1953 JEEP DJ Service Manual

'Jeep'
UNIVERSAL
SERIES
SERVICE
MANUAL

Dl

13296

FIG.
Dl-5—ENGINE
LUBRICATION
AND
COOLING
PARTS

1— Bolt and
Lock
Washer
2—
Fan
Assembly
3—
Fan
and Alternator Belt
4—
Fan
Driven Pulley 5— Water Pump Assembly
6—
Hose
Clamp 7— Thermostat Bypass
Hose

8—Hex
Head Bolt
9— Water Outlet Elbow
10— Water Outlet Elbow Gasket
11— Thermostat
12— Water Pump Gasket
13— Impeller and Insert, Water Pump
14— Water Pump Seal 15— Dowel Pin % x Vfc"
16— Water Pump Cover
17— Bolt,
1/4-20
x 1"
18— Water Pump Shaft and Bearing
19—
Fan
Hub
20—
-Oil
Suction Pipe Gasket
21—
Oil
Suction Housing, Pipe and Flange
22— Bolt,
y4-20
x s/8"
23—
Oil
Pump Screen
24—
Oil
Dipstick
25—
Oil
Pan Gasket
26—
Oil
Pan Assembly
27—
Drain
Plug Gasket
28—
Drain
Plug 29— Screw and
Lock
Washer #6-18 x %
30—
Oil
Pump Shaft and Gear
31—
Oil
Pump Cover Gasket
32— Valve Bypass and Cover Assembly
33—
Oil
Pressure Valve 34— Valve Bypass Spring
35—
Oil
Pressure Valve Cap Gasket
36—
Oil
Pressure Valve Cap
37— Screw V4-20 x lVg"
38— Screw 1/4-20 x 1W' 39—
Fan
Driving Pulley
40— Hex. Head Bolt, x 1"
Dl-13.
Remove
Crankshaft
Vibration Damper

Refer
to Fig. Dl-6.
Remove cap screw and flat washer which attach

crankshaft
vibration damper to crankshaft. Tap

vibration
damper with a soft-headed hammer to remove it from crankshaft.

Dl-19.
Remove Oil Pump
Remove five screws, oil pump cover, and gasket

from
right side of timing chain cover. Remove
two oil pump gears.

D1-20.
Remove Timing Chain Cover

Refer
to Fig. Dl-6. Remove two
bolts
which attach oil pan to timing

chain
cover. Remove five mounting bolts, timing

chain
cover, and gasket from cylinder block of
engine.

Note:
Water pump must be removed from timing

chain
cover before timing chain cover is removed

from
cylinder block.
Dl-21.
Remove Crankshaft Front
Oil
Seal

Refer
to Fig. Dl-6.
Use timing cover aligner and oil seal remover
tool
J-22248 to remove oil seal.

Dl-22.
Remove Timing Chain
and
Spocket

a.
Temporarily install vibration damper (Fig.

Dl-6)
bolt and washer in end of crankshaft.
Turn

crankshaft
so sprockets are positioned with index

marks
aligned as shown in Fig. Dl-7.
This
will

make it easier to install parts. Remove vibration
damper bolt and washer; rap the wrench handle
sharply
to start the bolt without changing position
of sprockets.

Note:
It is not necessary to remove timing chain
dampers unless they are worn or damaged and

require
replacement.
b. Remove front crankshaft oil slinger.
c. Remove bolt and special washer which retain
camshaft distributor drive gear and fuel pump
eccentric at forward end of camshaft. Remove gear
and
eccentric from camshaft. 81

Dl

DAUNTLESS
V-6
ENGINE
d.
Use two large screwdrivers to alternately pry
forward the camshaft sprocket and
then
the crank­
shaft sprocket, until the camshaft sprocket is pried
from the camshaft. Remove the camshaft sprocket, sprocket key, and timing chain from the
engine;

then
pry the crankshaft sprocket from the crank­shaft.
Dl-23.
Remove Rocker Arm Cover
Refer to Fig. Dl-8.
Remove
positive
crankcase ventilator valve from right rocker arm cover. Remove four screws which attach each rocker arm cover to cylinder head.
Remove each rocker arm cover and
gasket
from cylinder head. 14198

FIG.
Dl-6—ENGINE
CRANKCASE
PARTS

1— Connecting Rod Assy.
2— —Piston Pin

3—
Piston and Pin Assy.
4—
Ring
Set 5— Connecting Rod
Bolt
and Nut
6— Connecting Rod Bearing
7— Damper Spring
8— Damper
Bolt

9—
Timing
Chain Damper (Right)

10—
Cylinder
Block

11— Camshaft
12—
Woodruff
Key
13— Camshaft Bearing (No. 1 Front) 14— Camshaft Bearing (No. 2)
15— Camshaft Bearing (No. 3) 16—
Camshaft
Bearing (No. 4
Rear)
31-
17—
Camshaft
Plug
(Rear)
32-18—
Flywheel
33-
19—
Ring
Gear
34-
20— Crankshaft Bearing Set 35-
21—
Main
Bearing Oil Seal
(Rear)
36-
2 2—Crankshaft 3 7-
23—
Main
Bearing Packing Oil Seal
(Rear)
28-
24— Bearing Cap
Bolt
39-
25— Woodruff Key 40-
26—
Timing
Chain Damper
(Left)
41-
27— Damper Bolt 42- 28—
Timing
Chain
43-
29—
Camshaft
Sprocket 44-
30— Crankshaft Sprocket
—Crankshaft
Slinger

—Crankshaft
Shedder

—Crankshaft
Packing (Front)

—Timing
Gear
Cover Gasket

—Timing
Gear
Cover

—Vibration
Damper

-Bolt

-Washer

-Bolt

—Dowel Pin

-Camshaft
Thrust
Retainer and Bolt

—Washer

-Distributor
Drive
Gear

—Fuel
Pump Eccentric
82

'Jeep'
UNIVERSAL
SERIES SERVICE
MANUAL

Dl

14028
j

FIG.
D1-7—TIMING
CHAIN
AND
SPROCKET ALIGNMENT 1—
Camshaft Sprocket

2—
Crankshaft
3—Timing
Chain

Timing
Marks
Dl-24.
Remove
Cylinder
Head Assembly

a.
Unscrew, but do not remove, three
bolts
(Fig.

Dl-8)
which attach rocker
arm
assembly to cylinder
head.
Remove rocker arm assembly, with bolts,

from
cylinder head. See Section F2 for
engines

equipped with exhaust emission control.
b. Remove
eight
cylinder head bolts, cylinder head,

and
gasket from cylinder block.

Dl-25.
Remove Push Rod and Valve
Lifter

Refer
to Fig. Dl-8. Remove push rods and valve lifters from the
cylin­

der
block.
Mark,
or otherwise identify, each valve

lifter
according to its cylinder and valve position.

Note:
If valve lifters are not to be serviced, cover
valve lifters and camshaft with a clean cloth to
protect them from dirt

Dl-26.
Remove Camshaft

Refer
to Fig. Dl-6.

Carefully
withdraw camshaft forward from bear­
ing bores; avoid marring the bearing surfaces. Re­

move
camshaft from cylinder block.

Dl-27.
Remove Flywheel Housing and
Clutch

a.
If flywheel housing and clutch was not pre­
viously removed, remove six mounting
bolts
and
flywheel housing from cylinder block.
b.
Mark
clutch cover and flywheel to assure that
clutch
will
be installed in identical position when

engine
is assembled.
c. Remove six attaching screws and clutch assem­
bly from flywheel.
D1-28. Remove Flywheel

Refer
to Fig. Dl-6.
Remove six attaching
bolts
and flywheel from

engine
crankshaft.

Dl-29.
Remove Oil Pan

Refer
to Fig. Dl-5.

To
gain access to oil pan mounting bolts, invert
the
engine.
Remove mounting bolts, oil pan, and gasket from
engine
cylinder block.

Dl-30.
Remove Oil Pump Intake Pipe and Screen

Refer
to Fig. Dl-5.
Remove two attaching screws, and oil pump intake
pipe and screen assembly from
engine
cylinder block.

Dl-31.
Remove Piston and
Connecting
Rod Assembly

a.
Examine the cylinder bores. If bores are worn
so that shoulder or ridges exist at the top of piston

ring
travel, remove the ridges with a ridge reamer.
FIG.
Dl-8-

-CYLINDER HEAD,
AND COVER
ROCKER
ARM
1—
—Right
Rocker
Arm
Cover

2—
Rocker
Arm
Cover
Bolt

3—
Gasket

4—
Bolt
5—
Baffle
6—
Left
Rocker
Arm
Cover
7—
Rocker
Arm Shaft
8—Plug
9—
Rocker
Arm Spring
10—
Cylinder
Head
11—
Head
Gasket

12—
Push
Rod

13—
Valve
Lifter
14—
Intake
Valve

15—
Exhaust
Valve

16—
Dowel
Pin
17—
Valve
Spring 18—
Valve
Spring Cap
19—
Valve
Spring Cap Key

20—
Cotter
Pin
21—
Rocker
Arm Shaft End Washer

22—
Rocker
Arm Shaft Spring

23—
Rocker
Arm
24—
Rocker
Arm Shaft
Bracket

25—
Bolt
83

Dl

DAUNTLESS
V-6
ENGINE
This
will
prevent damage to piston rings or
crack­

ing piston lands during removal.
b. Use a silver pencil or quick-drying paint to mark
the cylinder number on all pistons, connecting rods,
and
caps. Starting at the front end of the crankcase,
the cylinders in the right bank are numbered 2-4-6
and
in the
left
bank are numbered
1-3-5.

c. Remove cap and lower connecting rod bearing

half
from No. 1 connecting rod.

d.
Push the piston and rod assembly away from
the crankshaft and remove it from top of cylinder bore. Then install cap and lower bearing half on
connecting rod.
e. Remove each connecting rod and piston as­ sembly as described in c and d, above.
FIG.
D1-9—CRANKSHAFT
MAIN
BEARING
CAPS

1—Thrust
Bearing
D1-32.
Remove
Main
Bearing and Crankshaft
a.
This
engine
has four crankshaft main bearings.

Front
to
rear,
they are numbered 1 to 4. Refer to

Fig.
Dl-9. With a silver pencil or quick-drying
paint, mark the bearing number on each main bearing cap.
b. Remove two
bolts
which secure first (front)

main
bearing cap to
engine
cylinder block. With

a
lifting bar, carefully pry the cap from the crank­ shaft and block. Be careful not to damage the cap,
block or crankshaft. Remove the bearing cap, with
lower main bearing half, from the cylinder block.

Keep
bearing half and cap
together.
Similarly, remove the next two main bearing caps with lower

main
bearing halves. To remove
rear
main bearing
cap,
use
rear
main bearing remover bolt W-323.
c. Remove the fabric seal from inside diameter of
fourth (rear) main bearing cap, and remove neo-
prene composition seal from outer surface of this
bearing cap. Discard both seals.

d.
Lift
and remove the crankshaft from
engine
cylinder
block. Do not remove upper main bearing
halves from block or lower main bearing halves

from
caps at this time. Mount main bearing caps

in
their original positions.
Dl-33.
ENGINE
CLEANING,
INSPECTION,

AND
REPAIR

The
cleaning, inspection, and repair procedures
detailed herein are recommended to be followed
when a
complete
engine
overhaul is to be made
with the
engine
out of the vehicle. These instruc­
tions
can generally be applied individually with the

engine
in the vehicle. Wherever the procedure dif­
fers due to the
engine
being in the vehicle, the necessary special instructions are provided. Inspec­
tion and repair instructions are included to cover
the cylinder block, cylinder head, crankshaft and bearings, connecting rods and bearings, oil pump,
valves and tappets, pistons and rings, flywheel,
timing gears, and the camshaft and bearings. In
addition, fitting operations for
these
engine
com­

ponents
are included.

D1-34.
Cylinder Block

The
cylinder block must be cleaned thoroughly, inspected, and repaired as necessary, as described
below.

Dl-35.
Cylinder Block Cleaning
Steam-clean the cylinder block, or clean it with

a
suitable cleaning solvent A scraper can be used
to remove
hard
deposits, but do not score machined
surfaces. Be certain that oil passages, valve cham­

bers,
crankcase, and cylinder walls are free from sludge, dirt, and carbon deposits. After cleaning,

dry
the cylinder block carefully with compressed
air.

Dl-36.
Cylinder Block Inspection

a.
Inspect cylinder walls visually for scoring,
roughness, or ridges which indicate excessive wear.
Check
cylinder bores for taper and out-of-round
with an accurate cylinder
gauge.
Measure eact bore at top, middle and bottom, both parallel tc
and
at right
angles
to the centerline of the
engine

The
diameter of the cylinder bores at any poin
FIG.
Dl-10—MEASURING
CYLINDER
BORE

1—Telescope Gauge [90*
From
Piston Pin]
84

'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
Dl-38.
Crankshaft
Cleaning

Clean
the crankshaft thoroughly with a suitable
cleaning solvent.
Clean
drilled oil
passages
in its

journals
with a small rifle brush to remove all
sludge
or gum deposits; dry
passages
with com­
pressed air.

Dl-39.
Crankshaft
Inspection
and
Repair

If
the crankshaft has not
been
removed from the

cylinder
block for inspection, disconnect two con­ necting rods at a time from crankshaft. Inspect
the bearings and crankpin journals. While turning
crankshaft,
it is necessary to temporarily reconnect
the rods to crankshaft to avoid possibility of dam­ aging the journals through contact with uncon­
nected rods.
Inspect the crankpins visually for excessive or ir­

regular
wear, and for scoring. Use an
outside
micrometer to check crankpins for out-of-round.
Standard
crankpin
diameter is
2.0000"
[5,080
cm.].

If
crankpins are more than .0015"
[0,0381
mm.]
out-of-round, new bearings cannot be
expected
to
have satisfactory life.
If
the crankshaft has
been
removed from the
cyl­

inder
block for inspection support it on V-blocks
at its main bearing journals 1 and 4. Inspect the

main
bearing journals visually for excessive or ir­

regular
wear, and for scoring. Standard main bear­
ing
journal
diameter is 2.4995"
[6,349
cm.].
Total

indicator readings at each
journal
should not ex­
ceed .003"
[0,076
mm.].

Check
run out at all four journals and
note
high
spot
(maximum eccentricity) of each
journal.
High

spot
of each
journal
should
come
at the same
angular
location. If high
spots
do not coincide,

crankshaft
is misaligned and unsatisfactory for
service.

If
crankpin or main bearing journals are scored,
ridged, or out-of-round, the crankshaft must be replaced or reground to a standard undersize bear­
ing diameter to ensure satisfactory life of bearings. Slight roughness can be removed with a fine grit
polishing cloth thoroughly
wetted
with
engine
oil.
Burrs
can
be
honed with a fine oil
stone,
so long as
bearing clearances
will
remain within specified
limits.

Dl-40.
Crankshaft
Main
Bearings

A
crankshaft bearing consists of two halves which
are
neither alike nor interchangeable. One half is

carried
in the corresponding main bearing cap; the
other half is located
between
the crankshaft and

cylinder
block. The upper (cylinder block) half
of the bearing is grooved to supply oil to the con­ necting rod bearings, while the lower (bearing cap)

half
of the bearing is not grooved. The two bearing
halves must not be interchanged. All crankshaft
bearings
except
the thrust bearing and the
rear

main
bearing are identical. The thrust bearing (No. 2) is longer and it is flanged to take
crank­

shaft end thrust. When the bearing halves are
placed in cylinder block and bearing cap, the
ends
extend slightly beyond the parting surfaces. When
cap
bolts
are tightened, the halves are clamped
tightly in place to ensure positive seating and to
prevent turning. The
ends
of bearing halves must never be filed flush with parting surface of
crank­

case or bearing cap.

Crankshaft
bearings are the precision type which
do not require reaming to size or other fitting.
Shims
are not provided for adjustment since worn
bearings are readily replaced with new bearings of proper size. Bearings for service replacement are

furnished
in standard size and undersizes. Under no circumstances should crankshaft bearing caps
be filed to adjust for wear in old bearings.

Dl-41.
Crankshaft
Main
Bearing
Cleaning
and
Inspection

Clean
main bearing surfaces. Inspect the bearings

visually
for excessive or uneven wear, scoring, and

flaking.
Visibly worn or damaged bearings must
be replaced. It is necessary to check
radial
clear­ ance of each new or used crankshaft main bearing
before installation.
This
can be
done
by either of two methods, which are described in
Pars.
Dl-42

and
Dl-43.

a.
The desired
radial
clearance of a new bearing
is .0005" to .0021"
[0,0127
a
0,0534
mm.].
b. Replacement bearings are furnished in standard
size, and in several undersizes, including undersizes
for reground journals. If a new bearing is to be installed, try a standard size; then try each under­
size in turn until one is found that
meets
the
specified clearance limits.

Note:
Each
undersize bearing half has a number
stamped on its outer surface to indicate amount of undersize. Refer to Fig. Dl-12. 14288

FIG.
Dl-12—LOCATION
OF
UNDERSIZE
MARK
ON
BEARING
SHELL

1—
Tang

2—
Undersize
Mark
Dl-42.
Main
Bearing
Fitting,
Plastigage

Bearing
clearance can be checked by use of Plasti­
gage,
Type PG-1 (green) which has a range of
.001" to .003" [0,025 a
0,076
mm.]. Refer to

Fig.
Dl-13.

a.
Place a piece of Plastigage lengthwise along the
bottom
center of the lower bearing half, then 86

'Jeep'
UNIVERSAL
SERIES SERVICE
MANUAL
Dl
A 8

j
13415

FIG.
Dl-13—USING
PLASTIGAGE
TO
MEASURE
BEARING CLEARANCE

1— Plastigage
A—Start

2—
Scale
B—Flattened

install
cap with shell and tighten
bolts
80 to 110 lb-ft. [11,1 a 15,2 kg-m.] torque.

Caution:
Do not turn crankshaft with Plastigage

in
bearing.

b.
Remove bearing cap with bearing half. The
flattened Plastigage
will
adhere either to the bear­ ing half or the
journal.
Do not remove it.
c. Using the scale printed on the Plastigage en­

velope,
measure Plastigage width at its widest
point. The number within the graduation which
most
closely corresponds to the width of Plasti­
gage
indicates the bearing clearance in thousandths
of an inch.

DI-43.
Main Bearing
Fitting,
Feeler or
Shim
Stock

A
small strip of feeler or shim stock can be used
to check main bearing clearance. The method is
simple, but care must be taken to avoid damage
to the bearing surface from excessive pressure against the strip.

a.
Cut a rectangular piece of feeler or shim stock, .001"
[.0254
mm.] thick,
i/2"
[12,70
mm.] wide, and
Vs"
[3,175 mm.] shorter than the bearing width.
Position the bearing cap to the crankshaft journal
and
cylinder block, and install two cap
bolts
loosely.

b.
Tighten alternate cap bolts, a little at a time,

until
both have
been
tightened to 35 to 45 lb-ft. [4,8 a 6,2 kg-m.] torque.
c.
Turn
the crankshaft by hand, no more than one

inch
[2,5 cm.] in either direction.

Caution:
If the crankshaft is turned too far, it
will

embed the strip in the bearing surface.
This
will
damage the bearing and also cause a false indica­tion of bearing clearance.

If
bearing clearance is correct, the strip should cause a light to heavy drag, or resistance to rotation.
If
there is little or no drag, clearance is too great;

if
the crankshaft cannot be turned, clearance is
insufficient. In either case, a different main bear­ ing must be
selected
to obtain proper clearance.

d.
Repeat
steps
a, b, and c, as necessary, to
select

proper main bearing size. After a bearing has
been

selected, remove the
test
strip from bearing on
crankshaft
journal surface; wipe both surfaces care­

fully,
and apply clean
engine
oil to both surfaces. Position the bearing cap to the crankshaft journal

and
cylinder block, and install two cap
bolts
loosely.

Tighten
alternate cap bolts, a little at a time, to

final
specified torque of 80 to 110 lb-ft. [11,1 a 15,2 kg-m.]. The crankshaft should now rotate
freely.

Dl-44.
Piston
and
Connecting
Rod
Disassembly

a.
Remove two compression rings with a piston
ring
expander. To remove oil ring, remove the two

rails
and spacer-expander, which are separate
pieces

in
each piston third
groove.

b.
From
Tool Set W-338 use support base J-6047-1
with collar J-6047-5 and driver J-6047-4 with an
arbor
press to press piston pin from piston and con­
necting rod. Mount support base and collar in press. Set driver in position and press out pin. Refer to

Fig.
Dl-14.
FIG.
Dl-14—PISTON
PIN
REMOVAL

1—
Arbor
Press

2—
Driver

3—
Piston
and Rod Assembly
4—
Collar
•
5—Support Base Dl-45.
Piston
and
Connecting
Rod
Cleaning
and Inspection

a.
Clean
carbon from piston surfaces and under­
side of piston heads, and remove all pistons rings.
Clean
carbon from ring
grooves
with a suitable tool.
Remove any gum or varnish from piston skirts with a suitable solvent.

b.
Carefully examine pistons for rough or scored
bearing surfaces, cracks in
skirt
or head, cracked

or
broken ring lands, chipping and uneven wear 87

Pi

DAUNTLESS
¥-6
ENGINE
which
would cause rings to seat improperly or have
excessive clearance in
ring
grooves. Damaged or
faulty
pistons should be replaced,
c.
Inspect bearing surfaces of piston pins and check

for
wear by measuring worn and unworn surfaces

with
a micrometer. Rough or worn pins should be
replaced.
Test fit the piston pins in piston
bosses.
Occasionally,
a pin
will
be tight due to gum or

varnish
deposits.
This
may be corrected by remov­

ing
the deposit with a suitable solvent. If piston
bosses
are worn out-of-round or oversize, the piston

and
pin assembly must be replaced. Oversize pins
are
not
practical,
since the pin must be a press fit
in
the connecting rod bore. Piston pins must fit the
piston with an easy finger push at
70°F.
[21°C.].

They
should have .0004" to .0007"
[0,0178
a
0,0102
mm.] clearance.

Dl-46.
Piston Fitting

If
cylinder bores are rebored or heavily honed,
new and possibly oversize diameter pistons must be
installed.
A new piston must be fitted to its cylinder

bore.
A satisfactory method of fitting pistons is as
follows.

a.
Expand
a
telescope
gauge
to fit the cylinder bore at right angles to the piston pin and
between
1
Vi"
to 2" [3,7 a 5,1 cm.] from the top.

b.
Measure diameter of the piston to be fitted, as
shown in
Fig.
Dl-15. The piston must be measured

at
right angles to the piston pin, W [6,3 mm.] below the oil
ring
groove. The piston must be be-
FIG.
Dl-15—MEASURING
PISTON

1—90°
tween .001" and .0015" [0,025 a
0,038
mm.]

smaller
than the cylinder bore.

Note:
Both cylinder block and piston must be at

very
nearly the same temperature when measure­
ments are made or
errors
due to expansion
will
occur.
A difference of 10°F.
[5,6°C]
between
parts
is sufficient to produce a variation of .0009"
[0,0023
mm.].

The
pistons are cam-ground, which means that the
diameter at a right angle to the piston pin is
greater
than the diameter
parallel
to the piston

pin.
When a piston is checked for size, it must be
measured
with a micrometer applied to the
skirt

along a line
perpendicular
to axis of the piston pin.

Dl-47.
Piston Ring Fitting

When
new piston rings are to be installed without

reboring
cylinders,
the glazed cylinder walls should
be slightly dulled. However, cylinder bore diameter
should
not increase more than necessary.
Cylinder

walls
should be honed with the finest grade of
stone
to remove any glaze.
New compression rings must be checked for clear­ ance in piston
grooves
and for gap in cylinder bores;
however, the flexible oil rings are not checked for gap. The cylinder bores and piston
grooves
must
be clean, dry, and free of carbon and
burrs.

With
rings installed on piston, check clearance in
grooves
by inserting feeler
gauge
between
each
ring

and
its lower
land.
Any
ring
groove
wear
will
form

a
step
at inner portion of the lower
land.
If the
piston
grooves
have worn enough that relatively

high
steps
exist on the lower lands, the piston
should
be replaced because the
steps
will
interfere

with
proper operation of new rings and the
ring
clearances
will
be excessive. Piston rings are not

furnished
in oversize widths to compensate for
ring
groove
wear.

When
fitting new rings to new pistons, the side

clearance
of the compression rings should be .002" to .0035"
[0,051
a
0,089
mm.] for number one (1)

ring,
.003" to .005" [0,076 a 0,127 mm.] for number
two (2)
ring,
and side clearance of the oil
ring
should
be .0015" to .0085" [0,038 a
0,220
mm.].

To
check the end gap of a compression
ring,
place

it
in the cylinder in which it
will
be used, square

it
in the bore by tapping with the lower end of
a
piston, then measure the gap with a feeler
gauge.

A
compression
ring
should not have
less
than .015"
[0,381
mm.] gap when placed in cylinder

bore.
If gap is
less
than specified value, file the
end of the
ring
carefully with a fine file to obtain

proper
gap.

Dl-48.
Piston and Connecting Rod Assembly

Note:
A connecting rod can spring out of alignment

in
shipping or handling. Always check a new con­
necting rod for misalignment before installing pis­
ton and pin.

a.
If a new connecting rod is to be installed, check
its alignment with an accurate rod alignment fix­

ture.

b.
If the piston and connecting rod assembly is
to be installed in the left cylinder bank, it must be assembled as shown in
Fig.
Dl-16. If the piston and
connecting rod assembly is to be installed in the
right
cylinder bank, it must be assembled as shown
in
Fig. Dl-17.
Note
that
these
two assemblies are

mirror-images
of each other.

c.
Lubricate
piston pin to avoid damage when

pressing
through the connecting rod.

d.
To install piston pin in piston and connecting

rod,
use
Tool
Set W-338.
Install
collar J-6047-5,
spring
J-6047-3, and pilot J-6047-20 into the base

support
J-6047-1 and place in
arbor
press. Using

driver
J-6047-4 press piston pin into piston and 88