1983 FIAT UNO check engine

13Engage the timing chain with the teeth of
the crankshaft sprocket. Then locate the
camshaft sprocket within the upper loop of
the chain in such a way that when the
sprocket is pushed onto the camshaft, the
timing marks will be in alignment. Make sure
that the self-tensioning links are on the inside
of the chain against the cylinder block
(photos).
14Place the camshaft sprocket onto the
camshaft so that its positioning dowel
engages.
15Secure the camshaft sprocket by fitting
the special cam, that drives the fuel pump, on
its locating dowel. Fit the camshaft sprocket
retaining bolt (photo).
16Tighten the sprocket bolt to the specified
torque.
17If the timing cover oil seal showed signs of
leaking before engine overhaul the old seal
should be removed and a new one fitted.
18Using a screwdriver, carefully remove the
old oil seal, working from the rear of the cover.
Fit the new seal making sure it is inserted
squarely, and tap home with a hammer.
19Lubricate the oil seal with engine oil.
20With all traces of old gasket and jointing
compound removed from the timing cover
and cylinder block mating faces, smear a little
grease onto the timing cover mating face and
fit a new gasket in position.
21Fit the timing cover to the cylinder block
and finger tighten the securing bolts, and
spring washer. Ensure that the fuel pump
pushrod bush is in place in the cover.22Wipe the hub of the pulley and carefully
place into position on the crankshaft. It should
locate on the Woodruff key. It may be
necessary to adjust the position of the timing
cover slightly in order to centralise the oil seal
relative to the pulley hub.
23Tighten the timing cover securing bolts in
a diagonal and progressive manner.
24Tighten the crankshaft pulley nut to the
specified torque again holding the crankshaft
against rotation as previously described
(paragraph 2) this Section.
25Refit the fuel pump and alternator
drivebelt.
7 Cylinder head-
removal and refitting
3
1For safety reasons, disconnect the battery
negative lead.
2Refer to Chapter 2 and drain the cooling
system.
3Refer to Chapter 3 and remove the
carburettor, air cleaner and spacer block.
4Undo and remove the five nuts and
washers securing the exhaust manifold and
hot air ducting to the cylinder head.
5Detach the cable from the temperature
indicator sender unit.
6Refer to Chapter 4 and disconnect the
distributor LT lead and the coil HT lead.
7Refer to Chapter 2 and remove the
thermostat housing from the cylinder head.
8Disconnect the coolant hoses from the
cylinder head.
9Note the electrical connections to the rear
of the alternator and disconnect them.
10Disconnect the mounting and adjuster link
bolts and remove the alternator from the
engine.
11Unscrew the four nuts securing the rocker
cover to the top of the cylinder head and lift
away the spring washers and metal packing
pieces. Remove the rocker cover and cork
gasket.
12Unscrew the four rocker pedestal
securing nuts in a progressive manner. Lift
away the four nuts and spring washers andease the valve rocker assembly from the
cylinder head studs.
13Remove the pushrods, keeping them in
the relative order in which they were removed.
The easiest way to do this is to push them
through a sheet of thick paper or thin card in
the correct sequence.
14Unscrew the cylinder head securing bolts
half a turn at a time in the reverse order to that
shown in Fig. 1.7; don’t forget the one within
the inlet manifold. When all the bolts are no
longer under tension they may be unscrewed
from the cylinder head one at a time. This will
also release a section of the cooling system
pipe secured by two of the bolts. All the bolts
have washers.
15The cylinder head may now be lifted off. If
the head is jammed, try to rock it to break the
seal. Under no circumstances try to prise it
apart from the cylinder block with a
screwdriver or cold chisel as damage may be
done to the faces of the head or block. If this
or the Hint, fail to work, strike the head
sharply with a plastic headed hammer, or with
a wooden hammer, or with a metal hammer
with an interposed piece of wood to cushion
the blows. Under no circumstances hit the
head directly with a metal hammer as this may
cause the casting to fracture. Several sharp
taps with the hammer, at the same time
pulling upwards, should free the head. Lift the
head off and place on one side.
16The cylinder head may now be de-
carbonised or dismantled, refer to Section 17.
Refitting
17After checking that both the cylinder block
and cylinder head mating surfaces are
perfectly clean, generously lubricate each
cylinder with engine oil.
18Always use a new cylinder head gasket as
the old gasket will be compressed and not
capable of giving a good seal.
1•10 903 cc engine
6.15 Fitting fuel pump drive cam and
sprocket bolt
6.13C Self-tensioning links on inside of
chain6.13B Timing mark alignment6.13A Fitting the sprockets and timing
chain
If the head will not readily
free, turn the crankshaft.
The compression generated
in the cylinders will often
break the gasket joint

9 Pistons/connecting rods-
removal and refitting
3
1Remove the cylinder head as described in
Section 7.
2Remove the sump pan as described in
Section 8.
3Undo and remove the big-end cap retaining
bolts and keep them in their respective order
for correct refitting.
4Check that the connecting rod and big-end
bearing cap assemblies are correctly marked.
Normally the numbers 1-4 are stamped on
adjacent sides of the big-end caps and
connecting rods, indicating which cap fits on
which rod and which way round the cap fits.
The numbers are located on the sides of the
rod and cap furthest away from the camshaft.
5If numbers are not evident, then use a sharp
file to make mating marks across the rod/cap
joint. One line for connecting rod No. 1, two
for connecting rod No. 2 and so on. This will
ensure that there is no confusion later as it is
most important that the caps go back in the
correct position on the connecting rods from
which they were removed. No. 1 piston should
be at the crankshaft pulley end of the engine.
6If the big-end caps are difficult to remove
they may be gently tapped with a soft-faced
hammer.
7To remove the shell bearings, press the
bearing opposite the groove in both the
connecting rod and the connecting rod caps
and the bearings will slide out easily.
8Keep the shells with their original cap or rod
if the bearings are not being renewed.
9Withdraw the pistons and connecting rods
upwards and ensure that they are kept in the
correct order for replacement in the same
bore.
10If the cylinder has a wear ridge at its upper
end then this may make it difficult to remove
the piston. In this event, relieve the sharp
edge of the ridge by scraping.
11Dismantling the pistons is described in
Section 18, paragraph 17.
12Lay the piston and connecting rod
assemblies in the correct order ready for
refitting into their respective bores.13With a wad of clean non-fluffy rag wipe
the cylinder bores clean.
14Position the piston rings so that their gaps
are 120º apart and then lubricate the rings.
15Wipe clean the connecting rod half of the
big-end bearing and the underside of the shell
bearing. Fit the shell bearing in position with
its locating tongue engaged with the
corresponding groove in the connecting rod.
16Fit a piston ring compressor to the top of
the piston, making sure it is tight enough to
compress the piston rings.
17Using a piece of fine wire double check
that the little jet hole in the connecting rod is
clean.
18The pistons, complete with connecting
rods, are fitted to their bores from above. The
number stamped on the connecting rod must
face away from the camshaft with the arrow
on the piston crown pointing towards the
timing cover.19With the base of the piston ring compressor
resting on the cylinder block, apply the wooden
handle of a hammer to the piston crown, strike
the hammer head with the hand and drive the
piston/rod into its bore (photo).
20Draw the rod, complete with shell bearing
down onto its crankpin.
21Generously lubricate the crankpin journals
with engine oil, and turn the crankshaft so that
the crankpin is in the most advantageous
position for the connecting rod to be drawn
into it.
22Wipe clean the connecting rod bearing
cap and back of the shell bearing and fit the
shell bearing in position ensuring that the
locating tongue at the back of the bearing
engages with the locating groove in the
connecting rod cap.
23Generously lubricate the shell bearing and
offer up the connecting rod bearing cap to the
connecting rod (photo).
1•12 903 cc engine
9.23 Big-end cap9.19 Fitting a piston/connecting rod
Fig. 1.8 Piston/connecting rod components (Sec 9)
1 Bolt
2 Connecting rod
3 Oil control ring4 Compression ring
(stepped at base)
5 Compression ring
(marked TOP)6 Gudgeon pin
7 Piston gudgeon pins
8 Big-end shell bearings
8.7B Sump pan nut, bolts and washers

light alloy construction and is easily damaged
use a blunt scraper or rotary wire brush to
clean all traces of carbon deposits from the
combustion spaces and the ports. The valve
head stems and valve guides should also be
freed from any carbon deposits. Wash the
combustion spaces and ports down with
paraffin and scrape the cylinder head surface
free of any foreign matter with the side of a
steel rule, or a similar article.
8If the engine is installed in the car, clean the
pistons and the top of the cylinder bores. If
the pistons are still in the block, then it is
essential that great care is taken to ensure
that no carbon gets into the cylinder bores as
this could scratch the cylinder walls or cause
damage to the piston and rings. To ensure
this does not happen, first turn the crankshaft
so that two of the pistons are at the top of
their bores. Stuff rag into the other two bores
or seal them off with paper and masking tape.
The waterways should also be covered with
small pieces of masking tape to prevent
particles of carbon entering the cooling
system and damaging the coolant pump.
9With a blunt scraper carefully scrape away
the carbon from the piston crown, taking care
not to scratch the aluminium. Also scrape
away the carbon from the surrounding lip of
the cylinder wall. When all carbon has been
removed, scrape away the grease which will
now be contaminated with carbon particles,
taking care not to press any into the bores. To
assist prevention of carbon build-up the
piston crown can be polished with a metal
polish. Remove the rags or masking tape from
the other two cylinders and turn the
crankshaft so that the two pistons which were
at the bottom are now at the top. Place rag in
the cylinders which have been decarbonised,
and proceed as just described.
10Examine the head of the valves for pitting
and burning, especially the heads of the
exhaust valves. The valve seatings should be
examined at the same time. If the pitting on
the valve and seat is very slight, the markscan be removed by grinding the seats and
valves together with coarse, and then fine,
valve grinding paste.
11Where bad pitting has occurred to the
valve seats it will be necessary to recut them
and fit new valves. This latter job should be
entrusted to the local agent or engineering
works. In practice it is very seldom that the
seats are so badly worn. Normally it is the
valve that is too badly worn for refitting, and
the owner can easily purchase a new set of
valves and match them to the seats by valve
grinding.
12Valve grinding is carried out as follows.
Smear a trace of coarse carborundum paste
on the seat face and apply a suction grinder
tool to the valve head. With a semi-rotary
motion, grind the valve head to its seat, lifting
the valve occasionally to redistribute the
grinding paste. When a dull matt even surface
is produced on both the valve seat and the
valve, wipe off the paste and repeat the
process with fine carborundum paste, lifting
and turning the valve to redistribute the paste
as before. A light spring placed under the
valve head will greatly ease this operation.
When a smooth unbroken ring of light grey
matt finish is produced, on both valve and
valve seat faces, the grinding operation is
complete. Carefully clean away every trace of
grinding compound, take great care to leave
none in the ports or in the valve guides. Clean
the valve seats with a paraffin soaked rag,
then with a clean rag, and finally, if an air line
is available, blow the valves, valve guides and
valve ports clean.
13Check that all valve springs are intact. If
any one is broken, all should be renewed.
Check the free height of the springs against
new ones. If some springs are not within
specifications, replace them all. Springs suffer
from fatigue and it is a good idea to renew
them even if they look serviceable.
14Check that the oil supply holes in the
rocker arms are clear.
15The cylinder head can be checked for
warping either by placing it on a piece of plate
glass or using a straight-edge and feeler
blades. If there is any doubt or if its block face
is corroded, have it re-faced by your dealer or
motor engineering works.
16Test the valves in their guides for side toside rock. If this is any more than almost
imperceptible, new guides must be fitted.
Again this is a job for your dealer as a special
tool is required to ensure the correct
installation depth and the cylinder head must
be warmed to 80ºC (176ºF) before fitting the
guides.
17Commence reassembly by oiling the stem
of the first valve and pushing it into its guide
which should have been fitted with a new oil
seal (photos).
18Fit the spring seat. Fit the valve spring so
that the closer coils are towards the cylinder
head and then fit the spring retaining cap.
19Compress the valve spring and locate the
split cotters in the valve stem cut-out (photo).
20Gently release the compressor, checking
to see that the collets are not displaced.
21Fit the remaining valves in the same way.
22Tap the end of each valve stem with a
plastic or copper-faced hammer to settle the
components.
23The cylinder head is now ready for
refitting as described in Section 7.
18 Examination and renovation
4
1With the engine stripped down and all parts
thoroughly clean, it is now time to examine
everything for wear. The following items
should be checked and where necessary
renewed or renovated as described in the
following Sections.
Cylinder block and crankcase
2Examine the casting carefully for cracks
especially around the bolt holes and between
cylinders.
3The cylinder bores must be checked for
taper, ovality, scoring and scratching. Start by
examining the top of the cylinder bores. If they
are at all worn, a ridge will be felt on the thrust
side. This ridge marks the limit of piston ring
travel. The owner will have a good indication
of bore wear prior to dismantling by the
quantity of oil consumed and the emission of
blue smoke from the exhaust especially when
the engine is cold.
4An internal micrometer or dial gauge can be
903 cc engine 1•17
17.19 Fitting split collets17.17B Inserting a valve into its guide17.17A Valve stem oil seal
1
Press a little grease into the
gap between the cylinder
walls and the two pistons
which are to be worked on.

used to check bore wear and taper against
the Specifications, but this is a pointless
operation if the engine is obviously in need of
reboring due to excessive oil consumption.
5Your engine reconditioner will be able to
re-bore the block for you and supply the
correct oversize pistons to give the correct
running clearance.
6If the engine has reached the limit for
reboring then cylinder liners can be fitted, but
here again this is a job for your engine
reconditioner.
7To rectify minor bore wear it is possible to
fit proprietary oil control rings. A good way to
test the condition of the engine is to have it at
normal operating temperature with the spark
plugs removed. Screw a compression gauge
(available from most motor accessory stores)
into the first plug hole. Hold the accelerator
fully depressed and crank the engine on the
starter motor for several revolutions. Record
the reading. Zero the tester and check the
remaining cylinders in the same way. All four
compression figures should be approximately
equal and within the tolerance given in the
Specifications. If they are all low, suspect
piston ring or cylinder bore wear. If only one
reading is down, suspect a valve not seating.
Crankshaft and bearings
8Examine the crankpin and main journal
surfaces for signs of scoring or scratches.
Check the ovality of the crankpins at different
positions with a micrometer. If more than
0.001 inch (0.025 mm) out of round, the
crankpins will have to be reground. They will
also have to be reground if there are any
scores or scratches present. Also check the
journals in the same fashion.
9Wear in a crankshaft can be detected while
the engine is running. Big-end bearing and
crankpin wear is indicated by distinct metallic
knocking, particularly noticeable when the
engine is pulling from low engine speeds. Low
oil pressure will also occur.
10Main bearing and journal wear is indicated
by engine rumble increasing in severity as the
engine speed increases. Low oil pressure will
again be an associated condition.
11Crankshaft grinding should be carried outby specialist engine reconditioners who will
supply the matching undersize bearing shells
to give the required running clearance.
12Inspect the connecting rod big-end and
main bearing shells for signs of general wear,
scoring, pitting and scratching. The bearings
should be matt grey in colour.
13If a copper colour is evident, then the
bearings are badly worn and the surface
material has worn away to expose the underlay.
Renew the bearings as a complete set.
14At the time of major overhaul it is
worthwhile renewing the bearing shells as a
matter of routine even if they appear to be in
reasonably good condition.
15Bearing shells can be identified by the
marking on the back of the shell. Standard
sized shells are usually marked STD or 0.00.
Undersized shells are marked with the
undersize such as 0.25 mm.
Connecting rods
16Check the alignment of the connecting
rods visually. If you suspect distortion, have
them checked by your dealer or engine
reconditioner on the special jig which he will
have.
17The gudgeon pin is an interference fit in
the connecting rod small-end and removal or
refitting and changing a piston is a job best
left to your dealer or engine reconditioner due
to the need for a press and jig and careful
heating of the connecting rod.
Pistons and piston rings
18If the cylinders have been rebored, then
the reconditioner will supply the oversize
pistons and rings and the gudgeon pins. Give
the job of fitting the new pistons to the
connecting rods to him.
19If the original piston rings or just new rings
are to be fitted to the original pistons, use
great care to remove and fit the rings as they
are easily broken if expanded too much.
Always remove and fit rings from the crown
end.
20If three old feeler blades are slid behind
the piston rings and located at equidistant
points, the rings may be removed or fitted
without their dropping into the wrong grooves
and will reduce the chance of breakage
(photo).
21If the original pistons are being refitted,
make sure that the ring grooves and their oil
return holes are cleaned out and freed from
carbon. A piece of piston ring is a useful tool
for this purpose.
22The three pistons rings are as follows:
Top - Thinner compression marked TOP
Second - Thicker compression, step at base
Bottom - Oil control (photo)
23If proprietary wear control rings are to be
fitted to overcome bore wear, fit them strictly
in accordance with the manufacturer’s
instructions.
24Always check the piston ring groove
1•18 903 cc engine
18.24A Checking piston ring groove
clearance18.22 Piston ring marking
18.20 Using feeler blades to fit piston ringsFig. 1.26 Piston/connecting rod
relationship (Sec 18)Fig. 1.25 Checking a crankpin (Sec 18)

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

removed and the weight of the car is again on
its roadwheels.
4Fill the cooling system.
5Fill the engine with oil.
6Replenish lost transmission oil.
7Reconnect the battery.
8Adjust the clutch pedal as described in
Chapter 5.
24 Engine- initial start-up after
overhaul or major repair
4
1Make sure that the battery is fully charged
and that all lubricants, coolant and fuel are
replenished.
2If the fuel system has been dismantled it will
require several revolutions of the engine on
the starter motor to pump the petrol up to the
carburettor.
3Turn the carburettor throttle speed screwthrough one complete turn to increase the idle
speed in order to offset the initial stiffness of
new engine internal components.
4As soon as the engine fires and runs, keep
it going at a fast idle speed and bring it up to
normal working temperature.
5As the engine warms up there will be odd
smells and some smoke from parts getting
hot and burning off oil deposits. The signs to
look for are leaks of water or oil which will be
obvious.
6Check also the exhaust pipe and manifold
connections as these do not always “find”
their exact gas tight position until the warmth
and vibration have acted on them and it is
almost certain that they will need tightening
further. This should be done, of course, with
the engine stopped.
7When normal running temperature has
been reached, adjust the engine idle speed as
described in Chapter 3.
8Stop the engine and wait a few minutes tosee if any lubricant or coolant is dripping out
when the engine is stationary.
9Road test the car to check that the timing is
correct and that the engine is giving the
necessary smoothness and power. Do not
race the engine - if new bearings and/or
pistons have been fitted it should be treated
as a new engine and run in at a reduced
speed for the first 500 km (300 miles).
10After the first 1500 km (900 miles) the
cylinder head bolts must be re-torqued in the
following way (engine cold).
11Remove the air cleaner and rocker cover.
Unscrew the first bolt (Fig. 1.7) through a
quarter turn and then tighten it to final stage 2
torque (see Specifications).
12Repeat on the remaining bolts, one at a
time.
13Check and adjust the valve clearances
(Section 5).
14Refit the rocker cover and air cleaner.
903 cc engine 1•23
26.4 Shim engraved mark26.2 Removing a shim from a cam follower25.4 Checking a valve clearance
1
Part 3: 1116 cc and 1301 cc engines
25 Valve clearances- checking
2
This should only be required if the valves
have been renewed or ground in, or at high
mileages when noise or poor engine
performance indicates that a check is
necessary.
It is important that each valve clearance is
set correct otherwise the timing will be
wrong and engine performance poor. If there
is no clearance at all, the valve and its seat
will soon burn. Always set the clearances
with the engine cold.
1Remove the camshaft cover. Jack-up a
front wheel and engage top gear so that by
turning the wheel, the crankshaft can be
rotated.
2Each valve clearance must be checked
when the high point of the cam is pointing
directly upward away from the cam follower.
3Check the clearances in the firing order
1-3-4-2, No. 1 cylinder being at the timing
belt end of the engine. This will minimise the
amount of crankshaft rotation required.4Insert the appropriate feeler blade
between the heel of the cam and the cam
follower shim of the first valve. If necessary
alter the thickness of the feeler blade until it
is a stiff, sliding fit. Record the thickness,
which will, of course, represent the valve
clearance for this particular valve (photo).
5Turn the crankshaft, check the second
valve clearance and record it.
6Repeat the operations on all the remaining
valves, recording their respective clearances.
7Remember that the clearance for inlet and
exhaust valves differs - see Specifications.
Counting from the timing cover end of the
engine, the valve sequence is:
Inlet 2-3-6-7
Exhaust 1-4-5-8
26 Valve clearances-
adjustment
3
1Check the valve clearances (Section 25).
2Clearances which are incorrect will mean
the particular shim will have to be changed.
To remove the shim, turn the crankshaft untilthe high point of the cam is pointing directly
upward. The cam follower will now have to
be depressed so that the shim can be
extracted. Special tools (A60642 and
A87001) are available from your Fiat dealer to
do the job, otherwise you will have to make
up a forked lever to locate on the rim of the
cam follower. This must allow room for the
shim to be prised out by means of the
cut-outs provided in the cam follower rim
(photo).
3Once the shim is extracted, establish its
thickness and change it for a thicker or
thinner one to bring the previously recorded
clearance within specification. For example,
if the measured valve clearance was 1.27
mm (0.05 in) too great, a shim thicker by this
amount will be required. Conversely, if the
clearance was 1.27 mm (0.05 in) too small, a
shim thinner by this amount will be required.
4Shims have their thickness (mm) engraved
on them; although the engraved side should
be fitted so as not to be visible, wear still
occurs and often obliterates the number. In
this case, measuring their thickness with a
metric micrometer is the only method to
establish their thickness (photo).

5In practice, if several shims have to be
changed, they can often be interchanged, so
avoiding the necessity of having to buy more
new shims than is necessary.
6If more than two or three valve clearances
are found to be incorrect, it will be more
convenient to remove the camshaft carrier for
easier removal of the shims.
7Where no clearance can be measured, even
with the thinnest available shim in position,
the valve will have to be removed and the end
of its stem ground off squarely. This will
reduce its overall length by the minimum
amount to provide a clearance. This job
should be entrusted to your dealer as it is
important to keep the end of the valve stem
square.
8On completion, refit the camshaft cover and
gasket.
27 Camshaft and camshaft
carrier- removal and refitting
3
1Disconnect the battery.
2Remove the air cleaner (see Chapter 3).
3Disconnect the fuel filter hose from the fuel
pump and tie it back, out of the way.
4Identify and then disconnect any electrical
leads which must be moved away to enable
the camshaft cover to be withdrawn.
5Identify and disconnect any vacuum gases
which must be moved away to enable the
camshaft cover to be withdrawn.
6Unscrew the securing nuts and remove the
camshaft cover.
7Turn the crankshaft pulley nut until No. 4
piston is at TDC. This can be established as
described in Section 28.
8Unbolt and remove the timing belt cover.
9Check that the timing mark on the camshaft
sprocket is aligned with, and adjacent to the
pointer on the timing belt cover backplate.
10Restrain the timing belt with the hand and
release but do not remove the camshaft
sprocket bolt. Release the belt tensioner
pulley by slackening the pulley centre nut.
Push the timing belt evenly from the
sprockets, noting which way round the belt isfitted if it is to be completely removed. The
lettering on the belt is normally legible from
the crankshaft pulley end of the engine when
the belt is as originally fitted.
11Unbolt the camshaft carrier and lift it
sufficiently from the cylinder head to break the
seal of the mating faces. Note: It is important
not to allow the cam followers to pull out; they
must be retained in their original locations.
This can be done if the carrier is raised very
slowly, until the fingers can be inserted to
prise the cam followers onto their respective
valve spring retainers. It is unlikely that the
valve clearance adjusting shims will be
displaced from their recesses in the cam
followers because of the suction of the
lubricating oil, but watch that this does not
happen; the shims must also be retained in
their originally fitted sequence.
12Remove the previously loosened
camshaft sprocket bolt and take the sprocket
from the camshaft.
13Unbolt and remove the camshaft end
cover with its gasket. Withdraw the camshaft
(photos).
14Refitting is a reversal of the removal
process, but observe the following points.
15Use new gaskets.
16Retain the cam followers and shims in
their bores in the camshaft carrier with thick
grease; they must not be allowed to drop out
when the carrier is lowered onto the cylinder
head.
17If the crankshaft or camshaft have been
moved from their set positions, re-align the
sprocket timing mark with the pointer on the
belt cover and the crankshaft pulley or
flywheel with the TDC mark. This must be
observed otherwise the valves may impinge
upon the piston crowns when the camshaft
lobes compress any of the valve springs
during bolting down of the carrier.
18Screw in the carrier bolts and tighten
them to the specified torque (photo).
19Refit and tension the timing belt as
described in Section 28.
20Refit the camshaft cover and gasket.
21Refit the hose and air cleaner.
22Reconnect the battery.
28 Timing belt- renewal
3
1Set No. 4 piston at TDC. Do this by turning
the crankshaft pulley nut or by jacking up a
front roadwheel, engaging a gear and turning
the wheel until the mark on the flywheel is
opposite to the TDC mark on the flywheel
bellhousing aperture. Remove No. 4 spark
plug, place a finger over the plug hole and feel
the compression being generated as the
crankshaft is rotated and the piston rises up
the cylinder bore.
2On some models the TDC marks on the
crankshaft pulley and belt cover may be
visible and can be used instead.
3Remove the alternator drivebelt (Chapter 2,
Section 8). Unbolt and remove the timing belt
cover.
4Check that the timing mark on the camshaft
sprocket is aligned with the pointer on the belt
cover backing plate (photo).
5Slacken the nut in the centre of the
tensioner pulley and push in on the support to
release the tension on the belt, then retighten
the nut. Slide the drivebelt off the pulleys.
6Check that the crankshaft and camshaft
pulleys have not been moved from their
previously aligned positions.
7To check that the auxiliary shaft sprocket
has not moved, take off the distributor cap
and check that the contact end of the rotor
arm is aligned with No. 4 HT lead contact in
the cap.
1•24 1116 cc and 1301 cc engine
28.4 Camshaft sprocket alignment marks
27.18 Tightening a camshaft carrier bolt27.13B Withdrawing camshaft from carrier27.13A Removing camshaft end cover