1971 FIAT 500 Controls

The interior of the car can be heated by the engine
warmed air being ducted into the front compartment and
controlled by a lever on the heating system tunnel.
Engine ignition is by a battery, ignition coil and distribu-
tor which is driven by a gear on the camshaft. The engine
is started by an electric starter motor which is mounted on
the gearbox casing and is controlled by a lever located
behind the gearchange lever.
The complete power unit is mounted by a spring support
at the centre of the rear b o d y crossmember and by t w o
rubber pads mounted laterally to the gearbox.
1 :2 Engine removal (sedan—all versions)
To remove the engine from the car proceed as follows:
Raise t h e rear of t h e car and place on firmly based
stands placed under suitable brackets on the underside
of the body.
Disconnect the battery positive terminal clamp from the
battery terminal post. Release the clip securing the main
petrol pipe to the tank sender unit and ease t h e pipe
from the unit. Drain the oil from the engine sump into
a suitably sized container.
D i s c o n n e c t t h e rear number plate light wire (see
FIG 1 : 6) . Release t h e engine compartment lid check
strap from its slot and separate the lid from the body by
sliding the hinge apart.
Remove the cables attached to the ignition coil, also
to the generator and the starter motor. Remove the
starter motor control tie rod.
Release the oil pressure
indicator cable, the main petrol pipeline at the pump,
the accelerator and starting device controls.
Remove the t w o hoses of the heating and cooling
system which are the input hose to the blower and the
hose for the car heating system. Release and lift out the
engine apron. Remove the starter motor mounting bolts
and carefully lift away the motor.
Using a garage hydraulic jack with suitable cradle (see
FIG 1 : 7) or a rope sling relieve the engine weight
from its mountings. Remove the nuts securing the
gearbox to the engine and the flywheel protection
apron.
Remove the bolts fixing the elastic support to the cross-
member. Remove the rear crossmember mounting nuts
noting that the engine earth cable is held by one
mounting nut and lift away the crossmember.
Carefully ease t h e engine away from the gearbox
ensuring that there is no strain placed on the clutch
shaft. Lower the engine to the floor taking care that no
weight is allowed on any of the attachments. 1
2
3
4
5
6
7
8
1 :3 Engine removal (station wagon)
To remove the engine from the station wagon proceed
as follows:
1 Raise t h e rear of the vehicle and place on firmly based
stands placed under suitable brackets on the underside
of the body.
2 Disconnect the battery positive terminal clamp from
the battery terminal post. Release the clip securing the
main petrol pipe to the tank sender unit and ease the
pipe from the unit. Drain the oil from the engine sump
into a clean dry container of suitable size.
3 H o l d t h e rear door open and secure using string to stop
it swinging to the closed position. Secure the luggage
compartment floor panel in its upright position.
F50013 4 Remove the cables attached to the ignition coil, also
to the generator and starter motor. Remove the starter
motor control tie rod. Release the o i l pressure indicator
cable, the main petrol pipeline at the pump, the accele-
rator and starting device controls. Disconnect the air
filter housing.
5 Remove the hose connecting the car heating system
to the engine cowling. Disconnect the clip holding the
air pipe to the blower and carefully disconnect the pipe
from the blower cowling. Remove the starter motor
mounting bolts and carefully lift away the motor. FIG 1:5 120.000 engine assembly: cross-section view
through a cylinder

Cylinder head installation:
To refit the cylinder head proceed as follows:
Place a new cylinder head joint on the cleaned faces of
the cylinder barrels. Insert the rocker pushrod and
lubrication pipe sleeves together with the relevant
gaskets and rings.
Fit the washers and nuts to the studs and tighten to
fingertight.
Tighten the nuts in the order shown in FIG 1 :44 and
FIG 1 :46 to a torque wrench setting of 18.1 Ibft. Reset
the torque wrench to a new setting of 23.9 Ibft and
tighten the nuts once more in the recommended order.
Replace the pushrods in the correct order.
Refit the rocker shaft ensuring correct location of the
lubrication tube to the rocker shaft and replace the
plain and lockwashers. Tighten the nuts to a torque
wrench setting of 15.2 Ibft. Reset the tappet to rocker
clearance adjustment.
Connect the t w o exhaust side manifolds to the cylinder
head. Using new gasket refit the spark plugs and HT
cables. Replace the rocker cover fitted with a new cork
gasket and blower conveyor to the cylinder head
securing screws. Refit the carburetter and reconnect its
fuel line and controls. Refit the air cleaner and elbow
and connect the rocker cover breather pipe (if fitted).
1
2
3
4
5
1 :7 Timing gear overhaul
Camshaft:
The cast iron camshaft is located in the crankcase and is
supported at either end in sets machined directly in the
crankcase. No bushes are used. The camshaft is driven by
a chain from the crankshaft at half engine speed and
operates the overhead valves through tappets, pushrods
and rockers (see
FIG 1 :20).During engine overhaul the camshaft journals and cam
faces should be free of score marks or signs of seizure and
have a bright mirror finish.
The distributor drive gear should be inspected for tooth
wear which if excessive means that the camshaft must be
replaced.
Tappets:
The tappets should be inspected for signs of seizure or
excessive wear. The end surface that is in contact with the
camshaft should be smooth without signs of excessive
wear. Any slight scratches or indentations may be
removed using a very fine oil stone.
Pushrods and sleeves:
The pushrods operate in special axially resilient sleeves
that are compressed on assembly between the cylinder
head and the crankcase. It is through these sleeves that
the engine sump is vented also through which the oil
returning from the cylinder head passes.
Two rubber O-ring seals are fitted to each sleeve to
ensure an oil t i g h t seal between the cylinder head and
crankcase. The sleeves should be checked for distortion
and exact equal length and when refitting new seals must
always be fitted.
The pushrods should be checked for straightness and
the t w o ends that contact the rocker setscrew and the
F50019
The crankcase is an aluminium casting suitably ribbed
to ensure correct air cooling. The main bearing and cam-
shaft bearing bores are machined as also are the tappet 1 :8 Crankcase and cylinders During valve gear overhauls the clearance between the
rocker shaft bore and the rocker must be checked. The
maximum permissable wear between these t w o parts is
.0059 inch. It is recommended that the part which is most
worn be renewed, or in extreme cases both parts. Rocker and rocker shaft: tappet seat must not show any signs of roughness or
excessive wear. 3 Oil shield (for intake valves only) 4 Snap ring
5 Rocker 6 Upper spring cup 7 Valve spring
8 Lower spring cup 9 Pushrod 10 Tappet
11 Oil seal ring 12 Pushrod sleeve 13 Seal ring 1 Intake valve 2 Upper cup lock Key t o Fiq
1 :20 FIG 1:20 Valve, pushrod and tappet assembly FIG 1:19 Camshaft. The arrow points to the lube oil
outlet port

FIG 2:5 Starting device (choke) diagrammatic section
KeytoFig2:5 A Device fully inserted B Device partially inserted C Device disinserted 2 Air inlet 16 Bowl
19 Throttle 21 Primary venturi 24 Secondary venturi 26 Mixture duct 27 Mixture leaning air orifice
28 Transition duct 29 Transition mixture orifice 30 Starting mixture orifice 31 Transition orifice
32 Starting mixture orifice 33 Starting valve 34 Mixture duct 35 Starting device air orifices 36 Rocker
37 Lever return spring 38 Starting device control lever 39 Control wire screw 40 Cover with support for starting
device control bowden 41 Starting valve spring 42 Spring casing. 43 Starting jet emulsion air orifice
44 Air emulsion reserve well orifice 45 Starting reserve well 46 Starting jet
F50037
FIG 2 : 4 Diagrammatic section of Weber 26.IMB
carburetter
KeytoFig2:4 1 Air corrector jet 2 Air inlet
3 Idle speed mixture duct 4 Idle speed jet holder
5 Idle speed air orifice 6 Filter cover 7 Filter
8 Fuel inlet connection 9 Needle valve seat 10 Needle
11 Float pivot 12 Float 13 Idle speed jet
14 Main jet holder 15 Main jet 16 Bowl
17 Idle speed mixture adjustment screw 18 Idle speed
mixture orifice 19 Throttle 20 Transition hole
21 Primary venturi (not interchangeable) 22 Emulsion
orifices 23 Emulsion well 24 Secondary venturi
(not interchangeable) 25 Main nozzle
design with a 1.0236 inch diameter throat measured at the
height of the throttle shaft. The amount of charge passing
to the manifold is controlled by a throttle butterfly valve
from an accelerator pedal operating a lever secured to the
throttle valve shaft via a cable. The carburetter is fitted with
a progressive action starting device which enables the
driver to suit the mixture richness to the most arduous of
starting conditions, and will enable the engine to run
evenly until it reaches its normal operating temperature.
A dampened needle valve ensures a smooth running
engine as it is not affected by engine vibrations and there-
fore giving a constant fuel level in the carburetter bowl. A
secondary venturi is incorporated in the single casting of
the carburetter body and this has a diameter of 0.8268 inch.
Carburetter operation:
Filtered air flows through the venturi 24 (see FIG 2 :4)
where it mixes w i t h fuel flowing from the nozzle 25 and
the charge is then conveyed to the cylinders through the
primary venturi 21 and throat, where the throttle butterfly
19 controls the amount of charge.
Petrol flows from the main fuel line to the bowl 16
through a gauze filter 7 and needle valve 10, where the
float 12 pivoting at point 1 1 , controls the opening of the
needle 10 so maintaining a constant fuel level. From the
bowl 16 fuel reaches the emulsion well 23 via the metered
main jet 15 where, after having been mixed with the air
coming from the metered air corrector screw 1, through
the emulsion orifices 22 and spray nozzle 25, it finally
reaches the Venturis where it mixes w i t h the air stream

2:12 Fault diagnosis
(a) Leakage or insufficient fuel delivered
1 Air vent in tank restricted
2 Petrol pipes blocked
3 Air leaks at pipe connections
4 Pump or carburetter filters blocked
5 Pump gaskets faulty
6 Pump diaphragm defective
7 Pump valves sticking or seating badly
8 Fuel vapourizing in pipelines due to heat
(b) Excessive fuel consumption
1 Carburetter needs adjusting
2 Fuel leakage
3 Sticking controls or choke device
4 Dirty air cleaner
5 Excessive engine temperature
6 Brakes binding
7 Tyres under-inflated
8 Idling speed too high
9 Car overloaded(c) Idling speed too high
1 Rich fuel mixture
2 Carburetter controls sticking
3 Slow-running screws incorrectly adjusted
4 Worn carburetter butterfly valve
(d) Noisy fuel pump
1 Loose mountings
2 Air leaks on suction side and at diaphragm
3 Obstruction in fuel pipe
4 Clogged pump filter
(e) No fuel delivery
1 Float needle stuck
2 Vent in tank blocked
3 Pipeline obstructed
4 Pump diaphragm stiff or damaged
5 Inlet valve in pump stuck open
6 Bad air leak on suction side of pump
46

lubricated using Fiat Jota 3 grease.
1 Pressure plate—boss outer faces.
2 Clutch cover—withdrawal lever fulcrum.
3 Withdrawal lever stopnuts—contact face.
4 Withdrawal lever carrier ring — lever contact face.
5 Crankcase end pilot bushing lubricated with Fiat KG.15
grease.
6 Lubricate contact faces of driven plate and clutch shaft.
To install the clutch assembly proceed as follows:
1 Ensure t h a t there is no grease or oil on the faces of the
driven plate or flywheel face and position with the
raised part of the hub towards the transmission unit.
2 Locate Fiat tool A.70085 (diaphragm clutch) or
A . 6 2 0 2 3 (coil spring clutch) or a suitably sized drift,
through the driven plate hub and position in crankshaft
pilot bushing. Gradually tighten the clutch unit
mounting screws working diagonally and finally tighten
to a torque wrench setting of 5.8 to 7.2 Ib ft.
5 : 6 Pilot bushing
Whenever the clutch unit is being renewed or over-
hauled it is essential that the crankshaft pilot bush is
checked for excessive wear or damage. Also check that
FIG 5 : 7 Side sectional view of clutch and throw-out
mechanism - 5 0 0 Sedan (11OF), late Station Wagon. Value
1.5 mm (.059 inch) refers to the clearance to be obtained
through the adjustment of clutch throw-out yoke rod
F50063
The withdrawal mechanism comprises a forked lever
(see FIG 5 : 8), which is located in the clutch housing and 5:7 Withdrawal mechanism
New 500 and 500D models:
the spigot on the bush end is in a good serviceable con-
dition. The maximum clearance between the clutch shaft
spigot and the bush should not be greater than .0059 inch
otherwise the pilot bush must be renewed. To remove the
pilot bush use Fiat puller A.40006/1 /2 or a small universal
internal bush and bearing removal tool.
To fit a new bush use a suitably sized drift and drive the
bush fully home and lubricate well with Fiat KG.15 grease. FIG 5 : 9 Clutch controls and adjusting mechanism LEVER RETURN SPRING
ADJUSTABLETIE R O DCLUTCH RELEASE LEVER NUT A N D JAM NUT
FOR TIE R O D CLUTCH RELEASE BOWDEN FIG 5:8 Clutch throw-out mechanism
CLUTCHSHAFT
LEVER-AND-SHAFT
RELEASE
RELEASETHRUST RING
FORK-TO-THRUSTFASTENERS RING
CARBON
RING
WITHDRAWAL FORKCLUTCH

1
791011 8 234
11
10
16,15
14 13
1265
FIG 11:5 Components of starter
Key to Fig 11:5 1 Drive end head 2 Head shield 3 Frame 4 Switch 5 Commutator cover band
6 and 7 Pin and spring for lever 8 8 Starting engagement lever 9 Head shield 10 and 11 Head fixing tie rods and tubes
12 Pinion, complete 13 Starting engagement spring 14 Drive unit sleeve and free wheel hub 15 Armature
16 Commutator end head
Testing field coils:
When tested w i t h an ohmmeter the reading should be
8+.1—.3 ohms. Failing an ohmmeter use a 12-volt
supply and connect it in series w i t h an ammeter across
the field terminal and the yoke or body. The meter should
read approximately 2 amps. If there is no reading the
field coil winding has a break in it. If the reading is much
more than 2 amps or the ohmmeter records at much less
than 8 ohms it shows that field coil insulation has broken
down. Renewal of the field coils is a specialist operation
best left to a service station.
The armature:
Apart from reconditioning the commutator, there is
little which can be done to the armature itself. Never try
to straighten a bent shaft and do not machine the arma-
ture core. Armature windings are tested w i t h equipment
normally not available to the car owner. The only check
for a suspected faulty armature which the owner can do
is to substitute an armature which is known to be
satisfactory.
Generator bearings:
1 Commutator end head bearings. Remove the ball-
bearing outer race stop bracket mounting screw and
nut, ease o u t t h e stop brackets and the ballbearings.
2 Fan end head bearing. Remove the ballbearing retainer
mounting screw nuts and ease o u t t h e retainers and
the seals. Using a suitably sized drift remove the ball-
bearing.
114Reassembly is the reverse procedure to dismantling
in both cases.
Reassembly and refitting the generator:
This is the reverse procedure to dismantling. The
following points should however be noted.
1 The commutator end head ballbearing outer race stop
bracket mounting screw nut must be tightened to a
torque wrench setting of .80 Ib ft.
2 The pulley and fan-to-generator armature shaft self-
locking nuts must be tightened to a torque wrench
setting of 14.5 Ib ft.
3 To assemble the commutator end bracket to the yoke,
partially withdraw the brushes and trap them in this
position by letting the springs bear on the sides of the
brushes. Fit the bracket to the armature shaft and when
it is about 1/2 inch from the yoke face, lift the springs
using a thin screwdriver or a piece of hooked wire and
this will let the brushes drop onto the commutator.
Check that the springs now bear correctly on the tops
of the brushes and push the bracket fully home.
4 Pack all ballbearings with Fiat Jota 3 grease or an
equivalent grade grease.
11:4 The starter motor
Operation:
When operating the starter hand lever through a
flexible coupling a lever is operated (see FIG 11:5)
which controls the pinion engagement with the flywheel.
As the lever completes its movement it closes the starter

Before removing an apparently faulty horn check the
wiring and connections. Check that the mounting bolts
are tight and that the horn does not foul any adjacent part.
Removal and installation:
This is a straightforward operation and the only
precaution to be taken is to ensure that the rubber gasket
bonded to the horn body does not become detached. If
the horn is renewed, before installing the new horn bond
the rubber gasket to the new unit with adhesive in
the same position as was on the original horn unit fitted.
Should the horn fail to operate the following points
should be noted.
1 Damaged horn.
2 Broken connection between battery and horn.
3 Broken connection between horn and push button on
steering wheel
4 Damaged push button mechanism.
5 Directional signal and outer lighting changeover
switch blade contact failing to make contact with the
steering wheel hub ring contact.
6 Current lead displaced from the horn blade contact on
the directional signal and outer lighting switch.
7 Distorted or broken diaphragm in horn.
8 Connections or inner windings
broken or burnt.
9 Electro-magnet contact points dirty or excessively
worn.The contacts may be adjusted by the adjusting screw
after the points have been cleaned and refaced.
To adjust the tone of the horn use a ring spanner and
screwdriver as shown in FIG 11 :23.
It is recommended that if the horn unit operation is
unreliable a new unit should be fitted rather than the
original one repaired.
11:12 Lighting and flasher switch
Description:
The two switches provide a directional signal switch
which automatically returns to the rest position once a
turn has been negotiated and the steering wheel is
brought back to the straight-ahead position. The change
over switch controls the outer lights and the headlights
flasher. The complete unit is located under the steering
wheel on the steering column.
Switch unit removal:
1 Carefully pry off the horn push button at the steering
wheel centre using a fine blade screwdriver.
2 Disconnect the positive terminal of the battery.
3 Disconnect the plug in contact in the steering wheel
hub.
4 Unscrew the steering wheel retaining nut from the
inner column and remove the steering wheel from the
shaft.
5 Slacken the bolts securing the steering column support
to the body
6 Remove the plug in contacts from the switch unit
ensuring that their correct location is noted for re-
assembly.7 Remove the switch unit from the steering column.
124
Switch unit installation:
This is the reverse procedure to dismantling. It is
advisable after installation to check that the steering
wheel when in the straight-ahead position and the
directional signal switch lever in neutral, the reference
index on the outer face of the directional signal switch
drum is in line with the index on the steering wheel hub.
This will ensure correct sequence of operation.
11:13 Fault diagnosis
(a) Battery discharged
1 Lighting circuit shorted
2 Terminals loose or dirty
3 Generator not charging
4 Regulator or cut-out units not working properly
5 Battery internally defective
(b) Insufficient charging current
1 Loose or corroded battery terminals
2 Generator driving belt slipping
(c) Battery will not hold a charge
1 Low electrolyte level
2 Battery plates sulphated
3 Electrolyte leakage from cracked casing or top sealing
compound
4 Plate separators ineffective
(d) Battery overcharged
1 Voltage regulator needs adjusting
(e) Generator output low or nil
1 Belt broken or slipping
2 Regulator unit out of adjustment
3 Worn bearings, loose pole pieces
4 Commutator worn, burned or shorted
5 Armature shaft bent or worn
6 Insulation proud between commutator segments
7 Brushes sticking, springs weak or broken
8 Field coil wires shorted, broken or burned
( f ) Starter motor lacks power or will not operate
1 Battery discharged, loose cable connections
2 Starter pinion jammed in mesh with flywheel gear
3 Starter switch faulty
4 Brushes worn or sticking, heads detached or shorting
5 Commutator dirty or worn
6 Starter shaft bent
7 Engine abnormally stiff
(g) Starter motor inoperative
1 Check 1 in (f)
2 Armature or field coils faulty