low oil pressure JEEP CJ 1953 Service Manual

B

LUBRICATION
B-2.
Special Lubricants

Special
lubricants are required for certain
lubri­
cation points on the 'Jeep' Universal vehicles. The

special
lubricants are necessary for proper function­ ing and maintenance of the vehicle. The
Lubrica­
tion
Chart
(Fig. B-l and B-2)
designates
the spe­
cial
lubricating points and identifies them by type

or
part number.

B-3.
Applying
Fresh
Lubricant

When
servicing or lubricating the vehicle, it is important that all old lubricant and
dirt
be re­ moved from the fitting and/or plugs before servic­
ing and that the recommended type of lubricant be used for the particular item being serviced.
Force
lubricant through the lube fittings until the lubricant being forced out of the joint is fresh

lubricant,
indicating that all old lubricant has
been removed.

B-4.
Engine
Lubrication
System —
Hurricane
F4 Engine

•
Refer to Fig. B-3.

The
engine
oil pressure system is designed to pro­
vide adequate lubrication to all working parts of
the engine. The gear-type oil pump is driven from
the
engine
camshaft. The pump is provided with a
FIG.
B-3—ENGINE
LUBRICATION
SYSTEM
—

HURRICANE
F4
ENGINE
floating, screened intake that prevents the
circula­

tion of any sediment that might accumulate in the

oil
pan. By means of this pump, the main bearing

journals
and crankpins are efficiently lubricated through an oil gallery and passages in the cylinder
block.
Oil
is forced under pressure to the main bear­
ings and through the cheeks of the crankshaft to
the connecting rod bearings. Oil is also force-fed
to the camshaft bearings, timing gears, and intake valve rocker arms. The oil pressure is controlled by

relief
valve located in the oil pump. The valve is
designed to open when excessive pressure
develops
in
the system, relieving the pressure and returning the
excess
oil to the oil pan. The cylinder walls,
piston pins, and tappets are supplied with oil from
spurt
holes
in the connecting rods. A portion of the oil is continually passed through an oil filter
which
effectively removes any foreign matter sus­ pended in the oil. A flanged section on the
rear
of
the crankshaft acts as an oil slinger and, in com­
bination with the
rear
main bearing upper and lower oil seal, prevents the leakage of oil from the

rear
end of the cylinder block. Leakage of oil from
the front end of the cylinder block is controlled by the crankshaft oil slinger and the front oil seal
installed in the timing gear cover. The oil pressure
indicator
light in the instrument panel and the oil level
gauge
or dip stick in the side of the
engine

provide a means for checking the oil pressure and

oil
level.

B-5.
Oil Pressure Gauge or Indicator
On
early
CJ-3B
vehicles an oil pressure
gauge
is
mounted on the instrument panel.
This
gauge
in­ dicates the oil pressure within the
engine
lubri­

cating system.

On
Models
CJ-5,
CJ-5A,
CJ-6,
CJ-6A,
DJ-5, DJ-6

and
later production vehicles of Model
CJ-3B
a
red
telltale lamp, which operates when the ignition
switch is turned on, is lit when there is insufficient
oil
pressure to properly lubricate the engine. When

it
goes
out, operating pressure is achieved. In
normal
operation, the light is lit when the ignition
is first turned on. It
goes
out after the vehicle is

in
motion.

Failure
of the
gauge
or indicator to register normal
oil
pressure may indicate insufficient supply of oil

in
the
engine
crankcase, low or no oil pump pres­
sure,
or a fault in the
gauge
or indicator electrical

circuit.
The
engine
must be stopped immediately to prevent possible damage to
engine
bearings and
the fault corrected before restarting the engine.

B-6.
Engine
Lubrication
System — Dauntless V-6 Engine

The
engine
lubrication system (Fig. B-4) is the
force
feed
type in which oil is supplied under pres­

sure
to the crankshaft, connecting rods, camshaft bearings and valve lifters. Oil is supplied under con­trolled volume to the rocker arm bearings and push

rods.
All other moving parts are lubricated by gravity flow or splash.

The
supply of oil is
carried
in the oil pan which is filled through a filter opening in the right rocker

arm
cover. A removable oil
gauge
rod on the left side of the crankcase is provided to check oil level.

The
oil pump is located in the timing chain cover 10

'Jeep*
UNIVERSAL
SERIES
SERVICE
MANUAL

13330

FIG.
B-4—ENGINE
LUBRICATION
SYSTEM
—
DAUNTLESS
V-6
ENGINE

1—
Rocker
Arm Shaft
2—
Main
Oil
Line

3—
Oil
Inlet where it is connected by a drilled passage in the

cylinder
crankcase to an oil screen housing and
pipe assembly. The screen is submerged in the oil supply and has ample area for all operating condi­
tions. If the screen should
become
clogged
for any reason, oil may be drawn into the system over the
top
edge
of the screen, which is held clear of the

sheet
metal screen housing.

Oil
is drawn into the pump through the screen and
pipe assembly and a drilled passage in the
crank­

case, which connects to drilled passages in the
timing chain cover. All oil is discharged from the
pump to the oil pump cover assembly. The cover
assembly consists of an oil pressure relief valve,
an
oil filter bypass valve and a nipple for installa­
tion of an oil filter. The spring loaded oil pressure

relief
valve limits the oil pressure to a maximum
of 30 pounds [13.607 kg.] per square inch. The

oil
filter bypass valve
opens
when the filter has
become
clogged
to the
extent
that
4V2
to 5 pounds [2.04 a 2.27 kg.] pressure difference exists
between

the filter inlet and exhaust to bypass the oil filter
and
channel unfiltered oil directly to the main oil galleries of the engine.

A
full flow oil filter is externally mounted to the

oil
filter cover nipple on the right side of the en­ gine, just below the alternator. Normally, all
engine

oil
passes through the filter element; however, if
the element
becomes
restricted, a spring loaded bypass valve
opens
as mentioned above. The main

oil
galleries run the full length of the crankcase
and
cut into the valve lifter guide
holes
to supply

oil
at full pressure to the lifters. Connecting pas­
sages
drilled in the crankcase permit delivery of

oil
at full pressure to all crankshaft and camshaft
bearings.
Holes drilled in the crankshaft
carry
oil from the
crankshaft
bearings to the connecting rod bearings.
Pistons and cylinder walls are lubricated by oil
forced through a small notch in the bearing parting
surface on the connecting rod, which registers with
the
hole
in the crankpin
once
in every revolution. Piston pins are lubricated by splash.

Drilled
holes
in the camshaft connect the front camshaft bearing
journal
to the key slot in the front
of the camshaft. Oil flows from the
journal
into
the keyslot over the woodruff key in the space

between
the key and the camshaft sprocket and fuel pump eccentric.

The
forward end of the fuel pump eccentric in­ corporates a relief which allows the oil to escape

between
the fuel pump eccentric and the camshaft

distributor
gear. The oil stream strikes the distri­
butor shaft gear
once
each camshaft revolution, and provides ample lubrication of the timing chain and
sprockets by splash.

The
rocker arms and valves on each cylinder head

are
supplied with oil from the oil galleries through

holes
drilled in the front of the cylinder block and

cylinder
head. The
hole
drilled in the cylinder
head ends beneath the front rocker
arm
shaft brack­ et. A notch cast in the base of the rocker arm shaft

bracket
allows the oil to flow up inside the bracket

in
the space
between
the bracket and bolt, to the
hollow rocker arm shaft which is plugged at both
ends.
Each
rocker arm receives oil through a
hole

in
the underside of the shaft. Grooves in the rocker

arm
provide lubrication of the bearing surface. Oil
is metered to the push rod seat and valve stem
through
holes
drilled in the rocker arm. Excess
oil
drains off and returns to the oil pan through
passages in the cylinder head and block. Refer to
the
Lubrication
Chart
for lubrication frequency and

lubrication
type and grade.

B-7.
Chassis
Lubrication

Chassis
and
engine
should be serviced at periodic
intervals.
Most chassis lubricating points, whether
long-life or conventional, have standard lubrication
fittings. Refer to the
Lubrication
Specifications and

Service
Maintenance Schedule for specific points

and
lubricating time intervals. It is not necessary
to disassemble prepacked joints to lubricate them.

Merely
add new lubricant, as described in Par.
B-3,
to remove all old lubricant.

At
the appropriate interval, clean each lubrication
fitting indicated on the Lubrication
Chart
and
Service
Maintenance Schedule. Use a pressure gun
to lubricate. Be sure the grease channels are open
to provide complete lubrication of bearing surfaces.
In
some
cases it may be necessary to disassemble
to clear plugged channels.

When
vehicles are driven primarily in abnormally dusty or wet areas or when a vehicle is subject to
severe operating conditions, perform
these
services
more frequently. Under
these
conditions, no definite interval can be recommended because of the great variety of
uses
and conditions of use. 11

LUBRICATION

vital
to the life of the
engine.
When the vehicle
is operated under abnormal conditions, (for ex­
ample when driven on secondary roads or through
fields) then service of the air cleaner must be more frequent

Note:
Under extreme continually dusty and dirty
conditions where the vehicle operates in clouds of dust and
dirt,
service the air cleaner daily.

a.
To service the air cleaner on vehicles equipped
with the
Hurricane
F4
engine
(Fig. B-5) unscrew
the eye
bolt
on the oil cup clamp and remove the

oil
cup from the cleaner body. Remove the oil from the cup and scrape all
dirt
from the inside, wash cup clean using a cleaning solution if neces­

sary.
In summer
refill
the oil cup with IV2 pints [0,6 ltrs.] of
SAE-40
or 50 grade
engine
oil. In
winter
refill
using grade
SAE-20
engine
oil. For
servicing the air cleaner
body
(less
oil cup),
loosen

hose
clamp and remove
hose
from the cleaner. Detach breather
hose
from the fitting on the cleaner. Remove the two wing screws and lift the
cleaner from the vehicle. Agitate the cleaner
body

thoroughly in cleaning solution to clean the filtering

element.
Dry
element
with low pressure com­ pressed air. Reinstall the cleaner
body
and replace
the oil cup. Service the air cleaner every
2000
miles
[3.200
km.].
b. To service the oil bath air cleaner on vehicle
equipped with the Dauntless V-6
engine
(Fig. B-6),

first
remove the air cleaner from the carburetor
by unscrewing the wing nut. Remove the oil cup
FIG.
B-5—OIL
BATH AIR
CLEANER
-
HURRICANE F4 ENGINE 1—
Horn
7—Clamp
2—
Flexible
Connector
8—Oil
Cup
3—
Hon
Clamp
9—Clamp

A—Carburetor
Vent Tube 10—Hose 5— Body 11—Clamp
6—
Screw
and
Lock
Washer 13—Gasket
FIG.

B-6—OIL BATH AIR
CLEANER
-
DAUNTLESS V-6 ENGINE

1—WinB
Nut
2—
Cover

3—
Rubber
Gasket
4—
Cork
Gasket
5—
Oil
Cup 6—
Breather

7—
Clamp

8—
Vent
Tube 9—
Air
Pump Hose from cleaner
body
and remove the oil from the cup,
scrape all
dirt
from the inside.
Clean
oil cup thor­
oughly, wash filter
element
in a solvent that
will
leave it clean and dry.
Fill
oil cup to indicated
level with clean
S.A.E.
40 or 50 grade
engine
oil
(S.A.E.
20 grade in winter.) Assemble cleaner filter

element
to oil cup making sure that gasket is in
place
between
the two pieces. Assemble air cleaner assembly to carburetor making sure the gasket
be­

tween
air cleaner and carburetor is in place. Secure

air
cleaner to carburetor with wing nut. Service the

air
cleaner every
6000
miles
[9.600
km.],
c.
Carefully
check the
hose
clamps and
fittings
on
the breather
hoses
at frequent intervals. Loose con­nections
will
affect proper operation of the
crank­

case ventilating system.

B-26. Dry-Type
Air Cleaner Service the air cleaner on Dauntless V-6
engines

at each oil change under normal driving conditions.

If
the vehicle is operated under dusty conditions,
check the condition of the air cleaner
element
more
frequently and service if dirty.

Servicing
the air cleaner consists of cleaning or replacing the air cleaner
element
and replacing the

crankcase
ventilation filter (breather assembly). See Fig. B-7.

The
air cleaner
element
assembly consists of a
paper
element
and a polyurethane
element
The
paper
element
cannot be cleaned.

To
clean the polyurethane
element,
first carefullly remove it from the paper
element
Then
wash it in 14

B

LUBRICATION
B-72.
Powr-Lok
or Trac-Lok
Differential

Refer
to Par. B-53.

B-73.
PARTS
REQUIRING
NO
LUBRICATION

B-74.
Water Pump Bearing,
Clutch
Release
Bearing

The
water pump and clutch release bearings are

prelubricated
for life when manufactured and cannot be relubricated.

B-7S.
Starter
Motor
Bearings

The
starting motor bearings are lubricated at assembly to last
between
normal rebuild periods.

B-76.
Alternator Bearings

The
alternator bearings are lubricated at assembly

and
require no further lubrication.

B-77.
Springs

The
vehicle springs should not be lubricated. At assembly the leaves are coated with a long-lasting

special
lubricant which is designed to last the life
of the springs. Spraying with the usual mixture of
oil
and kerosene has a tendency to wash this
lubri­

cant
from
between
the leaves, making it necessary
to relubricate
often
to eliminate squeaking.

B-78.
Shock Absorbers

Hydraulic
direct-action shock absorbers are per­ manently sealed and require no periodic
lubrica­

tion service. Shock absorber mounting bushings
are
not to be lubricated.

B-79.
LUBRICATION
REQUIREMENTS
FOR
OFF-HIGHWAY
OPERATION

Adequate lubrication
becomes
increasingly im­ portant when vehicles are used in off-highway
operation. Under
these
conditions all operating
parts
of both the
engine
and chassis are subjected
to unusual pressures. At the same time such operation is usually under abnormal dust and
dirt

conditions making additional precautions neces­

sary.
The importance of correct lubrication for
the conditions of operation cannot be overestimated.

B-80.
Engine
Oil

It
is important, that the oil in a new or rebuilt
engine
be changed after the first
eight
or ten hours
of operation, and for heavy, dusty work, every 50

hours
thereafter. Watch the condition of the oil closely and change it immediately if it appears to
be contaminated.

i-Il.
Engine
Oil
Filter

Replace
the oil filter at the end of the first 100

hours
of service. Under extreme operating con­ ditions, more frequent replacement may be re­
quired.
The condition of the oil is a reliable

indicator
of the condition of the filter element.
If
the oil
becomes
discolored and shows evidence
of contamination, change the filter without delay.
(Refer
to
Par.
B-10, B-ll for the correct procedure
for replacing the oil filter.)

B-82.
Air Cleaner

Care
of the air cleaner is extremely vital to the life of the engine. Pay particular attention to the
amount of dust and
dirt
in the air taken into the

engine
through the air cleaner. When dust is not
noticeable in the air, service the air cleaner each scheduled maintenance period. Whenever the air is
noticeably dusty (for example when the vehicle is

driven
on secondary roads or through fields) then
service the air cleaner more frequently. Under extreme continually dusty and dirty conditions
where the vehicle operates in clouds of dust and

dirt,
service the air cleaner daily. (Refer to Par.
B-24
thru
B-26 for service procedures.)

B-83.
Chassis
Lubrication

The
period of lubrication depends entirely upon the type of work being done. Using the specified

interval
given in the Service Maintenance Schedule as a guide, lubricate at safe intervals required for
the particular type of operation. Under extremely
dusty conditions lubricate
these
points daily. Be

sure
to force enough lubricant into each fitting to force out the old lubricant which might be con­
taminated with grit and which would cause
rapid

wear
if allowed to remain.
Do not place lubricant on the various
ball
and socket joints or pivot points of the lift linkage as
dirt
will
accumulate to form an abrasive mix­

ture.
It is
best
to simply wipe
these
parts clean

with
a cloth.

B-84.
Front
Axle
Shaft Universal Joints

For
off-highway use remove the universal joints twice yearly, thoroughly clean both the housings

and
joints with a suitable solvent, and
refill
the
housings to the
fill
plug opening levels with the

correct
lubricant as given in the
Lubrication
Specifications.

B-85.
Transmission and Transfer
Case

The
combined capacity of the two housings is
small
for economy, making it important that the

lubricant
be changed at regular intervals. For off-highway use
drain
both housings every 300

hours
of operation and
refill
to the
fill
plug opening
levels. Refer to B-35 through B-37 when changing

lubricant.

B-86.
Front and
Rear
Axle
Differentials

Because of the higher pressure developed in the
axle assemblies with heavy duty operation,
drain,

flush,
and
refill
the differential assemblies each 300 hours of operation. Use only flushing oil or light
engine
oil to clean out the housings (except

Powr-Lok
and
Trac-Lok
differentials). Refer to
Par.
B-52 and B-53 for draining and flushing

differential.
18

c

TUNE-UP

14011

FIG.
C-8—POSITIVE CRANKCASE VENTILATION VALVE
vacuum
hose
and insert a stiff wire into the valve
body and observe whether or not the plunger can be readily moved (Fig. C-8). The valve may be
cleaned, by soaking in a reliable carburetor clean­
ing solution and drying with low pressure dry air.
b.
Hurricane
F4 Engine.

Ventilation
of the
Hurricane
F4
engine
is accom­
plished in the same manner as the Dauntless V-6

engine
described above, the differences being that clean air enters the crankcase through a
hose
con­ nected
between
the top cover of the air cleaner and
the oil filler tube of the engine. The ventilation valve is screwed to a pipe fitting mounted in the
center of the intake manifold
between
number two

and
three cylinder inlet. A
hose
connects the venti­
lation valve to a vapor
dome
on the rocker arm
cover. Service procedures are the same as
those

used on the Dauntless V-6 engine. The valve may be checked for vacuum
pull
by removing the
hose

from
the valve while running the
engine
at fast idle speed and placing a finger on the valve opening to
check the vacuum. (Refer to Fig. C-9).

C-7.
Service
Manifold
Heat
Control
Valve
The
Dauntless V-6
engine
is equipped with a mani­fold heat control valve (Fig. F-6). Test the valve
for free operation. Place a few drops of penetrating

oil
at each end of the shaft where it passes through
the manifold.
Then
move
the valve up and down

a
few times to work the oil into the bushing. When
the
engine
is cold, the valve should be in the closed
position to ensure a fast warm-up of the intake
manifold for better fuel vaporization. When the
valve is closed, the counterweight is in its counter­ clockwise position. As the
engine
warms the coun­
terweight slowly rotates clockwise until the valve is fully open.

C-8.
Check
Valve
Tappet
Clearance
a.
Hurricane
F4 Engine.

With
the
engine
cold, check and adjust the intake
valve to .018"
[0,460
mm.] clearance and the ex­
haust valves to .016" [0,406 mm.] clearance. The
intake valves are adjusted by removing the rocker

arm
cover mounted on the cylinder head.
Turn
the
engine
over until No. 1 cylinder piston is on top
dead center on its compression stroke, then using a
feeler
gauge
check the clearance
between
the valve stem and the toe of the rocker arm. If clearance is

less
or greater than .018"
[0,460
mm.] the valve
must be adjusted by turning the rocker arm nut
clockwise to decrease and counterclockwise to in­ crease the clearance. When No. 1 cylinder intake
valve has been properly set use the same proce­
dures to check and reset, if necessary, the remaining
three cylinder valves. The exhaust valves are ad­ justed by removing the tappet cover located on
the right side of the engine. Place the cylinder to
be adjusted on top dead center (compression stroke) and check the clearance
between
the valve stem and tappet screw with a feeler
gauge.
If the
clearance is
less
or greater than .016" [0,406 mm.]
the valve must be adjusted by loosening the tappet
screw locknut and turning the screw until the proper clearance is obtained, then tighten the lock-
nut.

Note:
Always recheck the valve clearance after
tightening the locknut.
b. Dauntless V-6 Engine.

The
valve tappet clearance of the Dauntless V-6

engine
needs
no adjustment as the lifters are

hydraulic
and require no lash adjustment at time
of assembly or while in service.

C-9.
Check
Engine
Cylinder
Compression
a.
Hurricane
F4 Engine.

To
take the compression readings of the
engine
cylinders
remove all the
spark
plugs and disconnect
the high tension wire from the coil.
With
the throttle and choke open
turn
the
engine
with the

starter
motor while firmly holding the compression
gauge
in the
spark
plug port of the cylinder to be
checked. Allow at least four compression strokes
when checking each cylinder and record the first
and
fourth stroke reading of the
gauge.

When
pressure quickly
comes
up to specified pres­

sure
and is uniform
between
all cylinders within 10 psi. [0,7 kg-cm2] it indicates that the
engine
is
operating normally with satisfactory seating of

rings,
valves, valve timing, etc.
When
pressure is low on the first stroke and builds
up to
less
than specified pressure it indicates com­
pression leakage usually attributable to rings or
valves. To determine which is responsible, pour
Vz
oz. [15 cm3] of tune-up oil into each cylinder.

Allow
a few minutes for the oil to leak down past
the rings and then again
test
compression. If com­
pression pressures improve over the first
test,
the trouble is probably worn piston rings and bores. If
compression pressures do not improve, the trouble
is probably caused by improper valve seating. If
this condition is noticed on only two cylinders that
are adjacent, it indicates that there is a possible gasket leak
between
these
cylinders. If inspection
of the
spark
plugs from
these
cylinders disclosed
fouling or surface cracking of electrodes, gasket leakage is probable.

When
pressure is higher than normal it indicates
that carbon
deposits
in the combustion chamber have reduced the side of the chamber enough to
give
the
effect
of a raised compression ratio.
This

will
usually cause a pinging sound in the
engine
when under load that cannot be satisfactorily cor­rected by timing. The carbon must be cleaned out
of the
engine
cylinders to correct this trouble.

Reinstall
the
spark
plugs. Torque with a wrench
to proper setting.

Advise
the vehicle owner if compression is not satisfactory. 24

'Jeep*
UNIVERSAL SERIES SERVICE
MANUAL

COMPRESSION PRESSURE LIMIT CHART

Maximum
Pressure
Minimum

Pressure
Maximum

Pressure
Minimum

Pressure

psi.
kg-cm2
psi.
kg-cm2
psi.

kg-cm2

psi.

kg-cm2

134 9,42 101 7,10
188
13,22 141
9,91
136 9,56 102 7,17 190
13,36 142
9,98
138 9,70 104 7,31 192
13,50 144 10,12
140 9,84 105 7,38 194
13,64 145
10,19
142 9,98 107 7,52 196
13,78 147 10,33
144 10,12 108 7,59 198
13,92
148 10,40
146 10,26 110 7,73 200
14,06 150 10,55
148 10,40 111 7,80
202
14,20 151
10,62
150 10,55 113 7,94 204
14,34 153
10,76
152 10,68 114 8,01 206
14,48 154 10,83
154 10,83
115 8,08 208
14,62 156
10,97
156 10,97 117 8,23
210
14,76 157 11,04
158 11,11 118 8,30 212
14,90
158 11,11
160 11,25 120
8,44 214
15,04 160
11,25
162 11,39 121 8,51 216
15,18 162 11,39
164 11,53
123 8,65 218
15,32 163
11,46
166 11,67 124 8,72 220
15,46 165 11,60
168 11,81 126 8,86 222
15,61 166
11,67
170 11,95 127 9,83 224
15,75 168 11,81
172 12,09 129 9,07 226
15,89 169
11,88
174 12,23 131 9,21 228
16,03 171 12,02
176 12,37 132 9,28 230
16,17 172
12,09
178 12,51 133 9,35 232
16,31
174 12,23
180 12,65 135 9,49
234
16,45 175 12,30
182 12,79 136 9,56 236
16,59 177 12,44
184 12,94 138 9,70
238
16,73 178 12,51
186 13,08 140 9,84
b.
Dauntless V-6 Engine.

To
check the
engine
cylinder compression use the
following procedures:

Firmly
insert compression
gauge
in
spark
plug
port
(Fig.
C-10).
Crank
engine
through at least four
compression strokes to obtain highest possible

reading.

Check
compression of each cylinder. Repeat com­
pression check and record highest reading obtained on each cylinder during the two pressure checks.

Note:
The recorded compression pressures are to
be considered normal if the lowest reading cylinder
is more than seventy-five percent of the highest

reading
cylinder. See the following example and
the "Compression Pressure
Limit
Chart".
Example:

Cylinder
No. 1 2 3 4 5 6

Pressure
(psi.) 129 135 140 121 120 100
Seventy-five percent of 140 (highest) is 105.
Thus,

Cylinder
No. 6 is
less
than seventy-five percent
of
Cylinder
No. 3.
This
condition, accompanied by low speed missing, indicates an improperly seated
valve or worn or broken piston
ring.

If
one or more cylinders read low, inject about

a
tablespoon of
engine
oil on top of pistons in low

reading
cylinders through
spark
plug port. Repeat compression check on
these
cylinders.

If
compression improves considerably, rings are

worn.
If compression
does
not improve, valves are

sticking
or seating poorly.

If
two adjacent cylinders indicate low compression

and
injecting oil
does
not increase compression, the
cause may be a head gasket leak
between
the

cylinders.
Engine coolant and/or oil in cylinders could result from this
defect.
FIG.
C-10—CHECKING ENGINE CYLINDER
COMPRESSION
—
DAUNTLESS
V-6
ENGINE
FIG.
C-l
1—CONTACT
POINTS
MATERIAL
TRANSFER

25

c

TUNE-UP
C-10.
Distributor
Service

The
distributor cap should be inspected for
cracks,

carbon runners and evidence of arcing. If any
of
these
conditions exists, the cap should be re­
placed.
Clean
any corroded high tension terminals. Inspect the rotor for cracks or evidence of
exces­

sive burning at the end of the metal strip. After

a
distributor rotor has had normal use the end
of the rotor
will
become
burned. If burning is found
on top of the rotor it indicates the rotor is too
short and
needs
replacing. Usually when this con­
dition is found the distributor cap
segment
will

be burned on the horizontal face and the cap
will

also need replacing.
Check
the condenser lead for broken wires or

frayed
insulation.
Clean
and tighten the connec­
tions
on the terminal
posts.
Be sure the condenser
is mounted firmly on the distributor for a
good
ground connection. Should a condenser tester be available the capacity
should be checked. In the absence of a tester check
by substituting a new condenser.
Examine
the distributor
points
(Fig.
C-ll).
If
they

show wear, poor mating, transferred metal, or pitting, then new
ones
should be installed.
Clean

the
points
with a suitable solvent and a stiff
bristled brush.
Check
the alignment of the point for a
full,
square
contact. If not correctly aligned, bend the station­
ary
contact bracket slightly to provide alignment,

a.
Hurricane F4 Engine (Prestolite).

The
contact gap of the distributor point on the

Hurricane
F4
engine
should be set at .020"
[0,508

mm.],
measured with a wire
gauge.
Adjustment of
the gap is accomplished by
loosening
the lock screw and turning adjusting eccentric screw (Fig.
C-12)
until correct gap is secured. Be sure that the
fiber block on the breaker arm is resting on the
highest point on the cam while the adjustment is being made. Recheck the gap after locking the
adjustment.

Apply
a thin film of cam lubricant to the cam to
lessen fiber block wear. Should a condenser tester be available the capacity
should check from .21 to .25 microfarads. In the
absence of a tester check by substituting a new
condenser.

Check
point contact spring pressure, which should
be
between
17 and 20
ounces
[0,487
a 0,56 kg.].
Check
with a spring scale hooked on the breaker

arm
at the contact and pull at right
angle
to the

breaker
arm. Make the reading just as the
points

separate. Adjust the point pressure by
loosening
the stud holding the end of the contact arm spring

and
slide the end of the spring in or out as neces­

sary.
Retighten the stud and recheck the pressure. Too low a pressure
will
cause
engine
missing at
high
speeds.
Too high a pressure
will
cause rapid wear of the cam, block, and points.
b. Dauntless V-6 Engine (Delco).

The
spark advance is fully automatic being con­
trolled by built-in centrifugal weights, and by a vacuum advance system (Fig.
C-13).
The same
checking procedures are used as (a)
above
except,

the capacity of the condenser must be .18 to .23 microfarads and the contact gap should be set at
.016"
[0,406
mm.]. Adjustment of the gap is made
by rotating the socket head adjustment screw with
a
Vs" [3,86 mm.] Allen wrench (Fig.
C-14).

The
contact spring pressure must be 19 to 23 ozs.
[0,538
a
0,652
gr.] and the cam dwell
angle
is

30°,
with distributor vacuum line disconnected.
The
preferred method of adjusting cam dwell re­
quires turning of the adjusting screw until the specific dwell
angle
is obtained as measured by a
dwell
angle
meter. Refer to Par. C-l7. To adjust
the cam dwell by an alternate method, turn the adjusting screw in (clockwise) until the
engine

FIG.
C-12—PRESTOLITE DISTRIBUTOR HURRICANE F4 ENGINE
1— Condenser
2—
Lubricating
Wick

3—
Breaker
Cam
4—
Breaker
Arm Pivot 5—
Distributor
Cap (Rotation &
Firing
Order)
6—
Distributor
Points 7— Adjustment
Lock
Screw
8—
Adjusting
Eccentric
Screw
9—
Oiler

10—Primary
Wire
26

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

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