
dard size and undersize of 0.0025,
To renew camshaft bushings after
camshaft has been removed, it is neces-
sary to remove the
fl3^wheel
which ne-
cessitates engine removal. Bushings can
be driven out of block and new ones
driven in. Drive rear bushing out to-
wards the rear, driving expansion plug
with it. Bushings are pre-sized and
should be driven in with a plug-t3T)e
driver. The diameter of the plug should
be 1,875 inches. Be sure oil hole in bush-
ing registers with oil passage in cylinder
block. When installing expansion plug
(1) in rear of block, be sure it seats
tightly and seals completely.
Journal Diameter (Mean)
1.8745
Running Clearance .002-004
ROD AND PISTON UNITS
Models B-C-CA-RC
88.
Connecting rod and piston as-
semblies are removable from above af-
ter removing oil pan and cylinder head.
Connecting rods are offset. Numbers 1
and 3 have the long part of the bearing
toward the flywheel, and Numbers 2
and 4 have the long part toward the
timing gears. Tighten connecting rod
bolts to 35 foot pounds.
Model G
89.
Piston and rod units are re-
moved from below and only from the
side opposite the camshaft. The lower
portion of the cylinder bore is
chamfered 45 degrees to permit instal-
lation of rings without using a ring
compressor. Pistons and rods are in-
stalled with the rod cap correlation
marks toward the camshaft. Replace-
ment rods are not marked and should
be installed with the oil spray hole at
lower end of rod facing the camshaft,
and with the piston slot facing opposite
to camshaft side. Because of the close
quarters in the crankcase end of the
block, some mechanics claim time can
be saved by reinstalling the assemblies
from below, without any rings on the
pistons. They then push the pistons up
as far as they will go and assemble the
rings to their piston grooves above the
top face of the block.
A
ring compressor
is then used to enter the rings into
their cylinder bores. Tighten the con-
necting rod cap screws to 20-25 ft. lbs,
torque.
18
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