1953 JEEP DJ fuel

c

TUNE-UP
meter during this
test
Connect the red lead
tc*
dis­

tributor
primary
lead at the coil as shown in Fig.
C-21.
Connect black lead to the ground.
Turn

ignition switch on; with
engine
stopped, observe
dwell
meter. If the meter reads zero,
crank
the

engine
a fraction of a revolution to
close
the

breaker
points.

Distributor
resistance is normal, if dwell meter
pointer is within range of
black
bar. Distributor resistance is high, if
dwell
meter pointer is not

within
the black bar.
Remove test lead from
distri­
butor terminal of coil and
connect
to
each
of the
following points to determine
where
the excessive resistance is:

Distributor
primary
terminal

Distributor
primary
terminal in the distributor

Breaker
point bracket
Ground
side of points

Distributor
housing

Where
a noticeable change occurs in the meter
reading
in
these
steps, make the necessary correc­
tion and repeat the
test.

C-l 7. Distributor
Point
Dwell

Using
a dwell tester, connect red
lead
to the
distri­

butor terminal at coil. Connect black lead to
ground.
Set selector switch to the number of
cylin­

ders in the
engine
being tested. Operate
engine
speed at specified rpm. and
note
readings. Cam

dwell
angle must be 30° for the Dauntless V-6
Delco equipped engine, 29° ±: 3° Prestolite equipped
engine
and 42° for the
Hurricane
F4 engine. If the dwell reading is not to specifications,
trouble could be improper point spacing, point

rubbing,
defective block or breaker arm, or mis­
aligned and worn distributor cam.
Adjust
dwell
as shown in Fig. C-14 for the Delco equipped
Dauntless V-6 engine. For cam dwell adjustment
of the Prestolite equipped V6 and
Hurricane
F4 engine, refer to Par. C-10,
step
a.

Dwell
variation is determined by noting any
dwell
change as the
engine
is operated at different
speeds.

Excessive
variation indicates a change in point opening that can result from shaft or bushing wear,

or
from the distributor plate shifting because of

wear
or
looseness.

Measure
dwell variation at idle speed, using same

test
hookup for checking dwell. Increase speed to 1750 rpm.;
note
dwell reading.
Then
slowly reduce
speed to idle while observing dwell meter. Dwell

variation
should not exceed 3°. If dwell variation
exceeds
3°
between
idle speed and 1750 rpm.,
probable wear in the distributor shaft, bushings, or

breaker
plate is indicated. Distributor should then be checked more thoroughly.

C-l8. Check Ignition Wires
and
Connections

Examine
and clean the insulation on all ignition

wires
and check all connections. Wires should be
firm,
flexible, and free from roughness and minute
cracks.
Bend wires to check for brittle,
cracked,
or

loose
insulation. Since defective insulation
will
per­

mit
crossfiring or missing of the engine, defective

wires
should be replaced.

C-l9. Test Ignition
Cables

To
remove cables from
spark
plugs, use
Spark
Plug
Cable
Remover
Tool
W-274.
Twist
the
boot

slightly to break the seal and, grasping the rubber
protector
boot,
lift straight up with a steady even

pull.
Do not grasp the cable and
jerk
the cable off; this
will
damage the cables. Do not use a probe
on
these
wires; puncturing them may cause a
separation in the conductor. To remove ignition cables from the distributor cap or coil tower,
loosen

the nipple first, then grasp the upper part of the nipple and the cable and gently
pull
straight up.

Test
the cable with an ohmmeter. Resistance value

per
foot
is
3000-7000
ohms. The ignition cables
can
be checked for
circuit
continuity by removing
the cable from the
spark
plug and holding the cable
end Vi" [6,35 mm.] from the engine. A strong

spark
indicates
good
conductor continuity.

When
connecting the cable to the
spark
plug, be
certain
a
good
connection is made and that the
protector
boot
fits tight on the
spark
plug. A
partially
seated cable creates an additional gap in
the
circuit
and the resulting
spark
jump
will
cause

terminal
corrosion and cable damage.

C-20. Coil

When
an ignition coil is suspected of being defec­ tive, it should be checked on the car. A coil may

break
down after it has reached operating tempera­
ture.
It is important that the coil be at operating
temperature when
tests
are made.

Note:
The ignition coil and ballast resistor for the

V-6
engine
must be of the same manufacturer.
Ballast
resistors and ignition coils of one manufac­

turer
are interchangeable with both units of the
other.
C-21.
Service Air
Cleaner

Refer
to Par.
B-2 2
for the correct service of the

air
cleaner.

C-22.
Check Fuel Lines and
Screens

Check
all fuel line connections to guard against
leakage.
Check
fuel pump filter F4
engine
and
fuel
line filter V-6 engine. Replace fuel filter if
necessary.

C-23. Check Fuel Pump a.
Fuel
pump pressure is important, for low pres­

sure
will
seriously affect
engine
operation and high

pressure
will
cause excessive fuel consumption and
possibly flood the carburetor. Should there be any doubt of normal operation, check the pressure with
a
gauge
as shown in Fig.
C-2 2.
The minimum and

maximum
allowable pressures are 2% to 3% lbs. [0,176 a
0,264
kg-cm2], for the
Hurricane
F4 en­
gine.
Fuel
pump pressure at carburetor (inlet) on
the Dauntless V6-225
engine
should be 3% lbs.
[0,264
kg-cm2] minimum at specified
R.P.M.
idle

with
the vapor
return
hose
squeezed off.
With
the

vapor
return
hose
open pump pressure should be
2
V2
lbs. [0,176 kg-cm2] minimum.

b.
Test for volume, as a pump may build up suffi­
cient pressure but
fail
to produce sufficient volume.
Turn
down the carburetor fuel line fitting on the
pump and with the tank line connected, pump out
30

'Jeep'
UNIVERSAL
SERIES
SERVICE
MANUAL

C

FIG.
C-22—-CHECKING
FUEL
PUMP
PRESSURE
—
DAUNTLESS
V-6
ENGINE a
couple of strokes to be sure the pump is primed.

Using
a half-pint
bottle
or similar measure, pump
Vi
pint [0,24 It] of fuel by cranking the
engine

with
the starter motor. Count the strokes neces­
sary
to
fill
the measure. If more than 20 strokes

are
required, the fuel pump is inefficient, the tank
line is leaking air, or the fuel supply is restricted.

Check
fuel filter in the fuel tank if line is restricted.

C-24.
Check Manifold Vacuum

To
check the intake manifold vacuum on the
Hurri­

cane F4 engine, remove the ventilation valve and

L
fitting from the manifold and install special adapter. On the Dauntless V-6
engine
remove the
pipe plug located in the right
rear
of the intake
FIG.
C-23—CHECKING MANIFOLD VACUUM
—

HURRICANE
F4
ENGINE
manifold and install special adapter. Connect the

vacuum
gauge
tube to the special adapter as shown

in
Fig. C-23 for the
Hurricane
F4 engine.

Start
the engine. Connect a Tachometer
Tool,

C-3896,
from the distributor
primary
terminal to ground and set the
engine
speed at the specified

rpm.
given in Par. C-30. Observe the vacuum
read­

ing and interpret as follows:

a.
A steady reading from 18" to 20" [457 a 508
mm.] of mercury is a normal reading, indicating
that valve and
spark
timing, valve seating, and
piston ring sealing are all satisfactory.
b. A steady but below normal reading indicates

a
condition common to all cylinders such as a

leak
at the carburetor gasket, late ignition or valve
timing, or uniform piston ring and bore wear.

c.
A slowly fluctuating or drifting reading in­ dicates that the carburetor idle mixture is incorrect

Look
for the cause in the fuel system.

d.
A rhythmic pulsating reading is caused by a
condition affecting one or more cylinders, but not

all,
and indicates leaky valve, gasket blowby, re­
stricted intake port, or an electrical miss.
e. An intermittent pulsating reading is caused by

an
occasional malfunction, such as a sticking valve
(all
valves may be
erratic
in operation if the valve
springs are weak), electrical miss caused by insuffi­
cient distributor point tension or low coil
voltage

coupled with inconsistent
spark
plug
gaps
or fouled
plugs, or
dirt
in the fuel system finding its way into
passages of
critical
size or valve
seats
in the
car­

buretor.

f.
A normal reading that quickly falls off (with

engine
running at
2000
rpm.) indicates exhaust
back
pressure caused by a restriction in the exhaust
system.

g.
Make indicated corrections to bring vacuum to 18" to 20" [457 a 508 mm.] of mercury normal

reading.

C-25.
Carburetor Adjustments

•
Refer to Fig. C-24, C-25 and C-26.

Carburetor
adjustments should not be attempted

until
it is known that
engine
ignition and com­
pression are in
good
order. Any attempt to adjust

or
alter the carburetor to compensate for faulty conditions elsewhere
will
result in reduced econ­
omy and overall performance.

Caution:
If an
engine
is idling too slow or rough,
this may be caused by a
clogged
ventilator valve

or
hose;
therefore, never adjust the carburetor idle
without first checking the crankcase ventilator
check valve and
hose.

The
air cleaner must be left in place while making
idle speed and mixture adjustments. All lights and accessories, must be turned off. The positive
crank­

case ventilator system should also be in
good
oper­
ating condition when making carburetor adjust­ ments.
Either
of
these
items noticeably affects the

air
fuel ratio at idle.

•
Hurricane
F4 Engine.
Note:
The idle mixture adjustment procedure for
the late model
YF-4941S
and
YF-6115S
Carter

31

c

TUNE-UP
Carburetor
equipped with the
External
Idle Mix­
ture
Limiter
Cap is the same as outlined below
in
Pars.
"A"
through
"D";
however, because of the
Idle
Limiter
Cap,
the idle mixture screw
CANNOT

be adjusted in the counter-clockwise
(rich)
direc­
tion. The adjustment is made from the
rich
stop
position and the mixture screw is turned in (clock­
wise) approximately 3A turn to
"Lean
Best Idle."

Refer
to Fig. C-25.

The
"Lean
Best Idle" method of idle setting is as follows:

a.
Any scheduled service of ignition system should
precede this adjustment.

b.
Connect tachometer or vacuum
gauge
to engine.

c.
Warm
up
engine
and stabilize temperatures.
d.
Adjust
engine
idle to speed desired, using throt­
tle idle speed adjusting screw.

e.
Carburetors without Idle
Limiter
Cap turn idle
mixture screws out (counterclockwise) until a
loss
of
engine
speed is indicated; then, slowly turn mix­
ture screw in (clockwise-leaner) until maximum speed (RPM) is reached. Continue turning in (clockwise) until speed
begins
to drop; turn mix­
ture adjustment back out (counterclockwise-richer)

until
maximum speed is just regained at a "lean as possible" mixture adjustment. Refer to
Fig.
C-24.
FIG.
C-24—CARBURETOR —
HURRICANE F4 ENGINE,
EARLY
MODEL 1—
Choke
Clamp Bracket
2—
Choke
Shaft and
Lever
Assembly

3—
Fuel
Inlet Elbow
4—
Bowl
Vent Tube 5— idle Air Adjusting
Needle
6—
Throttle
Lever
and Shalt Assembly
7—
Idle
Speed Adjusting Screw
8—
Fast
Idle Connector Rod
FIG.
C-25—CARBURETOR —
F4 ENGINE,
LATE
MODEL 1—
Choke
Clamp Bracket
2—
Throttle
Lever
and Shaft

3—
Choke
Shaft and
Lever

4 Bowl Vent Tube 5—
Fuel
Inlet Elbow 6—
Dash
Pot Bracket 7—
Throttle
Lever
8—
Dash
Pot Plunger
9—
Dash
Pot Assembly
10—
Lock
Nut
11— Stop Pin
12—
Idle
Mixture
Limiter
Cap 13—
Idle
Speed Adjusting Screw
14—
Fast
Idle Connecting Rod
Note:
When adjusting the mixture screw never
seat the screw tight during the adjustment proce­

dure
as this can damage the screw needle.

•
Dauntless V-6 Engine.

The
"Lean
Best Idle" method of idle setting is
as follows:
a.
Any scheduled service of ignition system should
precede this adjustment.
b. Connect tachometer to engine.

c.
Warm
up
engine
and stablize temperatures.
d.
Adjust
engine
idle to speed desired, using throt­
tle idle speed adjusting screw.
Note:
The
Carter
YF-6115S
Carburetor
has a throt­
tle return spring attached from the carburetor

main
body to the carburetor throttle shaft The purpose of this spring is to return the throttle
to idle speed position should a linkage failure
occur.
FIG.
C-26—CARBURETOR —
DAUNTLESS V-6 ENGINE 1—
Fuel
Inlet
2—
-Choke
Housing

3—
Choke
Cable Bracket
4—
Idle
Speed Adjusting Screw
5—
Idle
Fuel-Air
Mixture Screws 32

'Jeep*
UNIVERSAL
SERIES
SERVICE
MANUAL

C

FIG.
C-2
7—FAN
BELT
—
DAUNTLESS
V-6
ENGINE
e. Adjust mixture by turning idle mixture screws
out (counterclockwise) until a loss of engine speed
is indicated; then, slowly
turn
both mixture screws

in
clockwise (leaner) until maximum speed (RPM)
is reached. Continue turning in (clockwise) until a slight drop in speed (RPM) is noted. Make certain
both mixture screws are adjusted equally.
This
will

ensure a "lean as possible" mixture adjustment.

Readjust
idle
stop
screw to idle engine at the
specified
R.P.M.

Note:
This
method of adjusting idle mixture must
be used to keep hydrocarbon and carbon monoxide
emissions to a minimum.

Note:
No fast idle speed adjustment is required.

Fast
idle is controlled by the curb idle speed ad­ justment screw. If the curb idle speed is correctly set, the fast idle speed
will
be correct.
C-26.
Dash
Pot
Adjustment

Refer
to Section
E, Par.
E-44 for proper carburetor

dash
pot adjustment procedure.

C-27.
Check
Fan
Belt

The
fan belt drives the fan, alternator, and water

pump.
See Fig. C-27.

Inspect
the fan belt for serviceability and proper
tension. The tension should be checked with the
Belt
Tension Gauge, W-283. The correct tension on a used belt is 70 to 80 pounds [31,7 a 36,2 kg.]

and
on a new belt 110 to 120 pounds [49,8 a 54,5 kg.]. When preparing for delivery of new car,
the belt strand tension should be 80 to 110 pounds [36,2 a 49,8 kg.]. When installing a new belt, adjust
the strand tension 110 to 120 pounds [49,8 a 54,5 kg.].

Adjust
the fan belt tension by loosening the clamp
bolt on the alternator brace and swinging the alter­

nator
away from the engine until proper belt ten­
sion is obtained.
Then
tighten the clamp bolt.

Note:
If no
gauge
is available approximate correct
tension is obtained when the thumb pressure mid­
way between the pulleys causes the belt to flex
y%
inch
[IV4
cm.].

C-28.
ROAD TEST VEHICLE

After
completing the tune-up, road
test
the vehicle for power and overall performance. Make neces­
sary
adjustments.

Note:
Engine run on or "dieseling" is a condition

in
which combustion continues to take place after
the normal ignition
spark
from the distributor has
been shut off by turning off the ignition switch. It is generally caused by excessive engine idle speed

in
combination with retarded ignition timing, en­ gine heat soak or the use of low octane fuel.

Should
engine dieseling (engine running after igni­
tion key is turned off) be experienced on V-6 engine equipped vehicles, installation of Idle Stop
Valve
Kit
Part
No. 991722
will
correct the

difficulty.
33

TUNE-UP

C-29.
SERVICE
DIAGNOSIS

POOR
FUEL ECONOMY Ignition Timing Slow or Spark Advance Stuck

Carburetor
Float High
Accelerator Pump Not Properly Adjusted High Fuel Pump Pressure

Fuel
Leakage

Leaky
Fuel Pump Diaphragm Loose Engine Mounting Causing High Fuel Level in Carburetor

Low
Compression
Valves Sticking
Spark
Plugs Bad

Spark
Plug Cables Bad
Weak
Coil
or Condenser Improper Valve Tappet Clearance

Carburetor
Air Cleaner Dirty
High Oil Level in Air Cleaner Dragging Brakes

Front
Wheels Out of Alignment

Tires
Improperly Inflated Inaccurate Odometer

Faulty
Fuel Tank Cap
Clogged
Muffler or Bent Exhaust Pipe Sticking Exhaust Manifold Valve

LACK
OF POWER
Low
Compression Ignition System (Timing Late)
Improper Functioning Carburetor
or Fuel Pump

Fuel
Lines
Clogged

Air
Cleaner Restricted Engine Temperature High Improper Tappet Clearance
Sticking Valves
Valve Timing Late

Leaky
Gaskets
Muffler
Clogged

Bent Exhaust Pipe Sticking Exhaust Manifold Valve —
Dauntless V-6 Engine

LOW
COMPRESSION
Leaky
Valves Poor Piston Ring Seal Sticking Valves
Valve Spring Weak or Broken
Cylinder
Scored or Worn
Tappet Clearance Incorrect Piston Clearance too Large

Leaky
Cylinder Head Gasket

BURNED
VALVES AND SEATS Sticking Valves or too Loose in Guides
Improper Timing
Excessive Carbon Around Valve Head and Seat Overheating
Valve Spring Weak or Broken
Valve Tappet Sticking
Valve Tappet Clearance Incorrect
Clogged
Exhaust System

Defective
Valve
Lifter
— Hydraulic
VALVES
STICKING
Warped Valve Improper Tappet Clearance Carbonized or Scored Valve
Stems

Insufficient Clearance Valve Stem to Guide
Weak or Broken Valve Spring Valve Spring Cocked Contaminated Oil

OVERHEATING
Inoperative Cooling System
Theromstat Inoperative Improper Ignition Timing
Improper Valve Timing
Excessive Carbon Accumulation
Fan
Belt too Loose

Clogged
Muffler or Bent Exhaust Pipe
Oil
System Failure Scored or Leaky Piston Rings
Sticking Exhaust Manifold Valve — Dauntless V-6 Engine

POPPING-SPITTING-DETONATION
Improper Ignition Improper Carburetion
Excessive Carbon
Deposit
in
Combustion Chambers
Poor Valve Seating Sticking Valves
Broken Valve Spring Tappets Adjusted too Close
Spark
Plug Electrodes Burned
Water or Dirt in Fuel
Clogged
Lines Improper Valve Timing

Clogged
Fuel Filter Sticking Exhaust Manifold Valve —
Dauntless V-6 Engine

EXCESSIVE
OIL CONSUMPTION Piston Rings Stuck in Grooves, Worn or Broken Piston Rings Improperly Fitted or Weak Piston Ring Oil Return
Holes
Clogged

Excessive Clearance, Main and
Connecting Rod Bearings

Oil
Leaks at Gaskets or Oil Seals
Excessive Clearance, Valve Stem
to Valve Guide (Intake)

Cylinder
Bores Scored, Out-of-
Round or Tapered
Too Much Clearance, Piston to Cylinder Bore
Misaligned Connecting Rods
High Road
Speeds
or Temperature
Crankcase
Ventilator Not Operating

BEARING
FAILURE
Crankshaft
Bearing Journal Out-of-Round

Crankshaft
Bearing Journal Rough

Lack
of Oil
Oil
Leakage

Dirty
Oil

Low
Oil Pressure or Oil Pump Failure

Drilled
Passages
in Crankcase or Crankshaft
Clogged

Oil
Screen Dirty
Connecting Rod Bent 34

HURRICANE
F4
ENGINE

D-1.
GENERAL

This
section describes service and repair of the
F4
engine. The
engine
code
number shown in Fig.
A-3
is provided to identify the four cylinder engine.
The
meaning of the coded letters and numbers that

are
stamped on the water pump boss, at the front of the cylinder block, is given below.
Letter
to
Designate
Market

M
—
Military
E
—
Export

D
— Domestic
I
—
Industrial
&
Marine

Letter
to
Designate
Engine
Letter
to
Designate
Year
Built
R
— 1969

S
— 1970

T
— 1971
U—
1972

V
— 1973

W
— 1974

Numbers
to Designate
Compression
Ratio

F
— F4-134
Engine
63
67
•

71
-
6.3 to 1

•
6.7 to 1

-
7.1 to 1

Market
-
D
S F

(Domestic)

(1970)

Engine-
EXAMPLE

123 A B S
(F4-134)

Day- "L

Compression
Ratio

(6.7)
-
Service Engine (S)
Short
Block
(R)

-.010*
Oversize Pistons

(123rd)
-.010*
Undersize
Main

and
Rod Bearings
All
disassembly and assembly procedures are
presented in logical order, assuming a complete

engine
overhaul with
engine
removed from the vehicle. However, many of
these
procedures can
also be performed as on-vehicle services if vehicle
or
engine
components are removed to gain access
to parts involved.

Note:
Some
engines
are equipped with an exhaust
emission control system. Service information on
the components of this system is given in Section

F-l.
D-2.
Description

The
Hurricane
F4-134
engine
is an F-head, four-
cyiinder
engine
of combination valve-in-head and valve-in-block construction.
Large
intake valves
mounted in the head allow
rapid,
unobstructed
flow of fuel and air to the combustion chambers through short, water-jacketed intake passages.The
intake valves are operated by push rods through

rocker
arms. The exhaust valves are mounted

in
the block with through water jacketing to provide
effective
cooling. The exhaust valves are
operated by conventional valve tappets.
The
engine
is pressure lubricated. An oil pump

driven
from the camshaft forces the lubricant
through oil channels and drilled passages in the

crankshaft
to efficiently lubricate the main and
connecting rod bearings.
Lubricant
is also force
fed to the camshaft bearings, rocker arms, timing
gears, etc.
Cylinder
walls and piston pins are

lubricated
from spurt
holes
in the "follow" side of
the connecting rods.
Circulation
of the coolant is controlled by a
thermostat in the water
outlet
elbow cast as part
of the cylinder head.

The
cylinder head assembly when installed on the

engine
consists of the inlet valve guides, inlet valves, inlet valve springs, rocker arm and shaft assemblies, spark plugs, temperature indicator
fitting, water
outlet
fitting, and other assembled

parts.
The carburetor and air cleaner assembly
bolt to the top of the cylinder head. The rocker

arm
cover is attached to the top of the head to
enclose
the inlet valve mechanism.
The
engine
is equipped with a fully counterbalanced
crankshaft
supported by three main bearings. To better control balance, the counterweights are in­
dependently forged and permanently attached to
the crankshaft with dowels and cap screws that are tack-welded.
Crankshaft
end play is adjusted by
shims placed
between
the crankshaft thrust washer

and
the shoulder on the crankshaft.
The
exhaust manifold is a separate unit. The intake
manifold is cast as an integral part of the cylinder
head and is completely water jacketed.
This
con­
struction transfers heat from the cooling system
to the intake passages and assists in vaporizing
the fuel when the
engine
is cold. Therefore, there
is no heat control valve required in the exhaust manifold. Individual exhaust ports in the cylinder
block direct
gasses
into the exhaust manifold for unobstructed flow through the exhaust system.

The
pistons have an extra
groove
directly above
the top ring which acts as a heat dam or insulator.
As
is common practice with manufacturers,
some

engines
are built with oversize cylinder bores or undersize crankshaft journals. These
engines
are
considered standard as replacement parts of the

correct
sizes are supplied. Before ordering parts or
doing any work with a particular engine, it is important to check the
engine
code
number to
determine if oversize or undersize parts are re­

quired.
Definite identification is given by a letter
stamped after the
engine
code
number. See Fig.

A-5
for location. The letters used and their mean­ ings are given here:

A
— .010*
[0,254
mm.] undersize main and
connecting rod bearings.

B
— .010"
[0,254
mm.] oversize pistons.

AB
—
Combination
of A and B.

S
—
Service
engine.

R
—
Short
Block.
Detailed specifications for the
Hurricane
F4
engine

are
at the end of this section.
Torque
specifications
for
engine
service are at the end of this manual in Section U. When adjustments are necessary, refer to
these
specifications so that factory clearances

are
maintained.

D-3.
Engine Mountings

The
front of the
engine
is supported by two rubber
Text continued on
page
41. 38

'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

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