1953 JEEP DJ oil

D

HURRICANE
F4
ENGINE

FIG.
D-7—PISTON
FITTING
b.
Check
and if necessary correct connecting rod
alignment using a connecting rod aligning fixture,

such
as the one shown in Fig. D-8, in accordance
with
the instructions furnished with the fixture.

c.
Check
the piston pin fit. The piston pins are fitted
with
a clearance of .0001" to .0003" [0,0025

a
0,0076
mm.] which approximates a light thumb
push
fit at room temperature. See Fig. D-9. The piston pins are anchored in the rods with lock

screws.
Installation of oversize pins in this
engine

is not recommended as experience has shown that
should a pin be worn sufficiently to require replace­ ment, the piston should also be replaced.

Clamp
the connecting rod in a vise using
jaw
shields
of
soft
metal or two pieces of hardwood, one on
each side of the rod and positioned approximately
3" [76 mm.] from the piston pin end.
Start
,
.. . | 10278 j

FIG.
D-8—CHECKING
CONNECTING
ROD
ALIGNMENT
1
—Feeler
Gauge
2—Fixture
FIG.
D-9—PISTON PIN
FITTING

the piston pin in the piston with the lock

screw
groove
facing down. Assemble piston to connecting rod with the piston
skirt
T-slot on
FIG.
D-10—CONNECTING ROD AND
PISTON

1—
Oil
Spray
Hole

2—
Piston
Skirt
T-slot

3—
Relative
Position
of
Camshaft

48

'Jeep'
UNIVERSAL SERIES
SERVICE
MANUAL

D

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

2—
Fixture

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

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

d.
Place piston and rod assembly in a connecting

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

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

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

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

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

ring
in squarely. End gap must be as shown in

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

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

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

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

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

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

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

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

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

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

D
HURRICANE
F4
ENGINE

10444

FIG.
D-14—PISTON
RING INSTALLATION D-37.
Piston Ring Application Chart

Cylinder
Bora
Ovtrsiie
Correct

Ring
Size
Ring
Gap

Fitting
End
Gap

Std.
te .009'

[•0,228
mm.]
Std.

None
.007' to
.045'
[0,1778 a
1.1430
mm.]

.010*
to .019'

[0,254
a
0,4826
mm.)
-.020'

File
fit .007'
to
.017'
[0,1778 a 0,4318 mm.]
.020'
to
.024'
[0,508 a
0,6096
mm.] -.020'

None
.007' to .029*
[0,1778 a
0,7366
mm.]
.025'
to
.029'
[0,635 a
0,7366
mm.] -.030'

File
fit

.007'
to .017*
.030' to .034*
[0,762 a
0,8636
mm.] -.030'

None
.007'to
.029'

.038'to
.039'

[0,8890
a
0,9908
mm.] -.040*

File
fit
.007'
to .017'
.040' [1,016 mm.]
-.040*
None
.007'
to .017'

D-38.
Crankshaft

The
crankshaft is machined from a heat-treated

carbon
steel forging and is carefully balanced both
dynamically
and statically. The crankshaft is
supported by three replaceable main bearings. The
front main bearing is flanged to take the end
thrust
of the crankshaft. A flanged section on the

rear
of the crankshaft acts as an oil slinger. While the crankshaft is out of the engine, handle it care­

fully
to prevent damage to the connecting rod
crankpins
and the main bearing journals. Refer
to
Fig.
D-l5.

D-39.
Crankshaft Inspection
and
Repair

Clean
out the drilled oil passages in the crankshaft

journals
with a small rifle brush making sure to get rid of all sludge or gum deposits. Blow out the passages with compressed air after cleaning.
Clean
the crankshaft thoroughly with a suitable
cleaning solvent. Inspect the crankshaft for
cracks,

alignment, and condition of the crankpins and the
main
bearing journals. Use magnafuix equipment,

if
available, to check for cracks or structural flaws.
Cracks,
misalignment, and scored or worn journals

and
crankpins necessitate crankshaft repair or replacement.

Check
crankshaft counterweights to be sure they
are
not
loose.

D-40.
Checking Crankshaft Alignment

To
check alignment, mount the crankshaft in the
cylinder
block with the front and
rear
bearings in
place but with the intermediate bearing removed.
With
a dial indicator mounted on the crankcase

and
the indicator button resting on the inter­mediate bearing
journal,
slowly rotate the
crank­

shaft and
note
the reading on the indicator
dial.
Install
the intermediate bearing and remove first
the front and then the
rear
bearings to repeat the operation with the dial indicator, checking the
front and
rear
bearing journals. The maximum allowable run-out is .002"
[0,0508
mm.].

D-41.
Checking Main Bearing Journals

An
ordinary 3" [7,62 cm.] micrometer may be used.
The
standard
journal
diameter is
2.334"
to 2.333" 50

-Jeep*
UNIVERSAL
SERIES SERVICE
MANUAL

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

D-42.
Checking Connecting Rod
Crankpins

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

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

cm.].
D-43.
Crankshaft
Main
Bearings

The
crankshaft rotates on three main bearings

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

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

and
the
rear
bearing caps. No dowel pins are used

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

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

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

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

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

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

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

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

will
require undersize bearings. Scored, flaked, or

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

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

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

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

D-45.
Fitting Crankshaft
Main
Bearings
Using
Plastigage

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

hole
in the bearing upper half registers properly

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

the crankshaft if replacing bearings with the
engine

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

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

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

regrind
the crankshaft.
Install
the bearing lower

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

shaft by hand to be sure it turns freely without

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

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

a.
Remove the bearing cap and carefully wipe

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

journal
(lengthwise of the crankshaft).

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

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

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

journal.

D-46.
Fitting Crankshaft
Main
Bearings
Using
Shim Stock

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

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

D

HURRICANE
F4
ENGINE

10442

FIG.
D-l6—SHIM
STOCK
IN
POSITION
ON
MAIN
BEARING

1—0.001"
Feeler Stock H' Wide feeler stock with light
engine
oil and lay it on the

bearing
in the cap, as shown in
Fig.
D-16.
With
the

shim
in this position, install the bearing and cap
on the crankshaft.

b.
Tighten the bearing cap nuts, first one and
then the other, a little at a time to 35 to 45 lb-ft. torque [4,8 a 6,2 kg-m.].

c.
Turn
the crankshaft by hand not more than
one inch in either direction.

Caution:
Turning
the crankshaft more may imbed the shim stock in the bearing, giving a false indica­
tion of fit and damaging the bearing.

If
the bearing clearance is correct, the piece of .001"
feeler stock should produce a light to heavy drag.
If
there is little or no drag the bearing fit is too

loose.
If the crankshaft
will
not
turn
there is not
enough clearance. In either case another bearing must be selected to provide the proper fit.

d.
After the bearing has been correctly fitted, remove the shim stock, wipe the bearing and

journal
carefully and apply clean
engine
oil to the
surfaces.
Replace the cap and tighten the nuts first one, then the other, a little at a time, to the
prescribed
torque. The crankshaft should now
turn

freely without drag.
FIG.
D-l
7—CONNECTING
ROD
OFFSET
D-47.
Connecting Rod Bearings

The
connecting rod bearings, like the crankshaft
main
bearings, are of the replaceable type. When

correctly
installed, the bearings provide proper
clearance
without filing, boring, scraping, or

shimming.

Main
bearings with maximum wearing surfaces
are
obtained through the use of
offset
connecting

rods.
When the rods are installed, the
offset
"A"

in
Fig. D-l7 is placed away from the nearest main

bearing
"B".
The
oil spray
hole
should be on the "follow" side

or
away from the camshaft, toward the right side
of the vehicle. Because of the
offset
and oil spray
hole, No. 1 and 2 or No. 3 and 4 connecting rods cannot be interchanged for if they are reversed,
the oil spray
hole
will
be on the wrong side. No. 1
and
3 or No. 2 and 4 can be interchanged.

Connecting
rod bearings should be replaced as a complete set.
Each
bearing consists of two halves.

Connecting
rod bearing
sets
are available in stand­

ard
size and the following undersize:
.001" [0,025 mm.] .012" [0,305 mm.]
.002"
[0,051
mm.] .020" [0,508 mm.] .010"
[0,254
mm.] .030" [0,762 mm.]

The
.001" and .002" undersize bearings are for use

with
standard size crankshafts having slightly

worn
crankpins that do not require grinding. The .012" undersize bearings are for use with slightly

worn
crankshafts that have been previously ground for .010" undersize bearings.

Should
it be necessary to replace the bearings due to wear, replacement of piston rings and piston
pins is also recommended.

NOTE:
Should it be necessary to replace a scored

or
burned No. 1 connecting rod bearing, see Par. D-92 regarding timing gear oil jet.

D-48.
Connecting Rod Bearing Inspection

The
bearing fits may be roughly checked by shaking the connecting rod by hand,
prior
to removal of
the bearing cap, to determine if it is
loose
on the
crankshaft.
The crankpins must be carefully in­
spected as detailed previously in Par. D-41.
Worn
crankpins
will
require undersize bearings. Scored,
flaked,
or
worn bearings must be replaced.

D-49.
Installing Connecting Rod Bearings
New bearings must be installed so that the oil

spray
hole
in the upper bearing
half
aligns with
the oil spray
hole
in the connecting rod.
Each

bearing
cap must be installed to seat evenly on the connecting rod from which it was removed, and in
the same position. After wiping and carefully in­ specting the bearing bore in the connecting rod,

install
the proper bearing. Never file either the
bearing
cap or the bearing to compensate for too
much
clearance. Do not use shims under a bearing
cap or behind a bearing shell. Do not run a new

bearing
half
with a worn half.

The
desired running fit (difference
between
the diameter of the
crankpin
and the inside diameter
of the fitted bearing) for a connecting rod bearing
is .0003" to .0025"
[0,0076
a
0,0635
mm.].
With
a dimension in
excess
of this standard running fit, a 52

'Jeep'
UNIVERSAL
SERIES
SERVICE
MANUAL

D
satisfactory bearing replacement cannot be made

and
it
will
be necessary to regrind the crankshaft.

Install
the bearing lower
half
and the connecting

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

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

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

larger
bearing is required. If there is no binding

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

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

checking
connecting rod bearing clearances.
This

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

D-50.
Connecting
Rod
Side Play

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

D-51.
Camshaft and Bearings

The
camshaft is supported at four points in the

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

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

cated through drilled passages in the crankcase.

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

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

The
fuel pump is actuated by an eccentric forged

onto
the camshaft.

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

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

and
must not be scored or worn.

D-52.
Camshaft
Front Bearing Replacement

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

bearing
in until the front end of the bearing is

flush
with the front surface of the cylinder block.

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

bearing.

D-53-
Camshaft End Play

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

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

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

When
this is correct and the parts are assembled

and
drawn tightly
together
by the gear retaining

screw,
the end play should
come
within standard
limits.

D-54.
Timing Gears
and
Cover

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

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

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

shaft pulley, crankshaft oil slinger, and the
crank­

shaft drive gear spacer. The timing gears are

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

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

D

HURRICANE
F4
ENGINE
against the hub of the crankshaft pulley.
Timing

gears are accessible for inspection or replacement

with
the
engine
installed in the vehicle after re­ moving the radiator, belt drive pulley, and timing
cover.

Should
it be necessary to replace the timing gears, attention must be given to the end float of both
the camshaft and crankshaft and to the running

clearance
of both gears. It is also advisable to
check
both the oil jet and oil passage to the
crank­

shaft front bearing to be sure that they are clear.

D-55.
Inspection and
Repair

Check
the general condition of both gears and
inspect for evidence of excessive wear. Replace
excessively worn or damaged gears. Inspect the
cover and replace if bent or damaged. It is recom­ mended that the crankshaft oil seal in the cover
be replaced when the cover is removed to ensure a
good
seal around the crankshaft. To replace this

seal
with the
engine
in the vehicle
requires
removing
the radiator and water pump.

D-56.
Valves, Springs, and Guides

The
exhaust valves seat on the top of the cylinder

block
with the
stems
extending down through
replaceable valve guides. The exhaust valves are actuated by the camshaft through exhaust valve
tappets. The exhaust valve springs are assembled

and
locked on the lower end of the exhaust valve
stems. The retaining locks are the split type, which
fit in a recess on the valve
stems
and into the taper

in
the valve spring retainers.

Adjustment
of exhaust valves is by means of the
adjusting
screw threaded into the upper end of the
exhaust valve tappets. An exhaust valve rotator used as a valve spring retainer is installed on the
lower end of the exhaust valve.
This
valve rotator,
known
as "Roto Cap", is a spring-loaded
ball

bearing
device. On each lift, or opening stroke of
a
valve, the rotator
gives
the valve a slight positive
clockwise rotation.

The
intake valves operate in valve
guides
in the
cylinder
head and are actuated by rocker arms.

The
rocker arms are actuated by valve push rods

and
the intake valve tappets. The intake valve
springs,
the intake valve spring retainers, and the

intake
valve spring retainer locks make up the

remainder
of the valve operating parts. An intake
valve spring retainer oil seal which encircles the

upper
end of the intake valve
between
the valve
locks and the upper end of the valve spring re

tainer,
controls the passage of oil along the valve
stem and guide.

Note:
When
engine
trouble indicates defective
valves as a possible source of trouble, also check

all
vacuum line connections for possible leaks.

D-57.
Inspection of Valves, Springs,
and
Guides

Clean
the valves on a wire wheel, making sure that

all
carbon is removed from the top and the under­
side of the heads and that all gum and varnish
deposits
are removed from the stems.
Polish
the valve
stems
with steel wool or crocus

cloth.
Visually
inspect all valves for warpage,

cracks,
or excessive burning and discard if one of

these
conditions exists. Replace any worn, pitted,

or
corroded valves that cannot be cleaned with a
wire
brush.
Replace any valves when
seats
are pitted, burned, or corroded so badly that they
cannot be cleaned up with a light refacing on a valve refacing machine.

Replace
valves with marks of scoring or abrasion visible on the stem. Replace any valves with bent

stems
which
will
be apparent when the valve is
mounted in the valve refacing machine.

Note:
Use only hard-face exhaust valves for
replacement.

Examine
the
stems
of valves which employ the
ball
bearing rotators.
Wear
marks around the
cir­

cumference of the
stems
indicates that the valve is
rotating satisfactorily.
Vertical
heavy pressure

areas
indicate that the valve is not rotating and the valve spring retainer (Roto
Cap)
should be replaced

if
at fault.
Check
the diameter of the valve stem at two or three places along the length of the stem

with
a micrometer. The intake valve stem diameter is .3733" to .3738" [9,482 a
9,495
mm.]. The
exhaust valve stem diameter is .371" to .372"
[9,423
a
9,449
mm.].

Note:
Exhaust
and intake valve springs are

similar
in appearance. They must not be inter­
changed as they have different spring
charac­

teristics.

Wash
the valve springs thoroughly in solvent.

Visually
examine the springs and replace any that

are
deformed or obviously damaged. Examine for

corrosion
from moisture or acid etching which might
FIG.
D-19—TESTING
VALVE
SPRING

1—
Torque
Wrench

2—
Spring
Testing
Fixture

3—
Valve
Spring
54

'Jeep'
UNIVERSAL
SERIES SERVICE
MANUAL

develop
into surface cracks and cause failure.

Measure
the over all free length of the springs and
replace any that do not measure to standard: 1%" [35,7 mm.] for intake valve springs and 2j^"
[63,5 mm.] for exhaust valve springs. If possible,
check each valve spring in a valve spring testing
fixture C-647 or equivalent as shown in Fig. D-l9.
Test
each spring when compressed to the two
different spring lengths given (representing valve closed and valve open spring length). If any spring
fails to register spring tension equal to or greater
than
the minimum load limit in pounds specified for that spring length, replace the spring.

Length
Minimun
Load

Intake
valve spring. . .
1.660"
[4,216 cm.] 66 lb. [29,9 kg.]
1.400"
[3,556 cm.] 140 lb. [63,5 kg.]

Exhaust
valve spring. 2.109" [5,356 cm.] 47 lb. [21,3 kg.]
1.750"
[4,445 cm.] 110 lb. [49,9 kg.]

Note:
When using a spring checking fixture C-647

or
equivalent as shown in Fig. D-l9, it is necessary
to convert the torque wrench reading which is in pounds-feet to the static pound pressure specified above according to the instructions furnished with
the wrench. For example, should the torque wrench reading be 50 lb-ft. and the wrench is two
feet
long
the static pressure of the spring
will
be 50 x 2 or 100 lbs.

Clean
the valve
guides
with a standard valve guide
cleaner or a wire
brush.
Check
the valve
guides
in the cylinder block. Replace valve
guides
which are

broken
or worn enough to cause excessive valve

stem-to-guide
clearance. See Par. D-61.
Standard
intake valve clearance is .0007" to .0022"

[0,0178
a
0,0559
mm.] and the exhaust valve
clearance is .0025" to .0045" [0,0635 a
0,1143
mm.].

Excessive
clearance
between
the valve
stems
and
guides
will
cause improper seating and burned
valves. When there is a tendency to draw oil vapor
through the guide causing excessive oil consump­ tion, fouled
spark
plugs, and poor low-speed per­
formance. To check the clearance of the valve stem
to the valve guide, take a new valve and place in
each valve guide.
Check
the clearance with a
suitably mounted
dial
indicator or feel the clearance by moving the valve stem back and forth. If this
check shows excessive clearance it
will
be necessary to replace the valve guide.
D-58.
Refacing Valves

Re
face the valves with a valve refacer. The valve

refacer
manufacturer's instructions should be fol­
lowed carefully to ensure a valve face concentric

with
the valve stem. Reface both intake and ex­
haust valves to an angle of 46°.
Take
off only the
minimum
of metal required to clean up the valve faces.

If
the thickness of the
edge
of the valve head is
reduced to
less
than
J^>"
[0>8 mm.] replace the valve.

Note:
Cocked or deformed valve springs or im­

properly
installed or missing locks can be responsible
for valve problems.

D-59.
Valve Seat Inspection
and
Refacing

Inspect the valve
seats
for
cracks,
burns, pitting,
ridges, or improper angle.
During
any general

engine
overhaul it is advisable to reface the valve

seats
in both the cylinder block and head regardless
of their condition. If the valve
guides
are to be re­ placed, this must be
done
before refacing the valve
seats.
Note
that later
engines
have hardened
exhaust valve seat inserts.

Valve
seat inserts must be concentric with finish

ream
of valve stem
guides
(exhaust) within .002"
[0,051
mm.] total indicator reading.

When
necessary to reface the valve seats, use a
valve seat grinder in accordance with the grinder
manufacturer's
instructions. Any grinding of valve

seats
should be preceded by touching up the
grinding
stone
so that their angles are accurate and
the
stone
is not
clogged.
Grind
each valve seat to

a
true 45° angle. Never grind any more than is necessary to clean up pits, grooves, or to correct
the valve seat runout.
Check
the valve
seats
with
10465

FIG.
D-20—VALVE
WITH
ROTO
CAP
FIG.
D-21—GAUGING
VALVE
SEATS

55