1953 JEEP DJ service

'Jeep'
UNIVERSAL
SERIES
SERVICE
MANUAL

FIG.
D-l—HURRICANE
F4-ENGINE
— END
SECTION
VIEW

1— Intake Valve Spring Retainer

2—
Adjusting
Screw
3—
Nut

4— Rocker Arm
5—
Push
Rod
6— Intake Valve Guide 7— Intake Valve
8— Exhaust Valve
9—
Cylinder
Head
Gasket

10— Exhaust Valve Guide
11— Exhaust
Manifold

12—
Exhaust Valve Spring

13—
Valve
Spring Cover
14—
Oil
Pump
Gear

15— Camshaft

16—
Oil
Pump
17—
Relief
Plunger

18—
Relief
Plunger Spring

19—
Relief
Spring Retainer

20—
Oil
Pan
21—
Drain
Plug

22—
Oil
Float Support

23—
Oil
Float

24—
Crankshaft

25—
Engine
Rear
Plate
26—
Cylinder
Block

27—
Connecting Rod

28—
Oil
Filler
Tube

29—
Piston

30—
Cylinder
Head

31—
Intake Valve Spring
.12—Carburetor 39

'Jeep*
UNIVERSAL SERIES
SERVICE
MANUAL

D
insulator
mountings attached to the frame side

rail
brackets. The
rear
of the engine-transmission
assembly is supported by a rubber insulator
mounting under the
rear
of the transmission on
the frame center cross member.
This
cross member
is bolted to the frame side
rails
so that it can be
dropped when removing the transmission or engine-

transmission
assembly. The rubber insulators allow
free side and vertical oscillation to effectively

neutralize
engine
vibration at the source.

The
rubber
insulator mountings should be inspected
for separation and deterioration by jacking the
power plant away from the frame, near the sup­
ports. Vibration cannot be effectively absorbed by
separated or worn insulators. They should be re­ placed if faulty.

D-4.
Engine
Ground
Strap

To
be sure of an
effective
ground for the electrical

circuits,
a ground strap bridges the right front

engine
support to the chassis. The connections of this strap must be kept clean and tight for proper
operation of the electrical system.

D-5. ENGINE REMOVAL

Should
the
engine
require overhauling, it is neces­

sary
to remove it from the vehicle. The following procedure covers removal of the
engine
only.

The
engine, transmission and transfer case may be
removed as a unit by removing (in addition to the following procedure) the radiator guard and the
access plates in the floor pan.

a.
Drain
the cooling system by opening the
drain
cocks at the
bottom
of the radiator and lower right
side of the cylinder block.

b.
Disconnect the battery at the positive terminal
to avoid the possibility of short
circuit.

c. Remove the air cleaner horn from the carburetor
and
disconnect the breather
hose
at the oil filler
pipe.

d.
Disconnect the carburetor choke and throttle controls by loosening the clamp
bolts
and set
screws.

e. Disconnect the fuel-tank-to-fuel-pump line at the fuel pump by unscrewing the connecting nut.
f- Plug the fuel line to prevent fuel leakage.
g. Remove the radiator and radiator grille support

rods.

h. Remove the upper and lower radiator
hoses
by
loosening the
hose
clamps and slipping the clamps
back
on the
hose.
If so equipped, remove the heater

hoses
(one to the water pump, one to the
rear
of
the cylinder head) in the same manner.

i.
Remove the four
bolts
from the fan hub and re­

move
the fan hub and fan blades.

j.
Remove the four radiator attaching screws. Re­
move
the radiator and shroud as one unit, k. Remove the starting motor cables. Remove the

starting
motor.

I.
Disconnect the wires from the alternator or
generator. Disconnect the ignition
primary
wire
at the ignition coil.
NOTE:
ON
ENGINES EQUIPPED WITH EX­

HAUST
EMISSION CONTROL, REMOVE THE
AIR
PUMP,
AIR
DISTRIBUTION
MANI­
FOLD,
AND
ANTI-BACKFIRE (DIVERTER)

VALVE.
SEE SECTION
Fl
FOR PROCEDURE.
m.
Disconnect the oil pressure and temperature
sending unit wires at the units.

n.
Disconnect the exhaust pipe at the exhaust
manifold by removing the stud nuts.

o.
Disconnect the
spark
plug cables at the plugs

and
remove the cable bracket from the rocker arm cover stud.

p.
Remove the rocker arm cover by removing the
attaching stud nuts.

q.
Attach a lifting bracket to the
engine
using
existing head bolt locations. Be sure the
bolts
selected
will
hold the
engine
with the weight

balanced.
Attach lifting bracket to a boom hoist,

or
other lifting device, and take up all slack,
r.
Remove the two nuts and
bolts
from each front

engine
support. Disconnect the
engine
ground strap.
Remove the
engine
supports.
Lower
the
engine
slightly to permit access to the two top
bolts
on
the flywheel housing.
s. Remove the
bolts
which attach the flywheel
housing to the engine.

t.
Pull
the
engine
forward, or
roll
the vehicle back­

wards,
until the clutch clears the flywheel housing.

Lift
the
engine
from the vehicle.

D-6. ENGINE DISASSEMBLY

Engine
disassembly is presented in the sequence to be followed when the
engine
is to be completely
overhauled after removal from the vehicle. Some
of the operations of the procedure are also ap­
plicable
separately with the
engine
in the vehicle,

provided
that wherever necessary the part of the

engine
to be worked on is first made accessible by
removal
of
engine
accessories or other parts.

When
the disassembly operations are performed

with
the
engine
out of the vehicle, it is assumed,
in
this procedure, that all of the accessories have been removed
prior
to starting the disassembly

and
the oil has been drained.
In
addition to the instructions covering operations
for disassembling the
engine
out of the vehicle,

special
instructions are given to cover different
operations required when disassembly is
done
with the
engine
installed.

During
disassembly operations, the
engine
should
be mounted in a suitable
engine
repair
stand. Where

practicable,
modify or adapt an existing repair

stand
as necessary to accommodate the engine. If

an
engine
repair stand is not used, take care to

perform
disassembly operations in a manner that

will
protect personnel against an accident and the
engine
and its parts against damage.

NOTE:
If the
engine
is being disassembled because
of possible valve failure, check the valve tappet
clearance
before disassembly. Improper valve

clearance
could be the possible cause of valve

failure,
indicating a need for more frequent valve
checks and adjustments. 41

'Jeep*
UNIVERSAL SERIES SERVICE
MANUAL

FIG.
D-4—F4-134
ENGINE

1— Dowel Bolt
2— Bolt
3— Flywheel Ring Gear
4— Flywheel 5—
Clutch
Pilot Bushing
6— Lockwasher
7— Nut
8— Flywheel Housing
9—
Cable

10— Engine Plate (Rear)
11— Woodruff Key
12— Camshaft Thrust Plate
13— Spacer
14— Camshaft Gear
15— Washer
16—
Crankshaft
Shim (.002 *)
17—
Crankshaft
Thrust Washer
18—
Crankshaft
Gear
19— Spacer
20—
Oil
Slinger
21—
Crankshaft
Oil Seal
22— Packing Ring
23—
Gear
Cover Gasket
24—
Gear
Cover
25—Pulley

26—
Crankshaft
Pulley Nut
27—
Timing
Indicator
28— Engine Support Front Insulator
29—
Front
Engine Plate
30— Bolt 31—
Front
Plate Gasket 14251
43

'Jeep'
UNIVERSAL SERIES SERVICE
MANUAL

D
Remove the screws and lockwashers that attach
the main bearing caps to the cylinder block. Use
a
lifting bar beneath the ends of each bearing cap.

Be
careful not to exert too much pressure to cause
damage to the cap or
dowels
and pry the caps free.

CAUTION:
If main bearing caps are not removed
carefully
by raising both sides of each cap evenly

until
free of the dowels, the
dowels
may be bent.

A
bent main bearing cap dowel can cause misalign­ ment of the cap and resultant
rapid
bearing wear
necessitating replacement. Therefore, remove each
main
bearing cap carefully. If there is reason to
believe any of the
dowels
have been bent during
the bearing cap removal, remove them and install
new
dowels
as detailed in Par. D-34c.
Remove the upper
half
of the
rear
main bearing

oil
seal from the cylinder block and the lower
half

from
the oil seal
groove
in the
rear
main bearing

cap.
Install
the main bearing caps and bearings on
the cylinder block in their original positions.

Note;
Removal of the crankshaft may be ac­
complished only with the
engine
out of the vehicle.

D-27.
Remove
Exhaust
Valves and Springs
Access to the valve chamber is obtained by re­ moving the attaching parts and the valve spring
cover and gasket from the cylinder block. Use cloths
to block off the three
holes
in the exhaust valve
chamber to prevent the valve retaining locks falling
into the crankcase, should they be accidentally dropped.

With
a valve
/
spring compressor, compress the valve springs on
those
valves which are in the
closed position (valve seated against cylinder

block).
Remove the exhaust valve spring retainer

locks,
the exhaust valve spring retainer, and the exhaust valve spring. Close the other valves by
rotating the camshaft and repeat the above opera­
tion for the other valves in the same manner.
Lift

out all the exhaust valves and tag or place them in
a
rack
to indicate the location where each was re­moved from the cylinder block. If a valve sticks in
the guide and cannot be easily lifted out,
pull
the valve upward as far as possible and remove the

spring.
Lower
the valve and remove any carbon

deposits
from the valve stem.
This
will
permit re­ moval of the valve.

For
intake valve and spring removal, see
Par.
D-l7.

D-28.
Remove Camshaft

a.
Push the intake and exhaust valve tappets into the cylinder block as far as possible so the ends of
the tappets are not in contact with the camshaft. b. Secure each tappet in the raised position by in­
stalling a common clip-type clothes pin on the

shank
of each tappet or tie them up in the valve
chamber.

c. Remove the camshaft thrust plate attaching
screws.
Remove the camshaft thrust plate and

spacer.

d.
Pull
the camshaft forward out of the cylinder
block using care to prevent damage to the cam­
shaft bearing surfaces.
D-29.
Remove Valve Tappets
Remove the intake and exhaust valve tappets from
the
bottom
or crankshaft side of the cylinder block
after the camshaft has been removed. Tag each
tappet or place them in a marked
rack
so they may be reassembled in their original positions.

D-30.
Remove Oil
Gallery
Plugs
Remove the plug at each end of the oil gallery in the cylinder block.
This
operation is only applicable
when the
engine
is out of the vehicle and
will
allow access to the oil gallery so it may be cleaned.

D-31. ENGINE INSPECTION
AND
REPAIR
The
inspection and repair procedures detailed here­

in
are recommended to be followed when a com­
plete
engine
overhaul is to be made with the
engine

out of the vehicle. These instructions can generally be applied individually with the
engine
in the
vehicle. Wherever the procedure differs due to
the
engine
being in the vehicle, the necessary

special
instructions are provided. Inspection and

repair
instructions are included to cover the

cylinder
block, cylinder head, crankshaft and bearings, connecting rods and bearings, oil pump, valves and tappets, pistons and rings, flywheel,
timing gears, and the camshaft and bearings. In addition, fitting operations for
these
engine
com­

ponents
are included.

Important:
Before the inspection and repair pro­
cedures listed below are begun, the
engine
serial
number must be checked for the presence of
code

letters denoting undersize bearings or oversize
pistons. Refer to Par. D-2.

D-32.
Cylinder
Block

The
cylinder block must be thoroughly cleaned, inspected and repaired as detailed in the following

paragraphs.

D-33.
Cleaning

The
cylinder block may be steam cleaned or cleaned

with
a suitable solvent. A scraper is recommended
to remove
hard
deposits, except on highly finished surfaces. Special attention must be directed to the
cleaning of the oil passages, valve chamber,
crank­

case, and cylinder walls to remove all sludge,
dirt

and
carbon deposits. After cleaning, use air pressure to dry the block thoroughly.
D-34. Inspection

Examine
the cylinder block for minute cracks and

fractures.
Rusted valve springs or evidence of rust

in
the valve chamber or the cylinder walls is a
good

indication of a possible
crack
in the block,

a.
Examine all machined surfaces of the cylinder block for
burrs
and scores.
Check
for cylinder block
distortion by placing a straight
edge
along the
length of the cylinder head surface of the block.
With
a feeler
gauge,
check for clearance
between
the straight
edge
and the block, particularly be­
tween adjacent cylinders. Maximum permissible
out of line for service is .010"
[0,254
mm.] over the
full
length of the block. 45

'Jeep*
UNIVERSAL
SERIES SERVICE
MANUAL

D
straight
in the hole, then tap the dowel lightly

with
a hammer until it
bottoms.

d.
When installing bearing eaps, be sure to tighten
the
bolts
evenly in each cap to
pull
it into place
without bending the
dowels
or distorting the
bearing
cap.
e. Other parts of the block which require inspec­ tion
and
possible
repair,
but which are directly
related
to other
engine
components (such as tappets, pistons, camshaft, valves, crankshaft, and

oil
pump) are covered later in this section.

D-35.
Cylinder
Bores

The
cylinder bores may be reconditioned by honing
or
reboring. Use oil-soaked rags to protect
crank­

shaft
journals
and other
engine
parts from abrasive
dust during all reconditioning operations.

Both
honing and reboring of the cylinders must be
done
carefully to fit the pistons and to obtain
specified clearances. If reboring of the cylinder bores is not required but the walls are glazed, use

a
finishing
hone
to remove the glaze. Reboring the cylinders must not be attempted unless ade­
quate facilities and experienced service technicians
are
available. The amount of material to be re­moved is determined from the original diameter
of the cylinder bores (3.125" to 3.127") [79,375 a
79,426
mm.] plus the amount of oversize in diameter
of the oversize pistons to be fitted. Pistons are
available
in the following oversizes.
.010"
[0,254
mm.] .030" [0,762 mm.] .020" [0,508 mm.] .040" [1,016 mm.}

The
largest cylinder bore
will
determine the over­
size to which all cylinders must be rebored, since the size and weight of all pistons must be uniform
to maintain proper
engine
balance. The maximum rebore should not exceed .040" [1,016 mm.] from

standard.
Measure
the cylinder diameters by making mea­
surements both parallel to and at right angles to
crankshaft
over entire piston travel and at
bottom

of cylinder. Proceed as follows:

a.
If bores are scored; if out-of-round
exceeds
.005
"
[0,127 mm.]; if diameters differ more than .005";

or
if taper
exceeds
.005
"
on diameter, it is generally
recommended that cylinders be reconditioned by
reboring
and honing to the next oversize using new
pistons of the proper size.

Note:
If reboring is performed, allow .0015"
[0,0381
mm.] for final honing.

All
cylinder bore diameters must be within .002
"
[0,0508
mm.] after reconditioning.

b.
If bore measurements are within the above

limits,
but indicate hollows or waviness, cylinders should be honed with 250 grit
stone
hone. Pump
hone
up and down in cylinder while it is rotating
to produce a satin-finish, diamond cross-hatched

pattern
approximately 30° with horizontal. Hone
only enough to correct waviness.
c. If cylinder bore correction is unnecessary, break the glaze on cylinder walls with a 250 grit
stone

hone
or with a suitable deglazing tool. Operate the
hone
or deglazer to obtain diamond cross-hatched

pattern
previously mentioned.

d.
Regardless of type of correction on cylinder
walls,
wash out bores thoroughly afterwards and
apply
a light coat of
engine
oil. If cylinders have
been rebored or honed heavily, measure cylinder
diameters again to assure proper selection of piston
size.

D-36.
Pistons, Rings, and Connecting Rods
Pistons are each fitted with three rings, two com­ pression rings and one oil control
ring.
The pistons have an extra
groove
above the top ring which acts as a heat dam or insulating
groove
to protect
against sealing of the top ring in the ring
groove

with
hard
carbon. The piston pin is secured by the lock screw.

The
pistons and connecting rods were removed from
the
engine
as assemblies. If cylinders were rebored,
new oversized pistons and rings
will
have to be in­

stalled.

Disassemble the pistons and rods. Remove the
two compression rings, the oil control
ring,
and the oil control ring expander from each piston. Do not remove the
bolts
from the lower end of the
connecting rods unless the
bolts
are damaged.
Clamp
each connecting rod and piston assembly

in
a padded bench vise and remove the piston pin

lock
screw and lockwasher. Press the piston pin
out of the piston and connecting rod.
Clean
all
carbon,
gum, and lacquer
deposits
from both the

inner
and outer surfaces of each piston, connecting

rod,
and piston pin. Use a ring
groove
cleaner or a
broken
ring filed to a sharp square
edge
to clean
the carbon from the piston ring
grooves
and the

insulator
groove. Use care not to scrape metal from
the sides of the
grooves
or make
burrs
on ring
groove
surfaces. Run a length of wire through the

oil
spray
hole
near the lower end of the connecting

rod
to clear the
hole
of hardened oil
deposits
or
foreign matter.
Carefully
inspect the pistons and
replace
any that are broken or cracked. Replace
pistons if any of the ring lands are chipped, broken,
or
rounded on the
edges;
or if the piston is scored,

scratched,
or burned so seriously that the imperfec­
tions cannot be removed with a hand honing
stone

or
crocus cloth.

Replace
the pistons as follows:

a.
After cylinder bores have been carefully checked for out-of-round and taper (Par. D-35), check fit
of each piston to cylinder bore with block and
pistons clean and dry and at approximately 70
°F.
[21°C]
by using Piston Fitting Gauge And Scale

Tool
No. C-690 as shown in Fig. D-7. Use a .003"
[0,0762
mm.] thickness
gauge
%" [19 mm.] wide.

The
piston is fitted upside down in the block to
facilitate the operation. The
gauge
must extend the
full
length of the piston on the thrust side
(opposite

side from slot in piston
skirt).
Scale should register
5
to 10 pounds [2,3 a 4,5 kg.]
pull
to remove the
thickness
gauge
from
between
cylinder
wall
and piston. Excessive
pull
indicates need for a slightly

smaller
piston or additional honing of cylinder. In­ sufficient
pull
indicates need for fitting a larger piston. 47

'Jeep'
UNIVERSAL SERIES
SERVICE
MANUAL

D

FIG.
D-ll—CHECKING PISTON
AND
CONNECTING
ROD
ALIGNMENT 1—
Feeler
Gauge

2—
Fixture

the
opposite
side from the oil spray
hole
in the
bearing
end of the connecting rod. See Fig. D-10.

Install
the piston pin lock screw and torque 35 to
41 lb-ft. [4,8 a 5,7 kg-m.].

d.
Place piston and rod assembly in a connecting

rod
aligning fixture and check alignment of the
assembly as shown in
Fig. D-ll.
Follow instructions

furnished
with the fixture.
e. Using a feeler
gauge
and new piston rings, check the width of the two compression ring
grooves
and
the oil ring groove. Replace the piston if the widths of the
grooves
are not with the limits given in
the specifications.
Insert
feeler
gauge
between
ring and piston to back
of groove. Replace piston if ring
grooves
are not

within
allowable tolerances. If a feeler
gauge
larger
FIG.
D-l 2—CHECKING PISTON RING

SIDE
CLEARANCE
1—
Feeler
Gauge
2—
Piston
Ring
FIG.
D-13—PISTON
RING
GAP
than
.006" [0,152 mm.] can be inserted
J^6"
[1,6
mm.]
between
piston and upper compression
ring,

groove
is worn excessively bell-mouthed and
piston should be replaced.
f.
Check
piston ring end gap by placing compres­ sion ring in cylinder bore below ring travel using head of an inverted piston as a plunger to push

ring
in squarely. End gap must be as shown in

Par.
D-37 for all rings. If less, file ends to obtain
minimum
gap.
With
cylinders bored to an exact

ring
oversize of
+.020", +.030",
or
+.040"
[0,508-

0,762-1,016
mm.] the proper end clearance as given in Par. D-37
will
result. If end
gaps
are
not within the limits given in Par.
D-3
7, rings are
of the wrong size or were incorrectly filed for fitting.

g.
Install
a new ring set using either production replacement rings or service type oil control rings.
Production
type replacement piston rings are the
same as the original factory-installed rings while
service oil control ring
sets
have different com­
ponents, notably the oil ring expander. Follow
instructions of
manufacturer
for proper installation.

Use
a piston ring expander to install rings on pistons. Do not expand rings more than necessary
to install, also be careful not to
burr
the piston

with
ends of rings.
Install
bottom
(oil) ring first, center ring second, and top ring last.

The
width of the compression rings is [2,38
mm.] and that of the oil control ring is f^" [4,78

mm.].
While the compression rings are of the same
size, they are different in construction and must
not be interchanged.
Install
these
rings as shown

in
Fig. D-14. The upper compression ring has an
inside beveled
edge
which must be installed toward
the piston top. The face of the lower compression

ring
is tapered approximately .001" [0,025 mm.].
The
letters T or TOP on the upper
edge
indicate
how the ring is to be installed. 49

-Jeep*
UNIVERSAL
SERIES SERVICE
MANUAL

E>
[5,928 a
5,926
cm.] for all main bearings. Allowable
taper or out-of-round of the journals is .001"
[0,0254
mm.].

D-42.
Checking Connecting Rod
Crankpins

Check
the crankpin diameters with a micrometer
to ensure that they are not out-of-round or tapered more than .001"
[0,0254
mm.] The standard
crank-

pin
diameter is
1.9383*
to
1.9375"
[4,9233
a
4,9213

cm.].
D-43.
Crankshaft
Main
Bearings

The
crankshaft rotates on three main bearings

with
a running clearance of .0003" to .0029"
[0,0076
a
0,0736
mm.].

These
bearings are positioned and prevented from
rotating in their supports in the cylinder block by
dowel pins. Dowel pins are used in both the center

and
the
rear
bearing caps. No dowel pins are used

in
the front bearing cap because the bearing has
a
flange. The front main bearing takes the end

thrust
of the crankshaft. The main bearings are of premium type which provides long bearing life.
They
are replaceable and when correctly installed, provide proper clearance without filing, boring,

scraping,
or shimming. Crankshaft bearings can
be removed from this
engine
only with the
engine

out of the vehicle. Crankshaft bearings must be replaced as a complete set of three bearings, each
bearing consisting of two halves.
Main
bearings
are
available in the standard size and the following
undersizes:
.001" [0,025mm.] .012" [0,305 mm.] .002" [0,051mm.] .020" [0,508 mm.] .010" [0,254mm.] .030" [0,762 mm.]

The
.001" and .002" undersize main bearings are
for use with standard size crankshafts having
slightly worn
journals.
The .010", .020", and .030" undersize bearings are for use with undersize

crankshafts
in
those
sizes. The .012" undersize
bearings are for use with .010" undersize
crank­
shafts having slightly worn journals. Bearing sizes

are
rubber stamped on the reverse side of each
bearing half.
D-44. Crankshaft
Main
Bearing Inspection

The
crankshaft
journals
must be carefully inspected
as detailed previously in Par. D-41. Worn journals

will
require undersize bearings. Scored, flaked, or

worn
bearings must be replaced. Measure the main
bearing bores in the cylinder block using a
telescope

gauge
and micrometer. Measure the bores at right
angles to the split line and at 45° to the split line.

The
bores should not be over .001"
[0,0254
mm.]
out-of-round or .001" in taper from end to end.

Also,
the bores should not be more then .001"
oversize, considering the average diameter of the
bore.

D-45.
Fitting Crankshaft
Main
Bearings
Using
Plastigage

After
wiping and carefully inspecting the bearing bore, install the proper bearing. See that the oil

hole
in the bearing upper half registers properly

with
the oil
hole
in the block, and that the bearing
lock fits properly in the notch in the block.
Install

the crankshaft if replacing bearings with the
engine

out of the vehicle. The desired running fit (dif­
ference
between
the diameter of the crankshaft

journal
and the inside diameter of the fitted bear­ ing) for a main bearing is .0003" to .0029"
[0,0076

a
0,0736
mm.]. With a dimension in
excess
of this
standard
running fit, a satisfactory bearing replace­ment cannot be made and it
will
be necessary to

regrind
the crankshaft.
Install
the bearing lower

half
and the bearing cap and draw the nuts down
equally and only slightly tight. Rotate the
crank­

shaft by hand to be sure it turns freely without

drag.
Pull
the nuts tighter, first one then the other,
a
little at a time, intermittently rotating the
crank­

shaft by hand until the recommended torque of
35 to 45 lb-ft. [4,8 a 6,2 kg-m.] is reached. If the
bearings are of the correct size, and lubricated with
light oil before installation, the crankshaft should
turn
freely in the bearings. If the crankshaft cannot
be turned, a larger bearing is
required.
If there is no binding or tightness, it is still necessary to check
clearance to guard against too
loose
a fit. Never file
either the bearing cap or the bearing to compensate
for too much clearance. Do not use shims under a
bearing cap or behind a bearing shell. Do not run a
new bearing half with a worn bearing half. The use
of "Plastigage" of the proper size to measure .001" [0,025 mm.] clearance is recommended for check­
ing crankshaft main bearing clearance. The method
of checking clearance is as follows:

a.
Remove the bearing cap and carefully wipe

all
oil from the bearing and the
journal.
b.
Lay a piece of "Plastigage" y%" [3 mm.]
shorter than the width of the bearing across the

journal
(lengthwise of the crankshaft).

c.
Install
the bearing and cap and tighten first
one nut, then the other, a little at a time to the specified torque. As the bearing
tightens
down

around
the
journal,
the "Plastigage" flattens to a
width that indicates the bearing clearance.

d.
Remove the cap and measure the width of
the flattened "Plastigage," using the scale printed
on the
edge
of the envelope. The proper size "Plasti­
gage"
will
accurately measure clearance down to .001".
e. If the flattened "Plastigage" tapers toward the middle, or toward the end, or both ends, there
is a difference in clearance, indicating a taper, a
low
spot,
or other irregularity of the bearing or

journal.

D-46.
Fitting Crankshaft
Main
Bearings
Using
Shim Stock

Thin
feeler or shim stock may be used instead of "Plastigage" to check bearing clearances. The
method is simple, but care must be taken to protect
the bearing metal surface from
injury
by too much pressure against the feeler stock,

a.
Cut a piece of .001" [0,025 mm.] thick, by Yl [12,7 mm.] wide, feeler stock }4" [3 mm.]
shorter than the width of the bearing. Coat this 51

'Jeep'
UNIVERSAL
SERIES
SERVICE
MANUAL

D
satisfactory bearing replacement cannot be made

and
it
will
be necessary to regrind the crankshaft.

Install
the bearing lower
half
and the connecting

rod
cap and draw the cap bolt nuts down equally
and
only slightly tight. Move the connecting rod
endwise, one way or the other, on the crankshaft to be sure the bearing is not tight.
Pull
the nuts tighter, first one then the other, a little at a time,

and
keep trying the fit of the rod on the crankshaft by hand until the recommended torque of 35 to 45 lb-ft. [4,8 a 6,2 kg-m.] is reached. If the
bearings are of the correct size, and have been
properly
lubricated with light
engine
oil before in­

stallation,
the connecting rod should be easy to
slide back and forth parallel to the
crankpin.
If
the connecting rod is tight on the crankshaft, a

larger
bearing is required. If there is no binding

or
tightness, it is
still
necessary to check clearance
to guard against too
loose
a fit. The use of "Plasti­

gage"
or shim stock of the proper size to measure .001" [0,025 mm.] clearance is recommended for

checking
connecting rod bearing clearances.
This

is the same material recommended for checking
crankshaft
main bearings and the method of check­
ing is
similar.
Refer to
Par.
D-45 or D-46. Connect­
ing rod bearings are fitted to the same clearance as the main bearings but the torque specified for con­
necting rod cap
bolts
is different.

D-50.
Connecting
Rod
Side Play

Check
the connecting rod side play with a feeler
gauge
as shown in Fig. D-l8. The side clearance is .004" to .010"
[0,101
a
0,254
mm.].

D-51.
Camshaft and Bearings

The
camshaft is supported at four points in the

cylinder
block. The front is supported in a re­ placeable, steel-shell, babbit-lined bearing. The

bearing
is pressed into place The other three bear-
FIG.
D-18—CONNECTING
ROD
SIDE
PLAY
ing surfaces are precision machined in the cylinder
block. The camshaft bearings are pressure
lubri­

cated through drilled passages in the crankcase.

End
thrust of the camshaft is taken by a thrust plate bolted to the crankcase. The camshaft is

driven
by a silent helical-cut
tooth
timing gear at
the front of the engine. A worm gear, integral with
the camshaft, drives the oil pump and distributor.

The
fuel pump is actuated by an eccentric forged

onto
the camshaft.

Clean
the camshaft thoroughly in cleaning solvent.
Inspect
all camshaft bearing surfaces to determine

if
they are scored or rough. The cam faces must be
perfectly smooth throughout their contact face

and
must not be scored or worn.

D-52.
Camshaft
Front Bearing Replacement

Use
a suitable driver to remove the camshaft front
bearing
from the cylinder block. To install a new
bearing,
align the oil
hole
in the bearing with the
bored oil
hole
in the cylinder block and drive the

bearing
in until the front end of the bearing is

flush
with the front surface of the cylinder block.

Make
sure the oil
hole
is open and clear. It is not
necessary to line-ream the bearing after installation because bearings for replacement are precision
reamed
to the finished size. Do not stake the

bearing.

D-53-
Camshaft End Play

End
play of the camshaft is determined by running
clearance
between
the
rear
face of the camshaft gear and the thrust plate and is established by the

spacer
thickness. The standard clearance is .004"
to .007"
[0,101
a 0,178 mm.] and can be measured by a
dial
indicator. As a general rule this clearance

will
change but little through wear or when a new gear is installed. To predetermine the correct end
float with the gear, spacer, and thrust plate re­
moved, measure the thickness of both the thrust
plate and spacer with a micrometer. The thickness
of the spacer should be approximately .006" [0,152 mm.] greater than that of the thrust plate.

When
this is correct and the parts are assembled

and
drawn tightly
together
by the gear retaining

screw,
the end play should
come
within standard
limits.

D-54.
Timing Gears
and
Cover

The
timing gears are mounted at the front of the
engine. Camshaft drive is through helical-cut
timing gears; a steel gear on the crankshaft and a
pressed fiber gear on the camshaft. The gears are keyed to their respective shafts. The camshaft

driven
gear is secured on the front end of the
camshaft by means of a capscrew and a plain

washer.
The crankshaft gear is secured on the
front end of the crankshaft by a nut threaded
onto
the front end of the crankshaft holding the
crank­

shaft pulley, crankshaft oil slinger, and the
crank­

shaft drive gear spacer. The timing gears are

lubricated
through a jet threaded into the
crank­
case directly above the gear contact and oil supplied
through a drilled passage from the front main

bearing.
The timing gears are enclosed by the
sealed timing cover. The oil seal in the cover bears 53