1953 JEEP CJ check engine

HURRICANE
F4
ENGINE

D-1.
GENERAL

This
section describes service and repair of the
F4
engine. The
engine
code
number shown in Fig.
A-3
is provided to identify the four cylinder engine.
The
meaning of the coded letters and numbers that

are
stamped on the water pump boss, at the front of the cylinder block, is given below.
Letter
to
Designate
Market

M
—
Military
E
—
Export

D
— Domestic
I
—
Industrial
&
Marine

Letter
to
Designate
Engine
Letter
to
Designate
Year
Built
R
— 1969

S
— 1970

T
— 1971
U—
1972

V
— 1973

W
— 1974

Numbers
to Designate
Compression
Ratio

F
— F4-134
Engine
63
67
•

71
-
6.3 to 1

•
6.7 to 1

-
7.1 to 1

Market
-
D
S F

(Domestic)

(1970)

Engine-
EXAMPLE

123 A B S
(F4-134)

Day- "L

Compression
Ratio

(6.7)
-
Service Engine (S)
Short
Block
(R)

-.010*
Oversize Pistons

(123rd)
-.010*
Undersize
Main

and
Rod Bearings
All
disassembly and assembly procedures are
presented 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 Section

F-l.
D-2.
Description

The
Hurricane
F4-134
engine
is an F-head, four-
cyiinder
engine
of combination valve-in-head and valve-in-block construction.
Large
intake valves
mounted in the head allow
rapid,
unobstructed
flow of fuel and air to the combustion chambers through short, water-jacketed intake passages.The
intake valves are operated by push rods through

rocker
arms. The exhaust valves are mounted

in
the block with through water jacketing to provide
effective
cooling. The exhaust valves are
operated by conventional valve tappets.
The
engine
is pressure lubricated. An oil pump

driven
from the camshaft forces the lubricant
through oil channels and drilled passages in the

crankshaft
to efficiently lubricate the main and
connecting rod bearings.
Lubricant
is also force
fed to the camshaft bearings, rocker arms, timing
gears, etc.
Cylinder
walls and piston pins are

lubricated
from spurt
holes
in the "follow" side of
the connecting rods.
Circulation
of the coolant is controlled by a
thermostat in the water
outlet
elbow cast as part
of the cylinder head.

The
cylinder head assembly when installed on the

engine
consists of the inlet valve guides, inlet valves, inlet valve springs, rocker arm and shaft assemblies, spark plugs, temperature indicator
fitting, water
outlet
fitting, and other assembled

parts.
The carburetor and air cleaner assembly
bolt to the top of the cylinder head. The rocker

arm
cover is attached to the top of the head to
enclose
the inlet valve mechanism.
The
engine
is equipped with a fully counterbalanced
crankshaft
supported by three main bearings. To better control balance, the counterweights are in­
dependently forged and permanently attached to
the crankshaft with dowels and cap screws that are tack-welded.
Crankshaft
end play is adjusted by
shims placed
between
the crankshaft thrust washer

and
the shoulder on the crankshaft.
The
exhaust manifold is a separate unit. The intake
manifold is cast as an integral part of the cylinder
head and is completely water jacketed.
This
con­
struction transfers heat from the cooling system
to the intake passages and assists in vaporizing
the fuel when the
engine
is cold. Therefore, there
is no heat control valve required in the exhaust manifold. Individual exhaust ports in the cylinder
block direct
gasses
into the exhaust manifold for unobstructed flow through the exhaust system.

The
pistons have an extra
groove
directly above
the top ring which acts as a heat dam or insulator.
As
is common practice with manufacturers,
some

engines
are built with oversize cylinder bores or undersize crankshaft journals. These
engines
are
considered standard as replacement parts of the

correct
sizes are supplied. Before ordering parts or
doing any work with a particular engine, it is important to check the
engine
code
number to
determine if oversize or undersize parts are re­

quired.
Definite identification is given by a letter
stamped after the
engine
code
number. See Fig.

A-5
for location. The letters used and their mean­ ings are given here:

A
— .010*
[0,254
mm.] undersize main and
connecting rod bearings.

B
— .010"
[0,254
mm.] oversize pistons.

AB
—
Combination
of A and B.

S
—
Service
engine.

R
—
Short
Block.
Detailed specifications for the
Hurricane
F4
engine

are
at the end of this section.
Torque
specifications
for
engine
service are at the end of this manual in Section U. When adjustments are necessary, refer to
these
specifications so that factory clearances

are
maintained.

D-3.
Engine Mountings

The
front of the
engine
is supported by two rubber
Text continued on
page
41. 38

'Jeep*
UNIVERSAL SERIES
SERVICE
MANUAL

D
insulator
mountings attached to the frame side

rail
brackets. The
rear
of the engine-transmission
assembly is supported by a rubber insulator
mounting under the
rear
of the transmission on
the frame center cross member.
This
cross member
is bolted to the frame side
rails
so that it can be
dropped when removing the transmission or engine-

transmission
assembly. The rubber insulators allow
free side and vertical oscillation to effectively

neutralize
engine
vibration at the source.

The
rubber
insulator mountings should be inspected
for separation and deterioration by jacking the
power plant away from the frame, near the sup­
ports. Vibration cannot be effectively absorbed by
separated or worn insulators. They should be re­ placed if faulty.

D-4.
Engine
Ground
Strap

To
be sure of an
effective
ground for the electrical

circuits,
a ground strap bridges the right front

engine
support to the chassis. The connections of this strap must be kept clean and tight for proper
operation of the electrical system.

D-5. ENGINE REMOVAL

Should
the
engine
require overhauling, it is neces­

sary
to remove it from the vehicle. The following procedure covers removal of the
engine
only.

The
engine, transmission and transfer case may be
removed as a unit by removing (in addition to the following procedure) the radiator guard and the
access plates in the floor pan.

a.
Drain
the cooling system by opening the
drain
cocks at the
bottom
of the radiator and lower right
side of the cylinder block.

b.
Disconnect the battery at the positive terminal
to avoid the possibility of short
circuit.

c. Remove the air cleaner horn from the carburetor
and
disconnect the breather
hose
at the oil filler
pipe.

d.
Disconnect the carburetor choke and throttle controls by loosening the clamp
bolts
and set
screws.

e. Disconnect the fuel-tank-to-fuel-pump line at the fuel pump by unscrewing the connecting nut.
f- Plug the fuel line to prevent fuel leakage.
g. Remove the radiator and radiator grille support

rods.

h. Remove the upper and lower radiator
hoses
by
loosening the
hose
clamps and slipping the clamps
back
on the
hose.
If so equipped, remove the heater

hoses
(one to the water pump, one to the
rear
of
the cylinder head) in the same manner.

i.
Remove the four
bolts
from the fan hub and re­

move
the fan hub and fan blades.

j.
Remove the four radiator attaching screws. Re­
move
the radiator and shroud as one unit, k. Remove the starting motor cables. Remove the

starting
motor.

I.
Disconnect the wires from the alternator or
generator. Disconnect the ignition
primary
wire
at the ignition coil.
NOTE:
ON
ENGINES EQUIPPED WITH EX­

HAUST
EMISSION CONTROL, REMOVE THE
AIR
PUMP,
AIR
DISTRIBUTION
MANI­
FOLD,
AND
ANTI-BACKFIRE (DIVERTER)

VALVE.
SEE SECTION
Fl
FOR PROCEDURE.
m.
Disconnect the oil pressure and temperature
sending unit wires at the units.

n.
Disconnect the exhaust pipe at the exhaust
manifold by removing the stud nuts.

o.
Disconnect the
spark
plug cables at the plugs

and
remove the cable bracket from the rocker arm cover stud.

p.
Remove the rocker arm cover by removing the
attaching stud nuts.

q.
Attach a lifting bracket to the
engine
using
existing head bolt locations. Be sure the
bolts
selected
will
hold the
engine
with the weight

balanced.
Attach lifting bracket to a boom hoist,

or
other lifting device, and take up all slack,
r.
Remove the two nuts and
bolts
from each front

engine
support. Disconnect the
engine
ground strap.
Remove the
engine
supports.
Lower
the
engine
slightly to permit access to the two top
bolts
on
the flywheel housing.
s. Remove the
bolts
which attach the flywheel
housing to the engine.

t.
Pull
the
engine
forward, or
roll
the vehicle back­

wards,
until the clutch clears the flywheel housing.

Lift
the
engine
from the vehicle.

D-6. ENGINE DISASSEMBLY

Engine
disassembly is presented in the sequence to be followed when the
engine
is to be completely
overhauled after removal from the vehicle. Some
of the operations of the procedure are also ap­
plicable
separately with the
engine
in the vehicle,

provided
that wherever necessary the part of the

engine
to be worked on is first made accessible by
removal
of
engine
accessories or other parts.

When
the disassembly operations are performed

with
the
engine
out of the vehicle, it is assumed,
in
this procedure, that all of the accessories have been removed
prior
to starting the disassembly

and
the oil has been drained.
In
addition to the instructions covering operations
for disassembling the
engine
out of the vehicle,

special
instructions are given to cover different
operations required when disassembly is
done
with the
engine
installed.

During
disassembly operations, the
engine
should
be mounted in a suitable
engine
repair
stand. Where

practicable,
modify or adapt an existing repair

stand
as necessary to accommodate the engine. If

an
engine
repair stand is not used, take care to

perform
disassembly operations in a manner that

will
protect personnel against an accident and the
engine
and its parts against damage.

NOTE:
If the
engine
is being disassembled because
of possible valve failure, check the valve tappet
clearance
before disassembly. Improper valve

clearance
could be the possible cause of valve

failure,
indicating a need for more frequent valve
checks and adjustments. 41

D
HURRICANE
F4
ENGINE
Note:
Check
the condition of the rubber O-rings.
Defective O-rings could be the major cause of oil
leakage into cylinders. Always discard and replace

all
O-rings removed as only new O-rings should be installed at reassembly.

D-18.
Ream
Cylinder
Bore Ridges

To
prevent breaking the piston lands, the ridge
at the top of each cylinder bore must be removed

first.
To remove this ridge, use a cylinder ridge
reamer,
as shown in Fig. D-3 following the instruc­
tions furnished by the reamer manufacturer. Use

care
not to cut below the top of the upper ring
travel
in the bore. Keep each piston top covered

with
an oil-soaked cloth to prevent cuttings from
falling
into the cylinder.

Note:
This
operation should be performed at this
time before the
engine
is rotated for the sequence

steps
following.

D-19.
Remove Oil Pan
Rotate the
engine
to the upside down position.
Remove the screws and lockwashers that attach
the oil pan to the cylinder block. Remove the oil

pan
and gasket.
Discard
the gasket.

D-20.
Remove Piston and Connecting
Rod
Assemblies
Remove the stamped locking nuts from the lower
end of each connecting rod bearing bolt. Remove
the connecting rod nuts. Remove the bearing cap evenly. Push the connecting rod and piston as­
sembly out of the cylinder block with the handle end of a hammer until the piston rings are free from
the cylinder bore. Remove the piston and connecting rod assembly

from
the top of the cylinder block. Reassemble the
connecting rod bearing cap with the bearings in
place in the rod from which it was removed. Rotate
the crankshaft and follow the same procedure until
all
the piston and connecting rod assemblies are
removed.
Pistons and connecting rod assemblies may be removed for repair with the
engine
in the vehicle after draining the cooling system, removing the

oil
pan and the cylinder head, and reaming the ridges as previously described.

D-21.
Remove
Timing
Gear
Cover

Remove the bolts, nuts, and lockwashers, that at­
tach
the timing gear cover to the engine. Remove
the cover, timing pointer, and cover gasket.
Dis­
card
the gasket. Remove the crankshaft oil seal

from
the timing gear cover and discard the seal. Remove the oil slinger and spacer from the
crank­

shaft.

D-22.
Remove
Timing
Gears

Use puller W-172 for pulling both the crankshaft
and
the camshaft gears.
With
the threaded cap-
screws supplied, adapt the puller to the crankshaft
FIG.
D-5—PULLING TIMING GEARS

1—
Puller
W-172 2—
Camshaft
Gear
gear and
pull
the gear.
With
the special hook-type

puller
bolts
that fit behind the camshaft gear
flange,
pull
the camshaft gear. Remove the Wood­

ruff
Keys.

D-23.
Remove
Front
End Plate
Remove the screws and lockwashers that attach the
front end plate to the cylinder block. Remove the
front end plate and gasket.
Discard
the gasket.
D-24. Remove
Clutch

Remove four
bolts
and lockwashers diagonally

opposite
that attach the clutch assembly to the
flywheel, leaving two
opposed
bolts
to be
loosened
alternately until the clutch spring pressure is re­
lieved.
Then,
support the clutch assembly with
one hand while removing the two remaining bolts.

For
information on disassembly, inspection, repair

and
assembly of the clutch refer to Section I. In­
structions for removing the clutch when the
engine
is in the vehicle are also given in Section I.

D-25.
Remove Flywheel

The
flywheel is attached to the crankshaft with two tapered dowel
bolts
and four special bolts.
Remove
these
attaching parts. Use a pry bar be­ tween the flywheel and the back of the
engine
and
carefully
loosen
the flywheel from the crankshaft.

If
the flywheel is to be removed with the
engine

in
the vehicle, the transmission and clutch must
first be removed as detailed in Section I.

D-26.
Remove
Crankshaft

Slide
the crankshaft thrust washer and all end-play

adjusting
shims off the front end of the crankshaft.

Pull
the two pieces of
rear
main bearing cap packing out of position
between
the side of the bearing cap

and
the cylinder block.

Note
the marks on the bearing caps and cylinder
block for bearing number and position. 44

'Jeep'
UNIVERSAL SERIES SERVICE
MANUAL

D
Remove the screws and lockwashers that attach
the main bearing caps to the cylinder block. Use
a
lifting bar beneath the ends of each bearing cap.

Be
careful not to exert too much pressure to cause
damage to the cap or
dowels
and pry the caps free.

CAUTION:
If main bearing caps are not removed
carefully
by raising both sides of each cap evenly

until
free of the dowels, the
dowels
may be bent.

A
bent main bearing cap dowel can cause misalign­ ment of the cap and resultant
rapid
bearing wear
necessitating replacement. Therefore, remove each
main
bearing cap carefully. If there is reason to
believe any of the
dowels
have been bent during
the bearing cap removal, remove them and install
new
dowels
as detailed in Par. D-34c.
Remove the upper
half
of the
rear
main bearing

oil
seal from the cylinder block and the lower
half

from
the oil seal
groove
in the
rear
main bearing

cap.
Install
the main bearing caps and bearings on
the cylinder block in their original positions.

Note;
Removal of the crankshaft may be ac­
complished only with the
engine
out of the vehicle.

D-27.
Remove
Exhaust
Valves and Springs
Access to the valve chamber is obtained by re­ moving the attaching parts and the valve spring
cover and gasket from the cylinder block. Use cloths
to block off the three
holes
in the exhaust valve
chamber to prevent the valve retaining locks falling
into the crankcase, should they be accidentally dropped.

With
a valve
/
spring compressor, compress the valve springs on
those
valves which are in the
closed position (valve seated against cylinder

block).
Remove the exhaust valve spring retainer

locks,
the exhaust valve spring retainer, and the exhaust valve spring. Close the other valves by
rotating the camshaft and repeat the above opera­
tion for the other valves in the same manner.
Lift

out all the exhaust valves and tag or place them in
a
rack
to indicate the location where each was re­moved from the cylinder block. If a valve sticks in
the guide and cannot be easily lifted out,
pull
the valve upward as far as possible and remove the

spring.
Lower
the valve and remove any carbon

deposits
from the valve stem.
This
will
permit re­ moval of the valve.

For
intake valve and spring removal, see
Par.
D-l7.

D-28.
Remove Camshaft

a.
Push the intake and exhaust valve tappets into the cylinder block as far as possible so the ends of
the tappets are not in contact with the camshaft. b. Secure each tappet in the raised position by in­
stalling a common clip-type clothes pin on the

shank
of each tappet or tie them up in the valve
chamber.

c. Remove the camshaft thrust plate attaching
screws.
Remove the camshaft thrust plate and

spacer.

d.
Pull
the camshaft forward out of the cylinder
block using care to prevent damage to the cam­
shaft bearing surfaces.
D-29.
Remove Valve Tappets
Remove the intake and exhaust valve tappets from
the
bottom
or crankshaft side of the cylinder block
after the camshaft has been removed. Tag each
tappet or place them in a marked
rack
so they may be reassembled in their original positions.

D-30.
Remove Oil
Gallery
Plugs
Remove the plug at each end of the oil gallery in the cylinder block.
This
operation is only applicable
when the
engine
is out of the vehicle and
will
allow access to the oil gallery so it may be cleaned.

D-31. ENGINE INSPECTION
AND
REPAIR
The
inspection and repair procedures detailed here­

in
are recommended to be followed when a com­
plete
engine
overhaul is to be made with the
engine

out of the vehicle. These instructions can generally be applied individually with the
engine
in the
vehicle. Wherever the procedure differs due to
the
engine
being in the vehicle, the necessary

special
instructions are provided. Inspection 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.

Important:
Before the inspection and repair pro­
cedures listed below are begun, the
engine
serial
number must be checked for the presence of
code

letters denoting undersize bearings or oversize
pistons. Refer to Par. D-2.

D-32.
Cylinder
Block

The
cylinder block must be thoroughly cleaned, inspected and repaired as detailed in the following

paragraphs.

D-33.
Cleaning

The
cylinder block may be steam cleaned or cleaned

with
a suitable solvent. A scraper is recommended
to remove
hard
deposits, except on highly finished surfaces. Special attention must be directed to the
cleaning of the oil passages, valve chamber,
crank­

case, and cylinder walls to remove all sludge,
dirt

and
carbon deposits. After cleaning, use air pressure to dry the block thoroughly.
D-34. Inspection

Examine
the cylinder block for minute cracks and

fractures.
Rusted valve springs or evidence of rust

in
the valve chamber or the cylinder walls is a
good

indication of a possible
crack
in the block,

a.
Examine all machined surfaces of the cylinder block for
burrs
and scores.
Check
for cylinder block
distortion by placing a straight
edge
along the
length of the cylinder head surface of the block.
With
a feeler
gauge,
check for clearance
between
the straight
edge
and the block, particularly be­
tween adjacent cylinders. Maximum permissible
out of line for service is .010"
[0,254
mm.] over the
full
length of the block. 45

HURRICANE
F4
ENGINE

FIG.
D-6—F4-134
ENGINE

1— Rocker Arm Shaft and Plug
2— Rocker Shaft
Lock
Screw
3—
Cylinder
Head Bolt
4— Nut
5—
Left
Rocker Arm
6— Rocker Shaft Support Stud
7— Nut
8— Rocker Arm Shaft Spring
9— Right Rocker Arm
10— Nut
11— Rocker Arm Cover Stud
12—
Plain
Washer
13— Rocker Arm Shaft Bracket
14— Intake Valve Tappet Adjusting Screw
15— Intake Valve Spring Retainer

Lock

16—
Oil
Seal
17— Intake Valve Spring Retainer
18— Intake Valve Spring
19—
Flared
Tube Connector
20— Pipe Plug H'

21—
Pipe Plug W
22—
Cylinder
Head
23— Intake Valve Push Rod
24— Intake Valve Guide
25— Intake Valve 26— Piston
27— Connecting Rod
28— Connecting Rod Cap Bolt
29— Connecting Rod Bearing Set
30—
Exhaust
Valve

31—
Exhaust
Valve Guide 32—
Cylinder
Block
33—
Cylinder
Block
Drain
Lock

34— Tappet Adjusting Screw
35—
Exhaust
Valve Tappet
36—
Crankshaft
Rear
Bearing Seal
37—
Crankshaft
Bearing Dowel
38—
Front
Bearing Set
39— Center Bearing Set
40—
Rear
Bearing Set
41—Bolt 42— Dowel
43—
Crankshaft

44—
Rear
Bearing Cap Packing
45—
Rear
Main Bearing Cap
4 6—Lockwasher
47— Bolt
48—
Lock
Nut
49— Connecting Rod Cap Nut
50— Center Main Bearing Cap
51—
Front
Main Bearing Cap
52— Screw and Lockwasher 53— Screw and Lockwasher
54—
Oil
Pump
55— Gasket
56—
Crankshaft
Shim
57—
Crankshaft
Thrust Washer
58— Gasket
59— Stud
60—
Exhaust
Valve Spring Cover 61— Gasket
62— Valve Spring Retainer Lower

Lock

63— Roto-Cap 64—
Exhaust
Valve Spring
65— Camshaft Front Bushing
66—
Timing
Gear
Oil Jet
67— Camshaft
68— Camshaft Thrust Plate
69— Spacer 70— Bolt and Lockwasher
71— Thermostat
72— Gasket 73— Water Outlet Fitting
74— Screw and Lockwasher

10675

Inspect
tapped
openings.
Repair any
damaged

threads. Replace any broken
studs.

b.
Check the cylinder
bores
for
out-of-round
and
taper to
determine
if the
bores
require
honing
or reboring. For detail information refer to Par. D-35.
c. If
there
is any reason to
believe
that
any of the main bearing cap
dowels
have
been
bent
during
bearing cap removal, install new
ones.
The
dowels
must
fit
tightly
to ensure cap
alignment
and as
they

are hardened
they
may be difficult to grip and re­

move.
To simplify the operation,
file
a
notch
on
each
side
of the
dowel
to
accommodate
a pair of
diagonal cutters. Using a
piece
of bar
stock
under the
diagonals
for
leverage,
work the
dowel
out. Be­

fore
installing a new
dowel
in the cylinder block, make sure the
dowel
hole
is clean. Start the
dowel
46

'Jeep*
UNIVERSAL
SERIES SERVICE
MANUAL

D
straight
in the hole, then tap the dowel lightly

with
a hammer until it
bottoms.

d.
When installing bearing eaps, be sure to tighten
the
bolts
evenly in each cap to
pull
it into place
without bending the
dowels
or distorting the
bearing
cap.
e. Other parts of the block which require inspec­ tion
and
possible
repair,
but which are directly
related
to other
engine
components (such as tappets, pistons, camshaft, valves, crankshaft, and

oil
pump) are covered later in this section.

D-35.
Cylinder
Bores

The
cylinder bores may be reconditioned by honing
or
reboring. Use oil-soaked rags to protect
crank­

shaft
journals
and other
engine
parts from abrasive
dust during all reconditioning operations.

Both
honing and reboring of the cylinders must be
done
carefully to fit the pistons and to obtain
specified clearances. If reboring of the cylinder bores is not required but the walls are glazed, use

a
finishing
hone
to remove the glaze. Reboring the cylinders must not be attempted unless ade­
quate facilities and experienced service technicians
are
available. The amount of material to be re­moved is determined from the original diameter
of the cylinder bores (3.125" to 3.127") [79,375 a
79,426
mm.] plus the amount of oversize in diameter
of the oversize pistons to be fitted. Pistons are
available
in the following oversizes.
.010"
[0,254
mm.] .030" [0,762 mm.] .020" [0,508 mm.] .040" [1,016 mm.}

The
largest cylinder bore
will
determine the over­
size to which all cylinders must be rebored, since the size and weight of all pistons must be uniform
to maintain proper
engine
balance. The maximum rebore should not exceed .040" [1,016 mm.] from

standard.
Measure
the cylinder diameters by making mea­
surements both parallel to and at right angles to
crankshaft
over entire piston travel and at
bottom

of cylinder. Proceed as follows:

a.
If bores are scored; if out-of-round
exceeds
.005
"
[0,127 mm.]; if diameters differ more than .005";

or
if taper
exceeds
.005
"
on diameter, it is generally
recommended that cylinders be reconditioned by
reboring
and honing to the next oversize using new
pistons of the proper size.

Note:
If reboring is performed, allow .0015"
[0,0381
mm.] for final honing.

All
cylinder bore diameters must be within .002
"
[0,0508
mm.] after reconditioning.

b.
If bore measurements are within the above

limits,
but indicate hollows or waviness, cylinders should be honed with 250 grit
stone
hone. Pump
hone
up and down in cylinder while it is rotating
to produce a satin-finish, diamond cross-hatched

pattern
approximately 30° with horizontal. Hone
only enough to correct waviness.
c. If cylinder bore correction is unnecessary, break the glaze on cylinder walls with a 250 grit
stone

hone
or with a suitable deglazing tool. Operate the
hone
or deglazer to obtain diamond cross-hatched

pattern
previously mentioned.

d.
Regardless of type of correction on cylinder
walls,
wash out bores thoroughly afterwards and
apply
a light coat of
engine
oil. If cylinders have
been rebored or honed heavily, measure cylinder
diameters again to assure proper selection of piston
size.

D-36.
Pistons, Rings, and Connecting Rods
Pistons are each fitted with three rings, two com­ pression rings and one oil control
ring.
The pistons have an extra
groove
above the top ring which acts as a heat dam or insulating
groove
to protect
against sealing of the top ring in the ring
groove

with
hard
carbon. The piston pin is secured by the lock screw.

The
pistons and connecting rods were removed from
the
engine
as assemblies. If cylinders were rebored,
new oversized pistons and rings
will
have to be in­

stalled.

Disassemble the pistons and rods. Remove the
two compression rings, the oil control
ring,
and the oil control ring expander from each piston. Do not remove the
bolts
from the lower end of the
connecting rods unless the
bolts
are damaged.
Clamp
each connecting rod and piston assembly

in
a padded bench vise and remove the piston pin

lock
screw and lockwasher. Press the piston pin
out of the piston and connecting rod.
Clean
all
carbon,
gum, and lacquer
deposits
from both the

inner
and outer surfaces of each piston, connecting

rod,
and piston pin. Use a ring
groove
cleaner or a
broken
ring filed to a sharp square
edge
to clean
the carbon from the piston ring
grooves
and the

insulator
groove. Use care not to scrape metal from
the sides of the
grooves
or make
burrs
on ring
groove
surfaces. Run a length of wire through the

oil
spray
hole
near the lower end of the connecting

rod
to clear the
hole
of hardened oil
deposits
or
foreign matter.
Carefully
inspect the pistons and
replace
any that are broken or cracked. Replace
pistons if any of the ring lands are chipped, broken,
or
rounded on the
edges;
or if the piston is scored,

scratched,
or burned so seriously that the imperfec­
tions cannot be removed with a hand honing
stone

or
crocus cloth.

Replace
the pistons as follows:

a.
After cylinder bores have been carefully checked for out-of-round and taper (Par. D-35), check fit
of each piston to cylinder bore with block and
pistons clean and dry and at approximately 70
°F.
[21°C]
by using Piston Fitting Gauge And Scale

Tool
No. C-690 as shown in Fig. D-7. Use a .003"
[0,0762
mm.] thickness
gauge
%" [19 mm.] wide.

The
piston is fitted upside down in the block to
facilitate the operation. The
gauge
must extend the
full
length of the piston on the thrust side
(opposite

side from slot in piston
skirt).
Scale should register
5
to 10 pounds [2,3 a 4,5 kg.]
pull
to remove the
thickness
gauge
from
between
cylinder
wall
and piston. Excessive
pull
indicates need for a slightly

smaller
piston or additional honing of cylinder. In­ sufficient
pull
indicates need for fitting a larger piston. 47

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

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