1983 FIAT UNO wheel bolts

0•8Roadside Repairs
To avoid repetition, the procedure for
raising the vehicle, in order to carry out work
under it, is not included before each relevant
operation described in this Manual.
It is to be preferred, and it is certainly
recommended, that the vehicle is positioned
over an inspection pit or raised on a lift. Where
these facilities are not available, use ramps or
jack up the vehicle strictly in accordance with
the following guide. Once the vehicle is raised,
supplement the jack with axle stands.
Jacking
The jack supplied with the car should only
be used to change a wheel. Do not use this
jack when overhaul or repair work is being
carried out; employ a hydraulic or screw jack
and supplement it with axle stands.
Jacking points are located under the sills
for use with the jack supplied.To raise the front end with a garage jack,
locate the jack under the transmission lower
mounting, just below and slightly to the rear of
the transmission oil drain plug. Protect the
mounting by placing a block of wood between
the jack head and the mounting.
To raise the rear of the car, the jack should
be placed under the spare wheel housing as
far to the rear as possible. Place a wooden
bearer between the jack head and the
housing.
Towing
When being towed, use the left-hand front
towing eye.
When towing another vehicle, use the rear
towing eye adjacent to the exhaust tailpipe.
When being towed, remember that the
brake pedal will require heavier pressure due
to lack of servo assistance. Always turn theignition key to MAR to retain the steering in
the unlocked position.
Wheel changing
With the car on firm level ground, apply the
handbrake fully. Remove the hub cap or
wheel trim, if fitted.
Release, but do not remove, the bolts.
Chock the front and rear of the opposite
roadwheel and then raise the car using the sill
jack supplied with the car if it is being done at
the roadside. Alternatively use a workshop
jack supplemented with axle stands.
Remove the wheel bolts, change the wheel
and screw in the bolts finger tight. It is
recommended that the bolt threads are
smeared with multi-purpose grease. Lower
the car, remove the jack and tighten the wheel
bolts to the specified torque. Refit any wheel
trim that was removed.
Spare wheel and jack stowage
Front tow hook Rear tow hook
Jacking, towing and wheel changing

Cylinder head and valves
Material (cylinder head) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Light alloy
Maximum distortion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.05 mm (0.002 in)
Valve guide bore in head . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.950 to 12.977 mm (0.5099 to 0.5109 in)
Valve guide outside diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.010 to 13.030 mm (0.5122 to 0.5130 in)
Valve guide oversizes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.5, 0.10, 0.25 mm (0.002, 0.004, 0.010 in)
Inside diameter of valve guide (reamed) . . . . . . . . . . . . . . . . . . . . . . . . . 7.022 to 7.040 mm (0.2765 to 0.2772 in)
Guide fit in head (interference) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.033 to 0.080 mm (0.0013 to 0.0032 in)
Valve stem diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.982 to 7.000 mm (0.2748 to 0.2756 in)
Maximum clearance (valve stem to guide) . . . . . . . . . . . . . . . . . . . . . . . 0.022 to 0.058 mm (0.0009 to 0.0023 in)
Valve seat angle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44º 55’ to 45º 05’
Valve face angle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45º 25’ to 45º 35’
Valve head diameter:
Inlet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29.0 mm (1.1417 in)
Exhaust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26.0 mm (1.0236 in)
Contact band (valve to seat) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.3 to 1.5 mm (0.0512 to 0.0591 in)
Valve clearance:
Inlet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.15 mm (0.006 in)
Exhaust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.20 mm (0.008 in)
For timing check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.60 mm (0.024 in)
Valve timing:
Inlet valve:
Opens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7º BTDC
Closes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36º ABDC
Exhaust valve:
Opens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38º BBDC
Closes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5º ATDC
Lubrication system
Oil pump type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gear, driven by shaft from camshaft
Tooth tip to body clearance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.05 to 0.14 mm (0.0020 to 0.0055 in)
Gear endfloat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.020 to 0.105 mm (0.0008 to 0.0041 in)
Oil pressure at normal operating temperature and average road/
engine speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.94 to 3.92 bar (42 to 57 lbf/ in
2)
Oil capacity (with filter change) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.42 litre (6.0 pint)
Oil type/specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Multigrade engine oil, viscosity SAE 15W/40
Oil filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Champion C101
Torque wrench settingsNm lbf ft
Cylinder head bolts:
Stage 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 22
Stage 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 43.5
Camshaft sprocket bolt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 36
Main bearing cap bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 51
Big-end bearing cap bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 30
Crankshaft pulley nut . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98 72
Flywheel bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 32
Rocker pedestal nuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 29
Engine mounting bracket bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 18
Engine mounting centre nuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 36
Exhaust manifold nuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 15
Spark plugs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 18
Temperature sender switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 36
Driveshaft to hub nuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272 200
Hub carrier to strut clamp bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 36
Roadwheel bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86 63
Brake caliper mounting bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 39
Tie-rod end balljoint nuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 25
Driveshaft inboard boot retainer bolts . . . . . . . . . . . . . . . . . . . . . . . . . . 9 7
Engine – general 1•3
1

Auxiliary shaft
Bearing internal diameter (reamed):
No. 1 (timing belt end) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35.664 to 35.684 mm (1.4052 to 1.4059 in)
No. 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32.000 to 32.020 mm (1.2608 to 1.2616 in)
Shaft journal diameter:
No. 1 (timing belt end) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35.593 to 35.618 mm (1.4024 to 1.4033 in)
No. 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31.940 to 31.960 mm (1.2584 to 1.2592 in)
Cylinder block and crankcase
Material . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Cast-iron
Bore diameter:
1116 cc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80.000 to 80.050 mm (3.152 to 3.154 in)
1301 cc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86.400 to 86.450 mm (3.404 to 3.406 in)
Maximum cylinder bore taper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.015 mm (0.0006 in)
Maximum cylinder bore ovality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.015 mm (0.0006 in)
Torque wrench settingsNm lbf ft
Cylinder head bolts:
Stage 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 15
Stage 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 30
Stage 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Turn through 90º Turn through 90º
Stage 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Turn through 90º Turn through 90º
Camshaft carrier to cylinder head . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 15
Main bearing cap bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 59
Big-end cap nuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 38
Flywheel mounting bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 61
Camshaft sprocket bolt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 61
Belt tensioner bolt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 32
Exhaust manifold nuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 21
Auxiliary shaft sprocket bolt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 61
Flexible mounting bracket bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 44
Flexible mounting centre nuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 36
Oil pressure switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 24
Spark plugs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 18
Roadwheel bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86 63
Driveshaft/hub nuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 272 200
Tie-rod end balljoint nuts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 25
Brake caliper mounting bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 39
Front strut lower clamp bolts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 36
Driveshaft inboard boot retainer bolts . . . . . . . . . . . . . . . . . . . . . . . . . . 9 7
Crankshaft pulley nut . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98 7
1•6 Engine – general
Part 1: General
1 Description
1The Uno may be powered by one of three
engines depending upon the particular model.
903 cc
2This is of four cylinder overhead valve type
with a light alloy cylinder head and a cast-iron
block and crankcase.
3A three bearing crankshaft is used and the
chain-driven camshaft runs in three steel
backed white metal bearings.
4The light alloy pistons are fitted with two
compression and one oil control ring. The
gudgeon pin is an interference fit in the small
end of the connecting rod.
5Lubrication is provided by an oil pump
within the sump pan and both the pump and
the distributor are driven from a gear on the
camshaft. Pressurised oil passes through acartridge type oil filter. An oil pressure relief
valve is incorporated in the oil pump. The
engine oil is independent of the transmission
lubricant.
1116 cc and 1301 cc
6These engines are of single overhead
camshaft type, the camshaft being driven by a
toothed belt.
7The difference in engine capacity is
achieved by increasing the cylinder bore on
the 1301 cc engine.
8The cylinder head is of light alloy while the
cylinder block and crankcase are of cast-iron
construction.
9A five bearing crankshaft is used and the
camshaft runs in a similar number of bearings,
but as these are in-line bored directly in the
camshaft carrier, no repair is possible.
10The pistons are of light alloy with two
compression and one oil control ring. The
gudgeon pin is an interference fit in the small
end of the connecting rod.
11An auxiliary shaft, driven by the timing belt
is used to drive the distributor, oil pump and
fuel pump.12The oil pump is located within the sump
pan and incorporates a pressure relief valve.
13Pressurised oil passes through a cartridge
type oil filter.
14The crankshaft main bearings are
supplied under pressure from drillings in the
crankcase from the main oil gallery whilst the
connecting rod big-end bearings are
lubricated from the main bearings by oil
forced through the crankshaft oilways. The
camshaft bearings are fed from a drilling from
the main oil gallery. The cams and tappets are
lubricated by oil mist from outlets in the
camshaft bearings.
15The cylinder walls, pistons and gudgeon
pins are lubricated by oil splashed up by the
crankshaft webs. An oil pressure warning light
is fitted to indicate when the pressure is too
low.
All engines
16The engine is mounted transversely with
the transmission at the front of the car.
17The engine oil is independent of the
transmission lubricant.

Cylinder head - removal and refitting
Sump pan - removal and refitting
Pistons/connecting rods - removal and
refitting
Oil pump - removal and refitting
Engine mountings - renewal
1116 cc and 1301 cc engines
Valve clearances - checking and adjusting
Camshaft and camshaft carrier - removal
and refitting
Timing belt - removal and refitting
Cylinder head - removal and refitting
Sump pan - removal and refitting
Oil pump - removal and refitting
Pistons/connecting rods - removal and
refitting
Engine mountings - renewal
Part 2:
903 cc engine
5 Valve clearances-
adjustment
2
1Adjust the valves when the engine is cold.
2Unbolt and remove the rocker cover.
3It is important that the clearance is set
when the cam follower of the valve being
adjusted is on the heel of the cam (ie;
opposite the peak). This can be done by
carrying out the adjustments in the following
order, which also avoids turning the
crankshaft more than necessary.
4Turn the crankshaft either using a spanner
on the pulley nut or by raising a front
roadwheel, engaging a gear (3rd or 4th) and
turning the wheel in the forward direction of
travel. It will be easier to turn the engine if the
spark plugs are first removed.
Valve fully open Check and adjust
Valve No. 8 EX Valve No. 1 EX
Valve No. 6 IN Valve No. 3 IN
Valve No. 4 EX Valve No. 5 EX
Valve No. 7 IN Valve No. 2 IN
Valve No. 1 EX Valve No. 8 EX
Valve No. 3 IN Valve No. 6 IN
Valve No. 5 EX Valve No. 4 EX
Valve No. 2 IN Valve No. 7 IN5Count the valves from the timing cover end
of the engine.
6Remember, the inlet and exhaust valve
clearances are different.
7Insert the appropriate feeler gauge between
the end of the valve stem and the rocker arm.
It should be a stiff sliding fit (photo).
8If the clearance is incorrect, release the
rocker arm adjuster screw locknut using a ring
spanner. Turn the adjuster screw using a
small open-ended spanner, but tie something
to it in case it is inadvertently dropped
through one of the pushrod holes.
9Once the clearance is correct, tighten the
locknut without moving the position of the
adjuster screw.
10Repeat the operations on the remaining
seven valves.
11Re-check all the clearances. Make sure
that the rocker cover gasket is in good
condition and fit the rocker cover.
6 Timing chain and sprockets
- removal and refitting
3
1Remove the alternator drivebelt as
described in Chapter 2.
2Unscrew and remove the crankshaft pulley
nut.3Disconnect the hoses from the fuel pump.
4Unbolt and remove the fuel pump with
spacer and rod.
5Support the engine on a hoist or under the
sump and disconnect and remove the
right-hand mounting. Then unscrew and
remove the timing cover bolts. The base of
the cover is secured by the front two sump
pan studs. Unbolt and lower the front end of
the sump. Avoid breaking the gasket. Remove
the timing cover.
6Undo and remove the camshaft sprocket
securing bolt; this will also release the fuel
pump drive cam from the end of the camshaft.
Note the timing marks on the camshaft and
crankshaft sprockets.
7Using two tyre levers, carefully ease the two
sprockets forwards away from the crankcase.
Lift away the two sprockets and timing chain.
8Remove the Woodruff key from the
crankshaft nose with a pair of pliers and note
how the channel in the pulley is designed to fit
over it. Place the Woodruff key in a container
as it is a very small part and can easily
become lost. The camshaft sprocket is
located on the camshaft by a dowel peg.Refitting
9Fit the Woodruff key to the front of the
crankshaft.
10Tap the crankshaft sprocket onto the front
of the crankshaft.
11Turn the sprocket so that the Woodruff
key is uppermost.
12Turn the camshaft until it is in such a
position that if the sprocket was fitted the
dimple timing mark on the sprocket would be
nearest to and in alignment with, the one on
the crankshaft sprocket.
903 cc engine 1•9
5.7 Adjusting a valve clearance
1 Sprocket retaining bolt
2 Fuel pump eccentric cam
3 Timing chain4 Camshaft sprocket
5 Sprocket locating dowel
6 Camshaft7 Woodruff key
8 Crankshaft
9 Crankshaft sprocket
Fig. 1.6 Timing chain and sprockets (Sec 6)
1
To prevent the crankshaft
rotating, either select a gear
and have an assistant apply
the footbrake hard or
remove the starter motor and lock the
ring gear teeth with a large cold chisel
or screwdriver.

Fig. 1.20 Flywheel housing cover plate
removed (Sec 13)
Fig. 1.19 Left-hand flexible
mounting (Sec 13)
10Disconnect the leads from the reversing
lamp switch.
11Disconnect the coolant hoses from the
cylinder head and coolant pump.
12Disconnect the fuel inlet hose from the
fuel pump. Plug the hose.
13Disconnect the throttle and choke
controls from the carburettor.
14Disconnect the heater hoses from the
engine.
15Disconnect the fuel return hose from the
carburettor.
16Disconnect the exhaust downpipe from
the manifold.
17Raise the front end of the car and support
it securely on axle stands. Remove the
roadwheels.
18Unscrew the driveshaft to hub nuts. These
are very tight and a long knuckle bar will be
required when unscrewing them. Have anassistant apply the brakes hard to prevent the
hub turning.
19Working under the car, remove the
protective shields and disconnect the exhaust
system mountings and withdraw it to the
rear.
20Disconnect the forward ends of the
gearchange rods by prising their sockets from
the ballstuds.
21Unscrew the nuts on the steering tie-rod
end balljoints and using a suitable “splitter”
tool separate the balljoints from the steering
arms. Unbolt the brake calipers and tie them
up out of the way.
22Unscrew and remove the bolts which
secure the hub carriers to the U-clamps at the
base of the suspension struts (photo).
23Pull the tops of the hub carriers from the
clamps and release the driveshafts from the
hub carriers.24Tie the driveshafts in a horizontal plane
with lengths of wire.
25Support the engine on a hoist or use a
trolley jack under the engine/transmission and
remove the bottom mounting and then the
upper left and right-hand ones (photo).
26Carefully lower the power unit to the floor
and withdraw it from under the car.
27External dirt and grease should now be
removed using paraffin and a stiff brush or a
water-soluble solvent.
28Unbolt and remove the engine mounting
brackets and the starter motor.
29Unbolt and remove the cover plate and
gearchange ball stud strut from the lower front
face of the flywheel housing.
30With the engine resting squarely on its
sump pan unscrew the flywheel housing
connecting bolts noting the location of any
lifting lugs and hose and wiring brackets.
1•14 903 cc engine
13.25 Right-hand engine mounting
Fig. 1.18 Hub carrier detached
from strut clamp (Sec 13)
13.22 Hub carrier strut clamp
Fig. 1.17 Tie-rod end balljoint
disconnected (Sec 13)Fig. 1.16 Gearchange rods
disconnected (Sec 13)
Fig. 1.15 Fuel return hose
disconnected from carburettor
(Sec 13)Fig. 1.14 Fuel inlet hose
disconnected from pump
(Sec 13)Fig. 1.13 Coolant hose at rear
of coolant pump (Sec 13)Fig. 1.12 Coolant hoses at
thermostat housing (Sec 13)

16 Engine-
complete dismantling
3
1Unbolt and remove the rocker cover.
2Unscrew the rocker pedestal securing nuts
and lift away the rocker assembly.
3Remove the pushrods, keeping them in
their original fitted order.
4Remove the cylinder head as described in
Section 7. Remove the dipstick and guide
tube.5Turn the engine on its side and unbolt and
remove the sump pan.
6Remove the piston/connecting rods as
described in Section 9.
7Unscrew and remove the crankshaft pulley
nut. To prevent the crankshaft rotating while
this is done, either jam the flywheel ring gear
or place a block between a crankshaft
counterweight and the inside of the
crankcase.
8Unbolt and remove the timing cover.
9Remove the timing chain and sprockets as
described in Section 6. 10Unbolt and remove the oil pump as
described in Section 10.
11Unscrew and remove the camshaft front
bearing lockscrew noting that the chamfer on
the bearing is on the inboard side.
12Withdraw the camshaft, taking great care
not to damage the bearings with the cam
lobes.
13Lift out the cam followers and keep them
in their originally fitted sequence.
14Unbolt and remove the flywheel. Jam the
ring gear teeth to prevent rotation.
15Remove the engine rear plate.
16Turn the cylinder block so that it is
standing upside down.
17Unbolt and remove the crankshaft rear oil
seal carrier. Note the sump fixing studs.
18The main bearing caps should be marked
1, 2 and 3 but if they are not, centre punch
them and note which way round they are
located.
19Unscrew the main bearing cap bolts
progressively.
20Remove the bearing caps and half shells.
If the shell bearings are to be used again,
keep them with their respective caps.
21Note the semi-circular thrust washers on
either side of the centre main bearing which
control crankshaft endfloat.
22Lift the crankshaft from the crankcase.
23Remove the bearing shells from the
crankcase and mark them as to position if
they are to be used again.
17 Cylinder head- dismantling
and decarbonising
4
1The exhaust manifold and rocker gear will
have been removed from the cylinder head
during removal (see Section 7).
2The valves should now be removed using a
universal valve spring compressor.
3Compress the first valve spring and extract
the split cotters.
4Gently release the compressor, take off the
spring retaining cap, the valve spring and the
spring seat. Remove the valve. Keep the valve
with its associated components together and
in numbered sequence so that they can be
returned to their original positions.
5A small box with divisions is useful for this
purpose. Remove and discard the valve stem
oil seals.
6Remove the other valves in a similar way.
7Bearing in mind that the cylinder head is of
1•16 903 cc engine
Fig. 1.23 Timing cover, sump pan and oil seals (Sec 16)
Fig. 1.24 Crankshaft and flywheel (Sec 16)
1 Sump pan bolt
2 Washer
3 Sealing strip
4 Side gasket
5 Side gasket
6 Block/crankcase
7 Gasket8 Bolt
9 Washer
10 Bolt and washer
11 Crankshaft front oil
seal
12 Timing cover
14 Gasket13 Fuel pump studs
and bush
15 Cover plate
16 Bolt and washer
17 Bolt
18 Bolt
19 Washer20 Crankshaft rear oil
seal
21 Oil seal carrier
22 Gasket
23 Sealing strip
24 Sump pan
25 Drain plug
1 Centre main
bearing shells
2 Front main bearing
shells3 Crankshaft
4 Plug
5 Starter ring gear6 Dowel
7 Flywheel
8 Thrust plate9 Bolt
10 Thrust washers
11 Rear main bearing
shells
If the valve spring refuses to
compress, do not apply
excessive force, but remove
the compressor and place a
piece of tubing on the spring retainer
and strike it a sharp blow to release the
collets from the valve stem. Refit the
compressor and resume operations
when the collets should come out.

clearance and end gap. Both clearances
should be checked with a feeler gauge. Check
the end gap when the ring has been pushed
squarely down the cylinder bore for two or
three inches (photos).
25If new rings are being used and the
cylinder bores have not been rebored, always
make sure that the top compression ring has
been stepped to prevent it contacting the
bore wear ridge.
Flywheel
26Check the clutch mating surface of the
flywheel. If it is deeply scored (due to failure to
renew a worn driven plate) then it may be
possible to have it surface ground provided
the thickness of the flywheel is not reduced
too much.
27If lots of tiny cracks are visible on the
surface of the flywheel then this will be due to
overheating caused by slipping the clutch or
“riding” the clutch pedal.
28With a pre-engaged type of starter motor
it is rare to find the teeth of the flywheel ring
gear damaged or worn but if they are, then the
ring gear will have to be renewed.
29To remove the ring gear, drill a hole
between the roots of two teeth taking care not
to damage the flywheel and then split the ring
with a sharp cold chisel.
30The new ring gear must be heated to
between 180 and 220ºC (356 and 428ºF)
which is very hot, so if you do not have
facilities for obtaining these temperatures,
leave the job to your dealer or engine
reconditioner.
31Where such facilities are available, then
the ring gear should be either pressed or
lightly tapped gently onto its register and left
to cool naturally, when the contraction of the
metal on cooling will ensure that it is a secure
and permanent fit. Great care must be taken
not to overheat the ring gear, as if this
happens its temper will be lost. A clutch input
shaft pilot bearing is not fitted on this engine.
Camshaft
32Examine the camshaft bearings for wear,
scoring or pitting. If evident then the bearings
will have to be renewed. The three bearingsare of different sizes and they can be removed
and new ones fitted using a bolt, nut and
distance pieces. When drawing a new bearing
into position, make sure that the oil hole is
correctly aligned with the one in the
crankcase. The centre and rear bearings
require reaming after fitting, the bearing at the
timing chain end is supplied ready reamed
(photo).
33The camshaft itself should show no marks
or scoring on the journal or cam lobe
surfaces. Where evident, renew the camshaft
or have it reprofiled by a specialist
reconditioner.
34Check the teeth of the camshaft sprocket
for wear. Renew the sprocket if necessary.
Cam followers
35Examine the bearing surface of the cam
followers which are in contact with the
camshaft. Any indentations or cracks must be
rectified by renewal. Clean sludge and dirt
from the cam followers and check their fit in
their bores. Side to side rock is unusual
except at very high mileage.
Timing chain
36Examine the teeth on both the crankshaft
sprocket and the camshaft sprocket for wear.
Each tooth forms an inverted “V” with the
sprocket periphery and if worn, the side of
each tooth under tension will be slightly
concave in shape when compared with the
other side of the tooth, ie; one side of the
inverted “V” will be concave when compared
with the other. If any sign of wear is present
the sprockets must be renewed.
37Examine the links of the chain for side
slackness and particularly check the
self-tensioning links for freedom of
movement. Renew the chain if any slackness
is noticeable when compared with a new
chain. It is a sensible precaution to renew the
chain at about 60 000 miles (96 000 km) and
at a lesser mileage if the engine is stripped
down for a major overhaul.
Cylinder head
38This is covered in Section 17.
Rockers and rocker shaft
39Thoroughly clean out the rocker shaft. As
it acts as the oil passages for the valve gear,
clean out the oil holes and make sure they are
quite clear. Check the shaft for straightness
by rolling it on a flat surface. If it is distorted,
renew it.
40The surface of the shaft should be free
from any wear ridges caused by the rocker
arms. If it is not, the shaft will have to be
renewed. Blocked shaft oil holes often
contribute to such wear.
41Check the rocker arms for wear of the
rocker bushes, for wear at the rocker arm face
which bears on the valve stem, and for wear
of the adjusting ball ended screws. Wear in
the rocker arm bush can be checked by
gripping the rocker arm tip and holding the
rocker arm in place on the shaft, noting if
there is any lateral rocker arm shake. If any
shake is present, and the arm is very loose on
the shaft, remedial action must be taken. It is
recommended that a worn rocker arm be
taken to your local FIAT agent or automobile
engineering works to have the old bush drawn
out and a new bush fitted (photo).
42Check the tip of the rocker arm where it
bears on the valve head, for cracking or
serious wear on the case hardening. If none is
present the rocker arm may be refitted. Check
the pushrods for straightness by rolling them
on a flat surface.
Oil pump
43Unscrew the four securing bolts which
connect the two halves of the pump body.
44Clean all the components in a bath of
paraffin and dry them.
45Inspect the gears for wear or damage and
then check for wear in the following way.
46Insert a feeler blade between the tooth
peak and the body. This should be between
0.05 and 0.14 mm (0.0019 and 0.0055 in).
47Now place a straight-edge across the
body flange and check for gear endfloat. This
should be between 0.020 and 0.105 mm
(0.0008 and 0.0041 in). Where the clearances
exceed the specified limits, renew the pump.
48Check that the oil pressure relief valve
spring is in good condition and not deformed.
903 cc engine 1•19
18.41 Rocker components18.32 Camshaft bearing18.24B Checking piston ring end gap
1

micrometer to trace the cause of the trouble.
It is very seldom that any trouble of this nature
will be experienced when fitting the
crankshaft.
9Tighten the main bearing bolts to the
specified torque wrench settings (photo).
10Using a dial gauge or feeler blades
inserted between a thrust washer and the
crankshaft, check the crankshaft endfloat. If it
exceeds the specified limit, the thrust washers
can be changed for thicker ones (photo).
11Bolt on the crankshaft rear oil seal carrier
using a new gasket. The carrier should have
been fitted with a new oil seal and the seal lips
greased (photos).
12Fit the engine rear plate (photo).
Flywheel
13Offer the flywheel to the crankshaft. With
pistons No. 1 and 4 at TDC, the dimple on the
flywheel must be uppermost.
14Screw in and tighten the bolts to the
specified torque. The crankshaft may be held
against rotation by either jamming the starter
ring gear or placing a block of wood between
one of the crankshaft webs and the inside of
the crankcase (photo).
Camshaft
15Oil the cam followers and return them to
their original positions (photo).
16Oil the camshaft bearings and insert the
camshaft, taking great care not to damage the
bearings with the cam lobes. Fit the front
bearing, chamfer inwards (photos).
903 cc engine 1•21
20.10 Checking crankshaft end float20.9 Tightening main bearing cap bolts20.6 Fitting a main bearing cap
20.16B Camshaft front bearing20.16A Fitting camshaft
20.11B Crankshaft oil seal and carrier
fitted20.11A Crankshaft rear oil seal carrier and
gasket
20.14 Tightening flywheel bolts20.12 Engine rear plate
20.15 Cam followers
1