
'Jeep*
UNIVERSAL
SERIES SERVICE
MANUAL
Dl
12713
FIG.
Dl-11—MEASURING
TELESCOPE GAUGE
1—
Telescope
Gauge
2—
Micrometer
may
be measured with an inside micrometer or
by setting the cylinder
gauge
dial
at zero and meas
uring
across the
gauge
contact points with an outside micrometer while the
gauge
is at same zero
setting. Refer to
Figs.
Dl-10 and Dl-11.
b.
If a cylinder bore is moderately rough or slightly
scored,
but is not out-of-round or tapered, it is
usually
possible to remedy the situation by honing
the bore to fit a standard service piston, since
standard
service pistons are high-limit production
pistons. If cylinder bore is very rough or deeply
scored,
it may be necessary to rebore the cylinder
to fit an oversize piston in order to ensure satisfac
tory
results.
c.
If cylinder bore is tapered .005" [0,127 mm.]
or
more or is out-of-round .003" [0,076 mm.] or
more,
it is advisable to rebore for the smallest possible oversize piston and rings.
d.
Carefully
inspect the cylinder block for small
cracks
or fractures, and for porosity.
Rust
in any
cylinder
bore may indicate a leak.
e.
Inspect all machined surfaces for scoring and
burrs.
With
a straight
edge
and feeler
gauge,
check
each
machined surface for distortion.
D1-37.
Cylinder Block Repair
If
one or more cylinder bores are rough, scored, or
worn
beyond prescribed limits, it
will
be necessary
to correct bores and fit new pistons.
If
relatively few bores require correction, it
will
not be necessary to rebore all cylinders to the same
oversize in order to maintain
engine
balance, since
all
oversize pistons are held to the same weights as
standard-size
pistons. If conditions justify replace
ment of all pistons, however, all new pistons should
be the same nominal size.
Standard-size
service pistons are high-limit, or
maximum
diameter; therefore, they can usually be installed after a slight amount of honing has
been
done
to correct slight scoring or excessive
clearances.
This
applies
primarily
to
engines
which
have relatively low mileage. Service pistons are also furnished in .010"
[0,254
mm.] oversize. All
service
pistons are diamond bored, and selectively
fitted with piston pins; pistons are not furnished
without pins.
Caution:
Do not attempt to cut down oversize pis
tons
to fit cylinder bores as this
will
destroy the
surface
treatment and affect the weight. The small
est possible oversize service pistons should be used
and
the cylinder bores should be honed to size
for
proper clearance.
Before
honing or reboring cylinders, measure all new pistons with a micrometer, on an axis perpen
dicular
to the piston pin. Select the smallest piston
for
the first fitting. The slight variation usually
found between pistons in a set may provide for
correction
in case the first piston tried is too
small.
If
wear at top of cylinder
does
not exceed .005" [0,127 mm.]
excess
diameter, or exceed .003"
[0,076 mm.] out-of-round, honing is recommended.
If
wear or out-of-round
exceeds
these
limits, the
bore should be reground with a boring bar of the
fly
cutter type, then finish-honed.
When
reboring cylinders, all crankshaft bearing caps must be in place and tightened to proper
torque to avoid distortion of bores in
final
assem
bly.
Always be sure the crankshaft is out of the
way
of the boring cutter when boring each cylinder.
When
boring, leave the diameter .001" [0,025 mm.]
undersize,
then finish hone to obtain the required
clearance.
When
honing cylinders, use clean sharp
stones
of
proper
grade for the amount of metal to be re
moved. Refer to instructions supplied by the hone
manufacturer.
Dull
or dirty
stones
cut unevenly
and
generate excessive heat. When using coarse
or
medium grade
stones,
leave sufficient metal so
that all
stone
marks can be removed with the fine
stones
used to finish-hone to proper clearance.
When
finish-honing, pass the hone through the entire length of cylinder at a rate of approximately 60 cycles per minute.
This
should produce the
desired
45-degree
cross hatch pattern on cylinder
walls.
A proper pattern
will
ensure maximum
ring
life and minimum oil consumption.
After
final
honing and before the piston is checked
for
fit, each cylinder bore must be washed thor oughly to remove all traces of abrasive, then dried completely. The dry bore should be brushed clean
with
a power-driven fibre
brush.
If all traces of
abrasive
are not removed,
rapid
wear of new pistons
and
rings
will
result.
Note:
Wipe cylinder bores with a clean white
cloth,
moistened with SAE 10 oil. Cleaning should
continue until this
test
shows no sign of
dirt.
It
is of the greatest importance that refinished
cylinder
bores be true, with .0005" [0,013 mm.]
or
less out-of-round or taper.
Each
bore must have
a
smooth surface, without
stone
or cutter
marks.
After
final
honing and cleaning, each piston must be fitted individually to the bore in which it
will
be installed. Once fitted, each piston should be
marked
with its cylinder number to assure correct
installation.
85

Dl
DAUNTLESS
V-6
ENGINE
Note:
During
engine
reassembly, use Perfect Seal
Aerosol
Spray Sealer
Part
No.
994757
on all en
gine
gaskets to ensure against vacuum, oil, gasoline
and
water leaks. Apply to head gaskets, valve covers, water pumps, oil pan gaskets, radiator and
heater
hose
connections, felt gaskets, gasoline and
oil
line connections, stud bolts, spark plug threads,
and
grease retainer washers. Refer to manufac
turer's
instructions on container for proper appli
cation procedure.
Dl-72.
Cylinder
Block
and Crankshaft
Rear
Oil Seals
Braided
fabric seals are pressed into
grooves
of
cylinder
block and
rear
main bearing cap, to
rear
of the oil collecting groove, to seal against oil leak age at the crankshaft. Refer to Fig. Dl-32.
FIG.
Dl-32—INSTALLING
CRANKSHAFT REAR
OIL
SEAL
1—Neoprene
Seal
2—Fabric
Seal
A
neoprene composition (stick) seal is installed in
grooves
in the sides of the
rear
main bearing cap
to seal against leakage in the joints
between
the
cap and cylinder block. The neoprene composition
expands in the presence of oil and heat.
This
seal
is undersize when newly installed. Refer to Fig.
Dl-32.
a.
The braided fabric seal can be installed in the
cylinder
block only when the crankshaft is re moved; however, the seal in the cap can be replaced
whenever the cap is removed. Remove oil seal and place new seal in groove, with both ends projecting
above parting surface of cap. Force seal into
groove
by rubbing down with hammer handle or smooth
stick
until seal projects above the
groove
not more
than
[1,59 mm.]. Cut ends off flush with
sur
face of cap, using sharp knife or razor blade.
Lubricate
the seal with heavy
engine
oil just before
installation.
Caution:
The
engine
must be operated at slow
speed when first started after new braided seal
has been installed.
b. The neoprene composition seal is slightly longer
than
the
grooves
in the bearing cap. The seal must
not be cut to length. The seals are installed after the bearing cap is installed in the block and torqued
firmly
in place. Dip the neoprene seals in kerosene
approximately IV2 minutes, then install seals into
bearing cap grooves. The protruding ends of the seals are, again, squirted with kerosene, wiped off,
and
peaned over with a hammer to be sure of a
seal
at the upper parting line
between
the cap and
cylinder
block.
Dl-73.
Main
Bearing and Crankshaft
Installation
Refer
to Fig. Dl-6.
This
procedure assumes that crankshaft main bear
ings have been inspected and proven satisfactory,
or
that new crankshaft main bearings of appropriate size have been selected. If necessary, check or select
main
bearings as described in Par. Dl-41 and
Pars.
Dl-42 and Dl-43.
a.
Install
four upper main bearing halves in
seats
of cylinder block so that prong of each bearing half
fits into corresponding notch of seat. Flanged thrust
bearing must be installed in the second seat from
front of engine.
Install
a new upper crankshaft
rear
oil seal in the cylinder block as described in
Par.
Dl-72.
Caution:
Upper main bearing halves have an oil groove, while lower halves are plain. They must
not be interchanged.
b. Apply
engine
oil to upper bearing surfaces.
Install
the crankshaft so that its four journals rest
in
the upper bearing halves.
c. Seat all four lower main bearing halves in cor
responding bearing caps.
Install
a new lower
crank
shaft
rear
oil seal and cylinder block
rear
oil seal
described in
Par.
Dl-72, a and b.
Lubricate
all lower
main
bearing surfaces with
engine
oil. Position bear ing caps to cylinder block and crankcase journals.
Install
two cap bolts,
loosely,
at each cap.
d.
It is necessary to align thrust surfaces of the
second main bearing whenever it has been removed
from
the engine. To do this, pry the crankshaft
back
and forth several times, throughout its entire end travel, with cap
bolts
of second main bearing
only finger tight.
e. Tighten alternate cap
bolts
of each main bearing
cap,
a little at a time, until they have been tight ened to 80 to 110 lb-ft. [11,1 a 15,2 kg-m.] torque.
D1-74. Crankshaft End Play Check
To
measure crankshaft end play, mount a dial
indicator
on the cylinder block and index its plung
er
to either a front or
rear
face of one crankshaft
counterweight. Pry the crankshaft to one limit
of its end travel and adjust the dial indicator to
zero. Pry the crankshaft to its
opposite
end travel
limit
and
note
end play as indicated by the dial
indicator.
Crankshaft end play tolerances are .004"
to .008" [0,102 a
0,204
mm.]. If end play is too great, it can be corrected only by replacement of
the second main (thrust) bearing.
Dl-75.
Piston and Connecting Rod
Installation
This
procedure assumes that connecting rod bear ings have been inspected and proven satisfactory,
or
that new connecting rod bearings of appropriate 96

FUEL
SYSTEM
14261
FIG.
E-6—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
1
2—Idle Mixture
Limiter
Cap
13—
Idle
Speed Adjusting Screw 14—
Fast
Idle Connecting Rod
E-11.
Float System
The
float system, Fig. E-7, consists of a float,
float
pin,
air horn gasket and the
needle
and seat assembly. These parts control the fuel level in the
carburetor
bowl, a supply being maintained for all
systems under all operating conditions. To prevent
float
vibration
from affecting the fuel level, the
inlet or float valve is spring loaded. Should the
needle
and seat
become
worn, they must be re
placed
with a matched set, including the spring,
which
is the only way they are supplied. When
reinstalling
the float, be sure to install the float pin
with
the
stop
shoulder on the side away from the bore of the carburetor.
E-12.
Float Adjustment
Correct
float level setting is required for accurate
metering of fuel in both low- and high-speed jets.
To
set the float, remove and invert the bowl cover. Remove the bowl cover gasket. Allow the weight
of the float to rest on the
needle
and spring. Be
sure
there is no compression of the spring other
than
the weight of the float. Adjust the level by
bending the float arm lip that contacts the
needle
(not the arm) to provide specified clearance be
tween the float and cover. The specified clearance of the float is
L74\F
[6,74 mm.] on current models
(including
Exhaust
Emission Control) and [7,93 mm.] on early models shown as A in
Fig.
E-8.
FIG.
E-7—FLOAT SYSTEM
1—
Float
and
Lever
Assembly
2—
Needle
Valve and Seat Assembly
3—
Vent
4—
Float
Bowl Cover 5—
Float
7 '.. j
io8Si
i
FIG.
E-8—FLOAT
LEVEL
GAUGING
E-13.
Low-Speed System
Fuel
for idle and early part-throttle operation is
metered through the low-speed system. The low-
speed system is illustrated in Fig.
E-9.
Liquid
fuel enters the idle well through the metering rod jet.
Low-speed
jet measures the amount of fuel for
idle and early part-throttle operation. Air-by-pass,
economizer, and idle air bleed are carefully
cali
brated
orifices which serve to break up the liquid
fuel
and mix it with air as it
moves
through the passage to the idle port and idle adjustment screw
port.
E-14.
Idle Mixture Adjustment
Note:
The idle mixture adjustment procedure for
the late model
YF-4941S
and
YF-6115S
Carter
Carburetor
equipped with the
External
Idle
Mixture
Limiter
Cap is the same as outlined below 114

E
FUEL
SYSTEM
pressing downward on metering rod) or
seats
be
fore the metering rod arm makes flat contact with the pump lifter link, make adjustment by bending
the lip on the metering rod arm.
E-17.
Choke System
The
choke system consists of a manually-operated
choke valve, a fast-idle connecting rod, and a fast-
idle arm. The choke valve is offset-spring loaded to prevent over-choking during the starting warm-
up period. When the choke valve is moved to a closed position for starting, the fast idle connector
rod
in Fig. E-ll revolves the fast idle link.
This
action increases the
engine
idle speed to prevent stalling during the warm-up period. A fast-idle
connector rod return spring prevents partial closing
of the choke valve. pump lifter which is connected to the throttle.
This
movement forces fuel from the chamber
above the diaphragm through discharge pump check valve and discharge pump jet.
This
auxiliary discharge of fuel supplies
engine
requirements for
quick
acceleration and heavy loads. When the
throttle is closed, the diaphragm is again pulled
down by high vacuum and another measured
charge of fuel enters the chamber above the
diaphragm
through the intake passage to be
available for the next cycle of operation.
Note:
The pump jet (see insert drawing in Fig.
E-12)
projecting into the air stream is permanently pressed into the carburetor body and should not
be removed. Also, carburetor design makes it im possible to adjust the pump stroke.
FIG.
E-ll—FAST
IDLE
ADJUSTMENT
1—Fast
Idle
Connector Rod
2—Fast
Idle
Link
E-18.
Fast
Idle Adjustment
With
the choke held in wide open position, lip (No. 1) (Fig.
E-ll)
on the fast-idle rod should con
tact the
boss
on the body casting. Adjust by bend
ing the fast-idle link at
offset
as shown by (No. 2).
E-19.
Accelerating Pump System
The
accelerating pump system shown in Fig. E-12
provides a measured amount of fuel for rapid acceleration and smooth
engine
operation when
the throttle is opened at lower speeds. In operation,
vacuum
is applied to the underside of diaphragm
at all times when the
engine
is running.
Lower
and
more uniform vacuum is provided by vacuum
restriction
and vacuum bleed passage. When the
diaphragm
is in its maximum down position at
low throttle resulting from high vacuum in chamber the chamber above the diaphragm is full of fuel
which
has been admitted through intake passage.
When
the throttle is opened, vacuum drops in the
chamber and the diaphragm is initially forced
upward
by the spring on the diaphragm shaft.
The
upward motion is picked up by accelerator
|
13347
FIG.
E-12—ACCELERATING
PUMP
SYSTEM
1—
Pump
Fuel
Passage
6—Intake
Passage
2—
Discharge
Pump Jet 7—Diaphragm
3—
Pump
Check
Valve
Ball
8—Vacuum Chamber 4—
Bail
Check
Weight
9—Vacuum
Restriction
Jet
5—
Pump
Lifter
Arm 10—Vacuum Bleed Passage
E-20.
Accelerating Pump Maintenance
If
engine
acceleration is unsatisfactory, remove the
pump diaphragm and check the diaphragm for wear
or
damage. Then remove the pump check retainer
ring
located directly above the pump check weight
and
pump ball check. Pump ball check must seat
properly
as a leak
will
cause poor acceleration performance. Inspect and replace all worn or
damaged parts.
Clean
and blow out all passages
with
compressed air.
Note
that when testing the pump for discharge volume with the carburetor
off the engine, only half of the maximum pump capacity
will
be discharged. When the
engine
is
operating, vacuum controls the balance of dis charge. 116

E
FUEL
SYSTEM
Note:
Do not remove pressed-in parts such as
nozzle, pump jet, or antipercolator air bleed.
j.
Remove body flange attaching screws, body flange assembly, and gasket.
k.
Remove idle-adjustment screw, spring, idle
port
rivet, throttle lever assembly, washer, fast
idle arm, throttle plate screws, throttle plate, and throttle shaft.
1. Remove throttle shaft seal by prying out seal
retainer.
Note:
Do not remove pressed-in vacuum passage
orifice.
m.
Remove choke valve screws and choke valve.
Unhook
choke spring and slide shaft from housing,
n.
Wash all parts in carburetor cleaning solution
and
blow out passages with compressed air. Do not immerse diaphragm or seals in cleaning solution.
Inspect
all parts for wear or damage. Always use
new gaskets when reassembling.
E-22.
Carburetor
Reassembly
•
Refer to Fig. E-13.
To
expedite
reassembly, it is advisable to group all
related
parts by the circuit to which they belong.
a.
Install
throttle shaft seal and retainer in flange casting.
b.
Install
fast-idle
arm,
washer, and lever assembly
on throttle shaft. Slide shaft into place and install throttle valve.
c.
Install
idle port rivet plug and idle adjusting
screw
and spring.
d.
Attach flange assembly to body casting. Use new gasket.
e.
Install
low-speed jet assembly.
f.
Early
production models install pump intake
strainer
in pump diaphragm housing and carefully
press into recess.
Note:
If strainer is even slightly damaged, a new
one must be installed.
g.
Install
pump diaphragm assembly in diaphragm housing.
Then,
install pump diaphragm spring
(lower)
and retainer.
h.
Install
pump lifter
link,
metering rod
arm,
upper
pump spring, and retainer.
I.
Install
metering rod jet.
Note:
No gasket is used with this jet.
j.
Install
diaphragm housing attaching screws in
the diaphragm housing, making sure that the
edges
of the diaphragm are not wrinkled.
Lower
into place and tighten screws evenly and securely,
k.
Install
throttle shaft seal, dust seal washer, and
shaft seal spring.
I.
Install
pump connector
link
in the throttle arm
assembly.
Install
throttle shaft arm assembly on
throttle shaft guiding connector
link
in pump lifter
link
hole.
CAUTION:
Linkage
must not bind in any throttle
position. If binding occurs,
loosen
clamp screw in
throttle arm, adjust slightly, then retighten screw.
m.
Install
pump check disc, disc retainer, and lock
ring.
n.
Install
metering rod and pin spring. Connect
metering rod spring.
o.
Check
and if necessary correct meter ing rod adjustment. Follow procedure of
Par.
E-16.
p.
Install
needle
seat and gasket assembly, needle,
float
and
float pin. The
stop
shoulder on the float
pin
must be on the side away from the bore of
the carburetor.
q.
Set float level to specifications. Follow pro cedure of
Par.
E-12.
r.
Install
air horn gasket and air horn assembly.
Install
attaching screws, lock washers, and choke
tube clamp assembly. Tighten center screws first,
s. Slide choke shaft and lever assembly into place
and
connect choke lever
spring.
Install
choke valve.
Center
the valve by tapping lightly, then hold in
place with fingers when tightening screws,
t.
Install
fast-idle connector rod with
offset
portion
of rod on top and pin spring on outside.
Install
fast-idle connecting rod spring.
E-23.
Correcting Acceleration
Flat
Spot
Early
production
Carburetor
Models 938-S, 938-
SA,
938-SC
Inasmuch
as a flat
spot
on acceleration or low speed
stumble can
come
from causes other than
car
buretor
malfunction, it is recommended that
engine
tuning be thoroughly checked before attempting
any
actual carburetor work. Make sure that
ignition, compression, and timing are correct and
that fuel pump is supplying enough gas. Also, the F-head
engine
employs a water-heated intake
manifold.
Proper vaporization of the fuel depends
on correct intake manifold temperature. Since this
temperature is controlled by the cooling system
thermostat, include an operational check of the
thermostat when diagnosing the stumble. Operating
temperatures consistently below
155°F.
can cause stumble.
If
the stumble persists, a
YF-938-S,
YF-938-SA,
or
YF-938-SC
carburetor can be converted to a
YF-938-SD
carburetor by installing Special Kit
924161, consisting of a pump discharge check
needle, a metering rod, and a metering rod jet. If this kit is installed, the pump discharge check
needle
replaces the original
ball,
weight, and re
tainer
and the small wire-type retainer used with
the
ball
check assembly must not be reinstalled.
When
installing the kit, check the size of the pump discharge jet, No. 2, Fig. E-14.
Early
production
YF-938S
and
YF-938SA
carburetors have a .025" [0,635 mm.] jet installed. If the carburetor being
converted has a .025" jet it must be opened up to .031" [0,787 mm.] by running a No. 68
drill
through
the jet as shown in
Fig.
E-14.
The jet must be drilled
as it is a pressed in part and cannot be replaced.
Upon
completing the installation of the conversion
kit,
mark
or tag the carburetor to indicate that it
is a
YF-938SD.
118

F
EXHAUST SYSTEM
FIG.
F-4—EXHAUST MANIFOLD-HURRICANE
F4
ENGINE
1—
Stud
Nut
2—
End
Gasket
3—
Stud
4—
Manifold
5—
Center
Gasket
6—
Stud
7—
Gasket
F-5.
EXHAUST SYSTEM SERVICING
The
following paragraphs (F-6 through F-10)
describe the service that may be performed on the
exhaust system on the 'Jeep' vehicles.
F-6.
Exhaust Manifold Installation
When
assembling the exhaust manifold to the cylin der block on the F4 engine, install a new gasket. Before installing the manifold, have the mating
sur
faces clean and smooth. If stud threads on the
Hur
ricane
F4
engine
are damaged, correct the condition
with
a thread die or replace the studs.
When
installing the exhaust manifold, there should
be no bind
between
the manifold studs and stud
holes. Where such a condition is experienced, the stud
hole
at either end of the manifold must be
enlarged only enough to relieve the binding con
dition.
Torque
exhaust manifold attaching nuts 29 to 35 lb-ft. [4,0 a 4,8 kg-m.] on F4-134 engine, 15 to 20
lb-ft. [2,1 a 2,8 kg-m.] on V-6
engine
(as described
in
Par. C-5).
F-7.
Heat
Control Valve Replacement
Refer
to Par. F-3.
FIG.
F-5—EXHAUST MANIFOLD
-
LEFT
SIDE
V6
ENGINE
1—
Manifold
2—
Manifold
Heat Collector
J666S
14287
FIG.
F-6—HEAT CONTROL
VALVE
DAUNTLESS
V6
ENGINE
1— Weight
Forward
— Valve Open
2— Weight
Vertical
— Valve Closed 140

H
ELECTRICAL
SYSTEM
14365
FIG.
H-5—WIRING
DIAGRAM—F4
ENGINE
CURRENT
MODEL
1—
Left
Headlamp
2—
Left
Parking and Signal Lamp
3—
Right
Parking and Signal Lamp
4—
Right
Headlamp
5—
Marker
Lamp
— Amber
6—
Generator
7—
Distributor
8—
Ignition
Coil
9— Starting Motor
10— Battery Ground Cable
11—
12
Volt
Battery
12—
Flasher
(Directional Signal)
13— Instrument Cluster
A—Hi-Beam
Indicator
B—Auxiliary
C—Instrument Lights
D—Oil
Pressure
Indicator
E—Charging Indicator
F—Temperature Indicator
G—Fuel
Gauge
Indicator
H—Instrument Voltage Regulator
14—
Ignition
and
Starter
Switch
15—
Horn
Button 16—
Directional
Signal Switch 17— 4-Way
Flasher
Switch
18—
Flasher
(4-Way)
19—
Windshield
Wiper Motor Switch
20—
Main
Light
Switch
21—
Fuel
Gauge
Tank
Unit
22—
Back-Up
Light
Switch
23—
Marker
Lamp — Red 24—
Right
Tail
and Stop Lamp
25—
Right
Back-Up Lamp
26—
Left
Back-Up Lamp
27—
Right
Tail
and Stop Lamp
28—
Marker
Lamp — Red 29— Stop
Light
Switch
30— Foot Dimmer Switch
31—
Windshield
Wiper Motor Assembly
32—
Voltage Regulator
33— Temperature Sending
Unit
34—
Oil
Pressure
Sending
Unit
35— Spark
Plugs
&
Cables
36—
Horn
37— Junction Block
38—
Marker
Lamp — Amber
through a
two-position
push-pull switch located on
the
left
side
of the control panel.
The
foot-operated
headlight dimmer switch is
mounted on the floorboard to the
left
of the steering
column.
H-9.
PRESTOLITE
DISTRIBUTOR
—
DAUNTLESS
V-6 and
HURRICANE
F4
ENGINE
The
Prestolite distributor on the F4
engine
is
mounted on the right
side
of the
engine
and is op
erated by a coupling on the oil pump shaft, see Fig.
D-l,
which is driven by a spiral gear on the cam
shaft. The spark advance is fully automatic, being controlled by built-in centrifugal
weights.
The Pres
tolite
distributor on the V-6
engine
(Fig. H-8) is mounted at the
left
front of the
engine
on the tim
ing chain cover. It is driven by a spiral gear on the
camshaft. The spark advance is fully automatic,
being controlled by built-in centrifugal
weights,
and by a vacuum advance system. While
some
parts of the distributor may be checked or replaced
with the unit mounted on the
engine,
it is
best
to periodically remove it for a thorough check. Infor mation covering the parts which can be serviced
without removal is
given
below.
The
Prestolite distributor installed on the V-6 en
gine
is similar in construction to the distributor in
stalled on the F4
engines
except
for the addition of
a
vacuum advance mechanism.
The
same checking procedures outlined in Par. C- 10a, are used for the Prestolite V-6 distributor with
exception
of specifications.
H-10. Distributor Cap
The
distributor cap should be inspected for cracks,
carbon runners and
evidence
of arcing. If any of
these
conditions
exists, the cap should be replaced.
Clean
any corroded high
tension
terminals.
H-11.
Rotor
Inspect the rotor for cracks or
evidence
of
excessive
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 condition is found the distributor cap
segment
will 178

'Jeep'
UNIVERSAL
SERIES SERVICE
MANUAL
H
12955
FIG.
H-8—PRESTOLITE
DISTRIBUTOR—DAUNTLESS V-6 ENGINE 1—
Cap
2—
Rotor
3—
Lubricating
Wick
4—
Snap
Ring
5—
Condenser
6—
Contact
Set 7—
Breaker
Plate
8—
Cam
and Stop Plate 9—
Spring
(2)
10—
Governor
Weight
11— Cam
Spacer
12—
Gear
13—
Gear
Pin
14—
Washer
15—
O-Ring
Seal
16—
Bushing
17—
Distributor
Housing 18—
Vacuum
Chamber
19—
Washer
(Nylon)
20—
—Cap
Clamp
and Rings
21—
—Primary
Lead
22—
Washer
(outer upper,
23—
Washer
(inner upper)
2".—Drive
Shaft
H-14. Governor Mechanism
The
centrifugal advance mechanism consists of
an
automatic cam actuated by two spring con
trolled centrifugal weights. As the
speed
of the distributor shaft increases with
engine
speed, the
weights
are thrown outward against the pull of the springs.
This
advances the cam causing the contact
points
to
open
earlier and thus advancing the
spark.
The centrifugal
type
governor should be checked for free operation. Hold the governor shaft
and
turn the cam to the
left
as far as possible
and
release it. The cam should immediately return to the original position without drag. Should a distributor
test
fixture be available it is
best
to make a check through the entire advance
range, following the instructions of the fixture manufacturer.
The
vacuum control unit is mounted separately
on the
outside
of the distributor housing on the
V6
Prestolite distributor.
The
vacuum control unit consists of an enclosed
spring-loaded diaphragm linked mechanically to the distributor. The air-tight side of the diaphragm
is connected to the intake manifold side of the
carburetor.
Under part throttle operation, the intake manifold vacuum is sufficient to actuate the
diaphragm and cause the distributor to rotate in
its mount, thus advancing the spark and increasing fuel
economy.
During acceleration or when the
engine
is pulling heavily, the vacuum is not suf
ficient to actuate the diaphragm and the distributor
is held in the retarded position by a calibrated
return
spring which bears against the vacuum
diaphragm.
H-15.
Distributor Removal
a.
Remove high-tension wires from the distributor cap terminal towers, noting the order in which
they
are
assembled to ensure correct reassembly.
b. Remove the primary lead from the terminal
post
at the coil.
c. Unlatch the two distributor cap springs and re
move
the cap.
d.
Note
the position of the rotor in relation to the
base.
This
should be remembered to facilitate re installing and timing.
e. Remove the screw holding the distributor to the
crankcase
and lift the assembly from the
engine.
H-16.
Prestolite Distributor Disassembly
Refer
to Fig. H-8 and H-9.
a.
Remove the rotor. b. Remove the condenser.
c. Remove the distributor points.
d.
Remove nylon washer attaching vacuum advance arm to breaker plate, V6 only. Remove two 181