gas type JEEP CJ 1953 User Guide

Dl

DAUNTLESS
V-6
ENGINE
DM.
GENERAL

This
section describes service and repair of the
Dauntless V-6 engine. The
engine
code
number shown in
Fig.
A-4 is provided to identify the Daunt­

less
V6-225 engine. The meaning of the coded letters and numbers that are stamped on the right front face of the crankcase, just below the rocker
arm
cover,
between
exhaust manifold ports, is given
below.
Letter
to
Designate
Market

M
—
Military
E
—
Export

D
— Domestic
Letter
to
Designate
Year
Built

N
— 1967
P
— 1968

R
— 1969
S
— 1970

T
— 1971

Letter
to Designate
Engine
and Compression
Ratio

H—V6-225
9.0 to 1
C.R.
(2 Bbl.
Carb.)
Y—V6-225
9.0 to 1
C.R.
Marine
(Low
Profile)
(2
Bbl.Carb.)
Z—V6-225
9.0 to 1
C.R.
Marine
(High
Profile)
(2 Bbl.
Carb.)

K—V6-225
7.6 to 1
C.R.
(2 Bbl.
Carb.)
L—V6-225
7.4 to 1
C.R.
(2 Bbl.
Carb.)

Market

Domestic
—

Year
"1967"
Engine
J

Day

Plus Chg. If
Any-
Service Engine "S"
Short
Block
"R" -Oversize Bores "B"
Undersize Crank

&
"A"

Rod
Bearings

The
identifying letter or letters follow the
engine
letters are decoded as follows:
A—.010"
Undersize
Main
and Connecting Rod
Bearings

B—.010"
Oversize Pistons

AB—Combination
of A and B
S—Service
Engine

R—Short
Block

All
disassembly and assembly procedures are pre­ sented 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 sec­ tion F2.

Dl-2.
ENGINE
DESCRIPTION

The
Dauntless V-6
engine
has a displacement of
225 cubic inches. It has a compression ratio of
9.0 to 1, which permits use of regular-grade
gaso­

line.
See
Figs.
Dl-1 and Dl-2.

The
cylinder block is made of cast
iron.
Two banks
of cylinders (three cylinders per bank) are cast at a
90-degree
angle. The lower part of the cylinder-

block
extends
below the centerline of the
crank­
shaft, forming a continuous flat surface with the

rear
crankshaft main bearing cap and the timing

chain
cover.
This
design allows installation of an
oil
pan with a
one-piece
gasket. The cylinders in
the left bank (as viewed from the driver's seat) are
numbered
1-3-5,
from front to
rear.
The cylinders

in
the right bank are numbered
2-4-6,
from front
to
rear.

The
crankshaft is supported in the cylinder block
by four steel-backed full-precision bearings, all of

which
have an identical diameter.
Crankshaft
main bearings are numbered 1 to 4, front to
rear.
The

thrust
bearing is flanged to maintain crankshaft position and to compensate against crankshaft end

thrust
The No. 2 bearing is the thrust bearing.

The
crankshaft is counterbalanced by weights,
which
are cast integral with the
crank
cheeks. The

weights
are shaped to a contour which
gives
mini­
mum
clearance with cylinder barrels and piston

skirts
to conserve space.

Connecting
rods have I-beam sections with
bosses

on each side. Metal is removed, as required, to secure correct weight and balance. The lower end
of each connecting rod has a steel-backed preci­
sion bearing. The piston pin is a press fit into the upper end. The outer ends of the piston pin

are
a slide fit in the piston
bosses.

The
full-skirted, aluminum alloy pistons are cam ground and tin plated. Two compression rings and
one oil control ring are installed above the piston
pin.
The cast iron compression rings in the two

upper
grooves
of the piston have a
groove
or bevel cut around the inner
edge
on one side. The
top compression ring is installed with this
groove
or
bevel up. The lower compression ring is installed

with
bevel down. The oil
ring,
in the lower groove,
consists of two thin steel
rails
separated by a

spacer.
It is backed by a hump-type spring-steel
expander.

V-6
engine
cylinder heads are made of cast
iron.

Their
valve
guides
are cast integrally. Right and left cylinder heads are identical and interchange­
able. In service, however, it is
good
practice to
install
the cylinder heads on the side from which
they were removed.

The
valves are in line in each head, at an angle
10°
above the centerline of the cylinder bores.

Each
valve has a spring strong enough to ensure
positive valve seating throughout the operating speed range of the engine. The valve rocker arm
mechanism is protected by a
sheet
metal cover.
This
cover is seated on a raised surface of the
cylinder
head. It is gasketed to prevent oil leaks.

The
rocker arms for each bank of cylinders are mounted on a tubular steel shaft, supported on
the cylinder head by brackets. The rocker arms
are
made of aluminum. They have inserts at the

push
rod socket and the valve stem contact face.

The
camshaft is located above the crankshaft be­
tween the two cylinder banks; it is supported in
four steel-backed babbitt-metal bearings. The cam­ shaft is driven at one-half crankshaft speed by
sprockets and a single outside-guide type chain.

Hydraulic
valve lifters and
one-piece
push rods operate overhead rocker arms and valves of both

banks
of cylinders from a single camshaft.
This

system requires no lash adjustment during assem­
bly
or in service.

In
addition to its normal function of a cam follower,
each hydraulic valve lifter also serves as an auto- 76

E

FUEL
SYSTEM

9
©

FIG.
E-4—FUEL
EVAPORATIVE
EMISSION
CONTROL
SYSTEM-
DAUNTLESS
V-6
ENGINE
A—Side
View
1—
Charcoal
Canister

2—
P.C.V.
Crankcase
Valve

3—
Purge
Line

4—
Fuel
Tank
5—
Fuel
Filler
Hose
B—Plan
View
6—
Non-Vented
Gas Cap 7—
Vapor
Separator or Expansion
Tank

g—Fuei
Gauge

9—Fuel
Line-to-Fuel
Pump

10—Fuei
Return
Line

during
normal temperature vehicle operation, thus
minimizing
driveability problems. An additional
feature of this valve is a built-in vacuum relief

which
allows inward air flow under negative fuel

tank
pressure conditions. The valve housing con­
tains the normal tank vent and purge connections.

E-5.
Fuel Tank

The
fuel tank is external expansion type.
Fuel

tank
venting is accomplished by several vapor
lines which lead to the vapor separator or expan­
sion tank. The vapor lines which lead from the
fuel tank are located at the front and
rear
so that
during
any inclination of the vehicle, at least one
line
will
be open to vent at all times.
E-6.
Vapor Separator
or
Expansion Tank

The
vapor separator is chambered so that the
rear
fuel tank vent lines lead into a separate chamber

with
a fuel shutofl valve.
This
prevents solid fuel
from
flowing from the fuel tank to the vapor can­
ister during uphill operation or parking of the
vehicle. A single vapor vent line leads from the fuel
vapor separator to the vapor collection canister
where fuel vapors are stored until they can be drawn into the
engine
and burned.

The
expansion tank allows expansion of the fuel as

required
during temperature changes and simul­ taneously
becomes
a liquid trap that only allows
vapors to pass.
E-7.
Sealed
Gas Cap

The
sealed gas cap is designed to allow no vapors to
discharge into the atmosphere under normal
operation of the system. If the system
becomes
plugged or a failure of the demand valve occurs 112

'Jeep*
UNIVERSAL
SERIES
SERVICE
MANUAL

E
there is a relief valve that
opens
to reduce high
(dangerous) pressures in the fuel tank. In con­

junction
with the pressure relief valve there is a
vacuum
relief valve to
stop
collapse of the fuel

tank
in case of a plugged system or failure of the demand valve. When replacing the gas cap, the
same type must be used as originally installed.

E-8.
System Inspection Test

The
fuel emission vent system should be checked

carefully
to ensure the absence of any leaks to the
atmosphere of either liquid or vapor which might
affect the accuracy, safety, or performance of the control system.

To
assure that the sealed system has been properly

installed,
the following
test
procedure has been
developed.
Disconnect the vent line from the fuel tank system
to the activated charcoal canister, induce l/i p.s.i.
air
pressure. If this pressure can be maintained for

a
few seconds the vent system is assured to be sealed. DO NOT add air pressure to the canister
because damage can occur to the demand valve if
care
is not taken.

E-9.
Servicing the System

Periodic
Maintenance — Replace carbon canister filter at
12,000
miles
[19,200
km.] or 12 month in­tervals (more
often
for operation in dusty areas).

This
is the only regular maintenance service

required.

Canister
Filter
Replacement — Disconnect
hoses

from
top of canister, remove canister from mount
-

t
FIG.
E-5—CARBURETOR—
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 Shaft Assembly
7—
Idle
Speed Adjusting Screw
8—
Fast
Idle Connector Rod ing bracket. Remove cover from
bottom
of canister
by pulling it down to
disengage
clips. Remove and
discard
polyurethane filter element
(squeeze
ele­

ment out from under retainer bar).
Install
new
filter by squeezing element under retainer bar and positioning it evenly around entire
bottom
of
canister with
edges
tucked under canister lip, snap

bottom
cover in place, reinstall canister on bracket

and
reconnect
hoses.

Vapor
line
hoses
used in this system are made of

special
rubber material.
Bulk
hoses
are available for
parts
service.
Ordinary
rubber
hose
should not be
used to service vapor lines as they are subject to deterioration and may clog the system.
Liquid

vapor separators or expansion tanks and canisters

are
serviced as complete units only.
Canister
air filters, however, are serviced separately.

E-10.
CARBURETOR
—
HURRICANE
F4
ENGINE

A
single-barrel manual choke, down-draft carbure­
tor (Fig. E-6) is used on the
Hurricane
F4 engine.
The
carburetor is internally vented by a tube
opening located in the air horn body of the
car­

buretor.
This
opening is connected by a rubber
tube to the air
outlet
horn of the air cleaner thus
allowing only filtered atmospheric pressure air
to enter the float chamber for balance pressure
of the carburetor fuel.

Note:
A carburetor with a specific flow character­

istic
is used for exhaust emission control. The
carburetor
is identified by a number, and the correct

carburetor
must be used, when replacement is
necessary.

Early
production models
CJ-3B,
CJ-5,
CJ-5A,
CJ-6,
and
CJ-6A
have a
Carter
YF-938SD
carbure­
tor superseding the earlier
YF-938SC,
YF-938SA,

or
YF-938S
models.

Note."
Conversion kits for changing earlier models
to SD models are available. See Par E-23. It is recommended that when a carburetor is converted
that a tag be fashioned stamped with the new model number and installed under one of the air

horn
screws.
Look
for such a tag to determine if
the carburetor has previously been converted.

Carburetors
listed above are all in the same YF
series and have only minor differences. Descriptions
and
repair procedures given in the following
para­
graphs apply equally to all
YF-series
carburetors.
YF-series
carburetors employ manual and vacuum
control of the metering rod and accelerator pump.
The
carburetor controls and vaporizes the fuel
through five separate systems: float system, low-
speed system, high-speed system, choke system,

and
accelerating-pump system. A description of the function and operation of each system provides an over all description of the carburetor.

For
identification, the series designation is stamped
on the body under the name
Carter
and the model
designation is stamped on a flange protruding
from
the body.

Note:
When checking for carburetor icing causes,
also check the vacuum-pump-to-manifold vacuum
line connector. 113

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

'Jeep'
UNIVERSAL SERIES SERVICE
MANUAL

E
possibility of vapor lock by keeping cool fuel from
the tank constantly circulating through the fuel
pump.

Fuel
pump pressure at carburetor (inlet) on Daunt­
less
V6-225
engine
should be 3% lbs.
[0,264
kgm-cm2] minimum at idle with the vapor return
hose

squeezed off. With the vapor return
hose
open
pump pressure should be 2j^ lbs. [0,176 kg-cm2]
minimum.

The
Dauntless V-6
engine
is equipped with a sealed

unit,
non-repairable, single-action fuel pump (Fig.

E-33).

Note:
All Dauntless V-6
engines
are equipped with

a
throw-away can-type gasoline filter installed in
the fuel line
between
the fuel pump and the
car­
buretor.
This
unit must be replaced every
12,000
miles
[19.200
km.] of vehicle operation.

E-68.
Fuel
Pump Removal

To
remove the fuel pump from the Dauntless V-6
engine, disconnect the fuel inlet, fuel
outlet
and fuel return lines from the pump. Remove the two
fuel pump body attaching cap screws and lock

washers.
Pull
the fuel filter bracket free and remove the pump and gasket. Discard pump and gasket.
Install
new pump in reverse procedure of removal.

E-69.
AIR
CLEANER

Servicing
of the air cleaner is properly taken care of as part of the periodic lubrication and servicing of the vehicle. For this reason, air cleaner servicing
information is given in the Lubrication Section.

Refer
to and follow the instructions given there.

E-70. ACCELERATOR LINKAGE
The
accelerator linkage is properly adjusted when
the vehicle leaves the factory. However, in time
components parts
will
become
worn and require re­
adjustment to maintain a smooth even control of
engine
speed. On Models equipped with F4
engines

the adjustment is made at the adjusting block,

Fig.
E-34. Loosen the lock nuts, and adjust the length of the accelerator rod so that when the
car­

buretor throttle valve is wide open the accelerator
treadle
will
just strike the toe board. After correct
adjustment is made tighten both lock nuts firmly.
To
adjust the accelerator linkage on V6
engines

loosen
the lock nuts securing the accelerator rod
housing to its securing bracket and adjust the length
of the accelerator rod so that when the carburetor throttle valve is wide open the accelerator treadle

will
just strike the toe board. After correct adjust­
ment is made, tighten lock nut firmly, see Fig. E-35 for Dauntless V-6 engine.

E-71. FUEL
TANK
AND
FUEL LINES
The
following paragraphs (E-70 through E-73) describe the removal, installation and services to
be performed when replacing the fuel tank or
servicing
the fuel system.

FIG.
E-34—ACCELERATOR LINKAGE,
F4
ENGINE
1—
Grommet

2— Nut and Lockwasher

3—
Throttle
Control
4—
Choke
Control 5—
Treadle
Rod Seal
6—
Accelerator
Treadle
7—
Treadle
Hinge Pin
8—
Treadle
Hinge 9— Nut and Lockwasher
10—
Screw

11—
Accelerator
Rod
12— Nut
13—
Adjusting
Block
14—
Retracting
Spring
15—
Cotter
Pin
16—
Lower
Beilcrank
17—
Washer

18—
Beilcrank
Link
Rod
19—
Bracket

20—
Throttle
Wire
Stop
21—
Beilcrank
Spring
22—
Rod

23—
Upper
Beilcrank
24—
Wesher
10731
131

'Jeep'
UNIVERSAL
SERIES
SERVICE
MANUAL

E
portant that
these
lines are not accidentally re­
versed.

When
installing the fuel tank on late model vehicles, position the tank
between
the frame
rail

to allow space to connect the fuel line(s), vent
hose

and
sending unit wire. After connecting
these
items, align and secure tank to frame brackets.
Position filler
hose
on tank filler neck and tighten
hose
clamp.
Fill
tank with fuel and check for leaks.

When
installing the fuel tank on early model vehicles, reverse the order of removal as given in

Par.
E-73.

E-75.
Fuel
Tank
Cap

A
surge pressure type fuel tank filler cap is used on

all
models.
This
is necessary to prevent fuel leakage
from
the cap vent opening when the vehicle is on a
side slope. Two spring loaded relief valves which
open when venting is required are built into the
cap.
Should the pressure valve
fail
to open, pressure
in
the tank may force fuel by the carburetor inlet
valve causing flooding.
Failure
of the vacuum valve may prevent flow of fuel to the carburetor. Should
the valves
fail
to vent install a new cap.

Note:
Vehicles having a
Fuel
Evaporative
Emis­

sion System are equipped with a non-vent sealed gas cap. The sealed cap is designed to allow no
vapors to discharge to the atmosphere. No other type of cap is to be used on vehicles having this
type system.

E-76.
Fuel
Gauge Float Unit

The
fuel tank
gauge
float unit is mounted in the top
of the fuel tank and consists of a housing enclosing
a
rheostat that is actuated by the float arm, and a
float
which
moves
with the fuel level in the tank.
On
V-6 and current production F4
engine
equipped vehicles, the fuel
outlet
pipe is integral with the
float
unit.
The fuel
outlet
pipe has a mesh filter on the inner end.

Note:
Under no circumstances should a fuel tank

gauge
be installed without a mesh filter element.

The
filter,
outlet
pipe, and float unit are locked as

an
assembly to the top of the fuel tank. To remove,

turn
the lock plate that secures the float unit
assembly.

E-77.
Fuel
Lines

Check
lines and connections occasionally for leaks,
and
for severe kinks that might restrict the flow of
fuel. If an excessive amount of
dirt
is found in the
carburetor
or fuel pump, the fuel tank should be
drained
and the fuel lines blown out with com­
pressed air.

All
rubber fuel lines and their respective clamps should be checked occasionally to be certain they
are
correctly positioned and not leaking. 133

'Jeep'
UNIVERSAL
SERIES
SERVICE
MANUAL

F F-8.
Exhaust
Pipe Replacement

When
replacing the exhaust pipe(s) refer to
Figs.
Fl,
F2 and
F-3.
Remove the nuts securing the ex­
haust pipe(s) to the exhaust manifold(s), loosen

and
disconnect mounting
clamp
(s)
as necessary, loosen clamp securing exhaust pipe to muffler and
remove exhaust pipe(s).
Note: Always use new gasket(s) between exhaust
pipe(s) and exhaust manifold(s). After installation
of exhaust pipe(s), check the exhaust system for
alignment and leaks.

F-9.
Muffler Removal and Replacement
Disconnect the support bracket and clamps on each
side of the muffler. Loosen the
tail
pipe support
clamp
bolt and
pull
the
tail
pipe to the
rear
until

it
is free of the muffler. Remove the muffler. To

install
the muffler, reverse the above
steps
and

properly
align the complete system, then tighten
connecting support brackets securely. Operate the engine and check for possible leaks.
F-10.
Tail
Pipe Removal and Replacement
Refer
to
Figs.
F-l,
F-2 and
F-3.

Disconnect the support bracket and clamps both at the
rear
of the muffler and also at outlet end of
the
tail
pipe.
Free
the
tail
pipe from the muffler. To
assemble, position
tail
pipe to the muffler and secure clamps, being careful to align the exhaust
system so it doesn't contact body or frame.
Check

system for exhaust gas leaks.

F-ll.
EXHAUST SYSTEM SPECIFICATIONS
EARLY
MODEL
HURRICANE
F4
ENGINE
EARLY
MODEL
DAUNTLESS
V-6
ENGINE

TYPE:

Muffler:
Type

Exhaust
Pipe:

Wall
Thickness

Tail
Pipe:

Crossover
Pipe
Diameter
Single

Reverse
Flow

1.625*
[4,13 cm.] .065* [1,6 ram.]

1.625*
[4,13 cm.] Single
With
Cross-Over

Reverse
Flow
2.00* [5,08 cm.] .065* [1,6 mm.]
2.00* [5,08 cm.]
2.00* [5,08 cm.] .065* [1,6 mm.]

Wall
Thickness Single
With
Cross-Over

Reverse
Flow
2.00* [5,08 cm.] .065* [1,6 mm.]
2.00* [5,08 cm.]
2.00* [5,08 cm.] .065* [1,6 mm.]

LATE
MODEL
HURRICANE
F4
ENGINE
LATE
MODEL
DAUNTLESS
V6
ENGINE

TYPE:
Muffler:

Exhaust
Pipe:
Wall
Thickness

Exhaust
Pipe Extension:

Wall
Thickness

Crossover
Pipe: Single

Reverse
Flow
2.005* [5,09 cm.]

1.755*
[4,46 cm.]

1.625*
[4,13 cm.]
.065* [1,6 mm.]

1.629*
[4,14 cm.] 2.00* [5,08 cm.] .065* [1,6 mm.] Single with
Cross-Over

Reverse
Flow
2.005* [5,09 cm.]

1.755*
[4,46 cm.]
2.00* [5,08 cm.] .065* [1,6 mm.]
2.00* [5,08 cm.] .065* [1,6 mm.]

1.753*
[4,45 cm 1

Wall
Thickness

Tail
Pipe
1.753*
[4,45 cm.] Single with
Cross-Over

Reverse
Flow
2.005* [5,09 cm.]

1.755*
[4,46 cm.]
2.00* [5,08 cm.] .065* [1,6 mm.]
2.00* [5,08 cm.] .065* [1,6 mm.]

1.753*
[4,45 cm 1 141

'Jeep'
UNIVERSAL SERIES SERVICE
MANUAL

Fl
EXHHUST
EMISSION
CONTROL
SYSTEM

Contents

HURRICANE
F4-134
ENGINE
SUBJECT
PAR.

GENERAL
Fl-1

AIR
PUMP
Fl-2

PUMP
AIR
FILTER
Fl-3

AIR
DELIVERY
MANIFOLD
Fl-4

AIR INJECTION TUBES.
Fl-5

ANTI-BACKFIRE
DIVERTER
VALVE.
.Fl-6

ENGINE
COMPONENTS
. .Fl-7
Carburetor
. .Fl-8

Distributor
........
.Fl-9
Exhaust
Manifold Fl-10

MAINTENANCE
Fl-11
Carburetor
Fl-12,
Fl-13

Distributor
Fl-14

Anti-Backfire
Diverter
Valve.
.........
.Fl-15

Check
Valve Fl-16

Fl-1. GENERAL—F4-134
Engine

The
Hurricane
F4-134
engine
Exhaust
Emission
Control
System consists of a belt driven air pump

which
directs compressed air through connecting

hoses
to a steel distribution manifold into stainless steel injection
tubes
in the exhaust port adjacent
to each exhaust valve stem.
This
air with its normal

oxygen
content, reacts with the hot but incom­
pletely burned exhaust
gases
and permits further combustion in the exhaust port or manifold.
Fl-2. AIR
PUMP

The
air injection pump is a positive displacement
vane type which is permanently lubricated and
requires
no periodic maintenance.

The
pump contains an integral relief valve which controls the air supplied to the
engine
exhaust ports

during
high speed operation to limit maximum ex­
haust system temperatures.

Fl-3. PUMP
AIR
FILTER

The
air filter attached to the pump is a replaceable
element type constructed of conventional pleated
paper
with steel end plates.

The
filter should be replaced every
12,000
miles
[19,200
km.] under normal conditions or sooner

under
adverse weather or driving conditions.

Fl-4.
AIR
DELIVERY
MANIFOLD

The
air delivery manifold, constructed of cold
rolled
steel with a zinc plating, distributes the air

from
the pump to each of the air delivery
tubes

in
a uniform manner.

A
check valve is attached to the air delivery
SUBJECT
PAR.

Air
Pump Fl-17
Carburetor
Air Cleaner Fl-18

REMOVAL PROCEDURES
.Fl-19
Air
Pump
Fl-20
Anti-Backfire
Diverter Valve Fl-21
Air
Distribution Manifold,
And
Air Injection Tubes
Fl-22

REQUIRED
EQUIPMENT
.Fl-23

REPLACEMENT
PARTS
Fl-24

WARRANTY
Fl-25

DIAGNOSIS
GUIDE
Fl-26
MAINTENANCE CHART
Fl-27

CARBURETOR SPECIFICATIONS
Fl-28

DISTRIBUTOR SPECIFICATIONS
Fl-29
SPARK PLUG
GAP
.Fl-30

manifold.
Its function is to prevent the reverse flow
of exhaust
gases
to the pump should the pump
drive
fail.
This
reverse flow would damage the air
pump and connecting
hose.

Fl-5.
AIR
INJECTION
TUBES

The
air injection
tubes
of stainless steel are inserted
into machined
bosses
of the exhaust manifold. The

tubes
project into the exhaust ports directing air
into the vicinity of the exhaust valve stem.

Fl-6.
ANTI-BACKFIRE DIVERTER VALVE

The
anti-backfire diverter valve prevents
engine
backfire
by briefly interrupting the air being in­
jected into the exhaust manifold during periods of deceleration (rapid throttle closure).

Fl-7.
ENGINE
COMPONENTS

The
following items
vary
in design or specifications

from
those
on vehicles not equipped with the Ex­
haust Emission
Control
System.

Fl-8.
Carburetor

A
carburetor with a specific flow characteristic is used for exhaust emission control.

A
carburetor dashpot is provided to control the throttle closing speed.

Fl-t.
Distributor

The
ignition distributor used with the exhaust emission system requires a different advance curve

from
that used on the F4-134
engine
prior
to the
introduction of exhaust emission systems. 143

'Jeep'
UNIVERSAL SERIES SERVICE
MANUAL

Fl
EXHAUST
EMISSION
CONTROL
SYSTEM

Contents

DAUNTLESS
V-6
ENGINE
SUBJECT
PAR.

GENERAL
.F2-1
HEATED
AIR
SYSTEM.
. F2-2
Testing
Thermo
Air
Cleaner
F2-4
Positive
Crankcase
Ventilation
Valve.
. . .F2-6

Vacuum
Motor Replacement . .F2-8
Air
Cleaner Sensor Replacement F2-9
Replacement Procedures F2-7

AIR
PUMP
.F2-10

AIR
FILTER.
F2-11

AIR
DELIVERY
MANIFOLD.
F2-12

AIR INJECTION TUBES.
F2-13

ANTI-BACKFIRE
VALVE..
.F2-14
ENGINE COMPONENTS
.F2-15
MAINTENANCE
.F2-3
Carburetor
F2-16, F2-17

Distributor
F2-18

Anti-Backfire
Valve . . F2-19
Check
Valve..
F2-20

F2-1.
GENERAL
—V-6
Engine

The
Dauntless V-6
engine
Exhaust
Emission
Con­

trol
System consists of a belt-driven air pump

which
directs compressed air through connecting
hoses
to a steel distribution manifold into stainless steel injection
tubes
in the exhaust port adjacent
to each exhaust valve.
This
air, with its normal
oxygen
content, reacts with the hot but incom­
pletely burned exhaust
gases
and permits further combustion in the exhaust port or manifold.

The
Exhaust
Emission System on V6-225
engines

limits
the hydrocarbon and carbonmonoxide emis­sions from the exhaust system. The system includes

an
engine
designed for low emissions and lean
carburetor
calibration at idle and part throttle.

The
lean carburetion is possible because of the
heated air system that is part of the Emission
System.
See Fig. F2-2.
With
the heated air system
operating, inlet air temperature is around
115°F.
[46°C],
after the first few minutes of operation.

This
makes the use of lean (hot weather)
cali­
bration
possible, and the vehicle
still
responds and

drives
well in cold weather.

The
engine
has a "ported"
spark
advance, with the

vacuum
take-off just above the throttle valve, so that there is no vacuum advance at closed throttle,
but there is vacuum advance as
soon
as the throttle is opened slightly. To reduce emissions at idle and
at lower
engine
speeds, the
engine
timing is such
that the distributor
will
not have centrifugal ad­
vance until about 900 RPM.
F2-2.
HEATED
AIR
SYSTEM

The
heated air system on late model V6 engines,
consists of a manifold heat collector, a heated-air
SUBJECT
PAR.

Air
Pump F2-21
Intake
Manifold F2-22
Carburetor
Air Cleaner F2-5, F2-23

REMOVAL PROCEDURES
F2-24
Air
Pump. F2-25
Anti-Backfire
Valve..
. . .F2-26
Air
Distribution Manifold,

And
Air Injection Tubes F2-27

REQUIRED
EQUIPMENT..
. F2-28
REPLACEMENT
PARTS..
.F2-29

WARRANTY
F2-30
DIAGNOSIS GUIDE
F2-31
MAINTENANCE CHART.
F2-32
GENERAL
SPECIFICATIONS
F2-33

CARBURETOR SPECIFICATIONS.
.... .F2-34

DISTRIBUTOR SPECIFICATIONS
. .F2-35
SPARK PLUG GAP
F2-36
pipe, a adapter elbow and an air cleaner contain­ing temperature control doors operated by vacuum
through a temperature sensor. The heat
stove
is a
sheet
metal cover, shaped to and bolted on with
the right exhaust manifold. Air drawn in along the lower
edge
of the
stove
passes across the mani­
fold surface, picking-up heat. The heated air is
drawn
out from the front of the manifold, through
the heated air pipe and adapter elbow into the
snorkel
of the air cleaner.

The
temperature control air cleaner is designed to mix this heated air with cold air from under the
hood so that carburetor inlet air temperature aver­
ages
about
115°F.
[46°C.].
This
mixing is
done
by two air doors, a cold air door and a hot air door,

which
move
together
so that when the cold air door is closed, the hot air door is open and vice
versa.
Most of the time, both doors
will
be partially
open as required to control the temperature. When
the underhood temperature reaches about 135
°F
[57°C]
the cold air door
will
open wide and the
hot air door
will
close
tight See Fig. F2-3. Ob­ viously, if underhood temperatures rise above
135°F.
[57°C]
the air cleaner
will
no longer be
able to control temperatures and the inlet air tem­

perature
will
rise with underhood temperature.
The
temperature doors are moved by a diaphragm
type vacuum door. When there is no vacuum pres­ ent in the motor, the diaphragm spring forces the
cold air door open and the hot air door closed.

Whenever
the
engine
is running, the amount of
vacuum
present in the vacuum motor depends on
the temperature sensor in the air cleaner which is located in the vacuum line
between
the intake
manifold and the vacuum motor. In the sensor, a 149

'Jeep'
UNIVERSAL
SERIES SERVICE
MANUAL

F2

FIG.
F2-4—HOT
AIR
DOOR
OPEN

1—
Linkage

2— Motor
3—
Air
Cleaner
4— Sensor 5—
Temp
Sensing Spring
6—
Air
Bleed Valve 7—
Hot
Air Pipe 8—
Diaphragm
Spring
9—
Diaphragm

10—
Control
Damper
11—
Air
Inlet
12—
Vacuum
Chamber
13—
Snorkel
Tube
To
perform the thermometer check, proceed as
follows:
1. Start
test
with air cleaner temperature below
85°
F.
[29.4°
C.]. If
engine
has been run recently, allow it to cool down. While
engine

is cooling, remove air cleaner cover and

install
a temperature
gage
next to sensor.

Reinstall
air cleaner cover. Do not install wing nut. Let car stand idle for
V2
hour or
more before proceeding to
step
2.
2. Start engine.
Cold
air door should
close
im­ mediately if
engine
is cool enough. When cold air door starts to open (in a few min­
utes), remove air cleaner cover and read
temperature
gage.
It must read 115° F.
[46°
C]
±20°.
3.
If cold air door
does
not start to open at
temperature indicated, temperature sensor is
defective and must be replaced.

F2-5.
Carburetor Air
Cleaner—Dry
Type

Every
24,000
miles
[38,400
km.] (or more fre­
quently in dusty territory) replace the air cleaner element. To do this, remove the wing nut and cover

from
the air cleaner housing.
Lift
out the air cleaner
element. Wipe the inside of the housing clean.
Service
the positive crankcase valve filler as out­
lined in paragraph F2-6. Make sure the air cleaner gasket is in
good
condition and properly located
on the carburetor flange.
Install
a new element, the cover and wing nut. Tighten the wing nut by hand.

Tighten
to make sure the air cleaner remains 153