FIAT UNO 1983 Service Repair Manual

99Tighten the big-end bolts to the specified
torque (photo). The correct torque is
important as the bolts have no locking
arrangement. After tightening each big-end,
check that the crankshaft rotates smoothly.
100Repeat the operations on the remaining
piston/rod assemblies.
101Refit the oil pump pick-up assembly
using a new sealing ring.
102Refit the sump pan and the cylinder head
as described in earlier sub-Sections.
103Fill the engine with oil and coolant.
Pistons/connecting rods -
separation and piston
ring renewal
ª
104If the piston/connecting rods have been
removed in order to renew the piston rings,
refer to Chapter 1, Section 18, but note thatthe piston rings should be fitted so that the
word TOP is uppermost.
105If new pistons are to be fitted, it is
recommended that the gudgeon pins are
removed and refitted by a FIAT dealer as the
connecting rods must be carefully heated in
order to be able to push the gudgeon pin out
of the rod small-end, change the piston and
push the pin back into position. Locating the
gudgeon pin will require a special tool. The
gudgeon pin is a sliding fit in the piston but an
interference fit in the connecting rod.
106Refer to Fig. 13.6 for the correct
assembly of the piston and connecting rod.
Engine/transmission mountings
- renewal
107Refer to Chapter 1, Section 33. Three
mountings are used (photos).
PART C: ENGINE REMOVAL
AND DISMANTLING
Method of removal - general
1The engine, complete with transmission,
should be removed upwards out of the engine
compartment.
Engine/transmission -
removal and separation #
Warning: Refer to the beginning
of Section 9 before starting any
work.
2Mark the position of the hinges on the
underside of the bonnet and then, with the
help of an assistant, unscrew the hinge bolts
and lift the bonnet to a safe storage area.
3Drain the coolant; a cylinder block drain
plug is not fitted.
4Drain the engine and transmission oils.
5Disconnect the battery, negative lead first.
6Remove the air filter.
7Disconnect the radiator hoses from the
engine (photos).
13•26 Supplement: Revisions and information on later models
5C.7B Radiator hose at thermostat
housing5C.7A Radiator hose connection to coolant
distribution tube5B.107C Right-hand engine mounting
5B.107B Left-hand rear
engine/transmission mounting5B.107A Left-hand front
engine/transmission mounting
Fig. 13.6 Piston/connecting rod correctly
assembled - 999 and 1108 cc engine
(Sec 5B)
1 Piston grade (A) and directional arrow on
piston crown (towards timing belt)
2 Rod/cap matching numbers
3 Gudgeon pin offset in piston (0.9 to 1.1 mm)
Arrow indicates crankshaft rotation direction
Fig. 13.5 Piston ring arrangement on the
999 cc engine (Sec 5B)5B.99 Tightening a big-end cap bolt

8Disconnect the heater hose from the inlet
manifold.
9On fuel injection models, depressurize the
fuel system (refer to Section 9D). Disconnect
the fuel inlet and return hoses from the fuel
pump (photo) or throttle body, as applicable.
10Disconnect the brake servo vacuum hose
from the inlet manifold.
11Disconnect the throttle cable from the
carburettor, or throttle body as applicable.
12Disconnect the choke cable, if applicable
(photo).
13Disconnect the leads from the alternator.
14Disconnect the battery earth lead from the
transmission casing.15Disconnect the leads from the starter
motor and the HT lead from the ignition coil
(photo).
16Disconnect the coolant temperature
switch lead and the HT leads from the
distributor (photo).
17Disconnect the lead from the carburettor
fuel cut-off (anti-diesel) solenoid valve, where
applicable.
18Disconnect the lead from the oil pressure
switch (photo).
19Although not essential, removal of the
radiator is recommended as a precaution
against its damage during removal of the
power unit. Disconnect the wiring plugs from the fan and thermostatic switches
(photos).
20Disconnect the leads from the reversing
lamp switch on the transmission.
21Disconnect the clutch cable from the
release lever on the transmission.
22Disconnect the speedometer cable from
the transmission by unscrewing the knurled
ring.
23Working under the car, disconnect the
exhaust downpipes from the manifold and the
lower support bracket (photos).
24Disconnect the gearchange rods from the
levers on the transmission. One rod is
retained by a spring clip, the other by a
Supplement: Revisions and information on later models 13•27
5C.15 Ignition coil HT lead connection5C.12 Choke cable connection at
carburettor5C.9 Fuel hose identification at pump; inlet
hose (1), hose to carburettor (2), return
hose (3)
5C.19D Removing the radiator/fan
assembly5C.19C Radiator fan cut-out thermostatic
switch5C.19B Radiator fan motor wiring
connector
5C.19A Radiator retaining clip5C.18 Oil pressure switch5C.16 Coolant temperature switch
13

snap-on ball socket. Unbolt the gearchange
rod support bracket from the cover plate on
the flywheel housing (photos).
25Remove the screws from the driveshaft
inboard gaiter retaining plates (photos).
Expect slight oil loss.
26Disconnect the rear left-hand
transmission mounting. Do this by unscrewing
the two outer bolts not the centre one. The
engine will incline to the rear once the
mounting is released (photo).
27Raise the front of the car and support it
securely so that the front roadwheels hang
free.
28Remove the front roadwheels.
29Unscrew the tie-rod end balljoint taper pin
nuts, and then using a suitable “splitter” tool,
disconnect the balljoints from the eyes of the
steering arms.
30Unscrew the bolts from the clamps at the
bottom of the front suspension struts, tilt the
hub carriers outwards and partially disconnect
the driveshaft inboard joints from the
transmission.
31Support the weight of the engine/
transmission on a suitable hoist, and then
disconnect the right-hand and left-
hand front engine/transmission mountings
(photos).
32Unbolt and remove the engine mounting
brackets from the engine and the
transmission (photo).
33Raise the power unit slowly until the
driveshafts release from the transmission and
13•28 Supplement: Revisions and information on later models
5C.31B Left-hand engine mounting and
bracket5C.31A Right-hand engine mounting
disconnected5C.26 Left-hand rear (lower) transmission
mounting disconnected
5C.25B Driveshaft joint gaiter withdrawn5C.25A Two of the left-hand driveshaft
joint gaiter retaining plate screws
(arrowed)
5C.24C Gearchange rod support bracket5C.24B Gearchange rod with ball socket
connection
5C.24A Gearchange rod connecting pin
and spring clip5C.23B Unscrewing the exhaust pipe lower
support bracket bolt5C.23A Exhaust downpipe flange nuts

can be lowered to rest on the exhaust and
bodymember.
34Continue to raise the engine and the
transmission until it can be removed from the
engine compartment and placed on the work
surface (photo).
35Clean the exterior of the engine and
transmission by steam cleaning or using a
water soluble solvent.
36Unbolt and remove the starter motor.
37Unscrew the flywheel housing-to-engine
flange bolts. Note the location of the engine
lifting lug.
38Unbolt and remove the lower cover plate
from the flywheel housing.
39Pull the transmission from the engine. It is
located by two hollow dowels and one stud
(photo).
Dismantling - general
40Refer to Chapter 1, Section 14.
Complete dismantling#
Warning: Refer to the beginning
of Section 9 before starting any
work.
41Unbolt and remove the camshaft cover.
42Unbolt and remove the timing belt cover.
43Remove the distributor (Section 10).
44Remove the hot air collector and the
exhaust manifold.
45Release, disconnect and remove the
coolant distribution pipe from the rear of the
coolant pump.46Unscrew and discard the oil filter
cartridge.
47Unbolt the thermostat housing, discard
the joint gasket.
48Remove the fuel pump, together with its
insulator block and actuating pushrod, if
applicable.
49Remove the carburettor, or throttle body,
as appropriate.
50Remove the inlet manifold and discard the
joint gasket.
51Remove the alternator and its drivebelt
and withdraw the engine oil dipstick.
52Unbolt and remove the crankshaft pulley.
53Unbolt and remove the timing belt
tensioner.
54Remove the timing belt.
55Unbolt and remove the coolant pump.
56Remove the cylinder head.
57Remove and discard the cylinder head
gasket.
58Remove the clutch.
59Lock the flywheel starter ring gear teeth
and remove the crankshaft sprocket bolt and
sprocket.
60Unbolt and remove the sump pan,
then the exhaust pipe support bracket
(photos).
61Prevent rotation of the crankshaft by
locking the starter ring gear teeth and then
unbolt and remove the flywheel. The flywheel
can only be fitted in one position as it is
located on a dowel.
62Remove the engine rear plate. Note thesmall socket-headed screw which holds the
timing index plate (photo).
63Unbolt and remove the oil pump pick-up
assembly, followed by the oil pump itself.
64Turn the engine on its side and remove
the piston/connecting rod assemblies.
65Stand the engine on its cylinder block
machined face, and then unbolt and remove
the crankshaft rear oil seal retainer. Discard
the gasket.
66Note the markings on the main bearing
caps. One line on the cap nearest the timing
belt, then two, C for centre cap, then three
and four (photo).
67The caps will only fit one way round.
68Unbolt the main bearing caps, removing
them with the shell bearings.
69Lift the crankshaft from the crankcase and
remove the bearing half shells from the
Supplement: Revisions and information on later models 13•29
5C.39 Separating the engine and
transmission5C.34 Lifting out the engine and
transmission5C.32 Right-hand engine mounting
brackets on body and engine
5C.66 Main bearing cap markings
5C.60A Removing the sump pan
5C.62 Unscrewing socket-head screw
from timing index plate5C.60B Exhaust pipe support bracket
attached to crankcase
13

crankcase. If the shells are to be used again,
keep them with their respective bearing caps.
70The thrust washers which control
crankshaft endfloat are located in the
crankcase, and retained by the turned-over
edges of the centre main bearing shell.
71The engine is now fully stripped.
Examination and renovation
72The procedures for the following items are
essentially as described in Chapter 1, Sec-
tion 18.
Cylinder block and crankcase
Crankshaft and bearings
Flywheel
Oil seals and gaskets
Cylinder head
73Using a straight-edge, check the cylinder
head gasket surface for distortion. If it
exceeds the specified tolerance, it must be
surface ground by your dealer.74Refer to Chapter 1, Section 39, for
dismantling and renovation operations. Note
that single valve springs are fitted.
Oil pump
75Checking operations are described in
sub-Section B.
Pistons and connecting rods
76Refer to sub-Section B.
77If one or more connecting rods are
changed, it is important that its weight is
identical to that of the original. Use an
accurate balance to weigh them and remove
metal if necessary from the new rod in the
areas indicated in Fig. 13.7.
Camshaft and cam followers
78If the camshaft journals or bearings show
any sign of wear or scoring, then the
camshaft, or cylinder head, or both must be
renewed.
79The cam followers should be checked for
ovality using a micrometer. Unless unworn
they should be renewed.
Timing belt tensioner and timing belt
80The tensioner is a lubricant-sealed pulley,
and it should be tested for smooth and quiet
operation by turning it with the fingers. Any
evidence of roughness or rattle will indicate
the need for a new assembly (photo).81The timing belt should be inspected at
regular intervals for correct adjustment and
condition (see Section 3 or “Routine
maintenance” at the beginning of the Manual).
If there is evidence of worn teeth, cracking or
fraying, or oil contamination, renew the belt.
The vehicle manufacturers recommend that
the belt is renewed whenever it is removed,
and it should certainly be renewed at the
intervals specified in Section 3 or the main
“Routine maintenance” section at the
beginning of this Manual as a precautionary
measure against belt breakage and
consequent expensive engine damage.
PART D:
ENGINE REASSEMBLY AND
REFITTING
Reassembly - general
1Refer to Chapter 1, Section 19.
Complete reassembly#
2With the cylinder block/crankcase standing
on the work surface, fit the bearing half shells
into their crankcase seats (photo). Make sure
that the seats are perfectly clean as dirt or grit
trapped under the shell will cause binding
when the crankshaft is turned.
3The centre bearing crankcase web
incorporates the thrust washers held by the
lips of the bearing shell (photo).
4Oil the shells and lower the crankshaft into
the crankcase (photo).
5Fit the bearing shells into the main bearing
caps, again making sure that the shell seats
are perfectly clean (photo).
13•30 Supplement: Revisions and information on later models
5D.5 Main bearing cap and shell5D.4 Fitting the crankshaft5D.3 Crankshaft thrust washer at centre
bearing
5D.2 Main bearing shell in crankcase
Fig. 13.8 Checking a cam follower for
ovality - 999 and 1108 cc engine (Sec 5C)
Fig. 13.7 Metal removing areas (arrowed)
on connecting rod - 999 and 1108 cc
engine (Sec 5C)
5C.80 Timing belt tensioner

6Fit the main bearing caps in their numbered
sequence and the correct way round (photo).
7Clean the threads of the main bearing cap
bolts, lightly oil them and screw them in
finger-tight. Tighten all bolts progressively to
the specified torque, then check that the
crankshaft turns smoothly and evenly
(photos).
8Now check the crankshaft endfloat. Do this
using a dial gauge or feeler blades inserted
between the machined shoulder of a journal
and the side of the bearing cap (photo). Move
the crankshaft fully in one direction and then
the other to ensure that full movement is
obtained. If the endfloat is outside the
specified tolerance and new bearing shellshave been fitted, then a fault must have
occurred during crankshaft regrinding.
9Fit a new oil seal to the crankshaft rear oil
seal retainer. Apply grease to the seal lips. A
conventional gasket is not used at the oil seal
joint face but a 3.0 mm diameter bead of RTV
silicone instant gasket must be applied
to a clean surface as shown in Fig. 13.9
(photo).
10Bolt the retainer into position. One hour at
least must be allowed for the RTV to cure
before oil contacts it.
11Turn the engine on its side and fit the
piston/connecting rods as described in
sub-Section B.
12Fit a new oil seal to the oil pump, oil theseal lips and bolt on the pump using a new
joint gasket (photos).
13Use a new sealing washer and fit the oil
pick-up/filter screen assembly.
14Fit the engine rear plate and then the
flywheel on its mounting flange. Apply
thread-locking fluid to (clean) bolt threads and
screw in the bolts to the specified torque
(photo). Hold the flywheel against rotation by
locking the starter ring gear with a suitable
tool.
15Fit the sump pan as described in
sub-Section B.
16Fit the crankshaft sprocket so that the
timing mark is visible. Lock the flywheel
starter ring gear teeth, and screw in and
Supplement: Revisions and information on later models 13•31
5D.7B Angle-tightening a main bearing cap
bolt5D.7A Initial tightening of a main bearing
cap bolt5D.6 Fitting a main bearing cap
5D.14 Tightening a flywheel bolt5D.12B Tightening an oil pump bolt5D.12A Oil pump gasket
5D.9 Fitting crankshaft rear oil seal
retainerFig. 13.9 Application area for silicone
gasket on crankshaft rear oil seal retainer
(Sec 5D)5D.8 Checking crankshaft endfloat using a
dial gauge
13

tighten the sprocket bolt to the specified
torque (photos).
17Refit the clutch to the flywheel asdescribed in Chapter 5. Make sure that the
driven plate is centralised.
18Fit the cylinder head.
19Refit the coolant pump. A conventional
gasket is not used at the joint face, but apply
a continuous bead of RTV silicone instant
gasket 3.0 mm in diameter to the pump
mating surface. Allow at least one hour for
curing before permitting coolant to contact it.
20Fit the timing belt rear cover, then the
timing belt tensioner and lock in its retracted
position (photo).
21Fit and tension the timing belt as
described in sub-Section B.
22Bolt on the crankshaft pulley (photo).
23Refit the alternator and drivebelt (photo).
24Refit the engine oil dipstick.
25Using a new gasket, bolt on the inletmanifold, tightening the nuts to the specified
torque (photos).
26Refit the carburettor, or throttle body, as
appropriate.
27Fit the fuel pump, insulator block and
actuating rod, if applicable. Make sure that a
new gasket is placed on each side of the
pump insulator block.
28Using a new gasket, bolt on the
thermostat housing.
29Oil the sealing ring of a new oil filter
cartridge and screw it into position using hand
pressure only (photo).
30Refit the coolant distribution pipe to the
rear of the coolant pump. Use a new seal
(photo).
31Using a new gasket, bolt on the exhaust
manifold (photo).
13•32 Supplement: Revisions and information on later models
5D.31 Exhaust manifold5D.30 Coolant distribution pipe5D.29 Oil filter cartridge and mounting
base
5D.25B Fitting the inlet manifold5D.25A Inlet manifold gasket5D.23 Alternator and drivebelt
5D.22 Crankshaft pulley installation
5D.20 Fitting the timing belt rear cover5D.16B Tightening the crankshaft sprocket
bolt5D.16A Crankshaft sprocket showing
integral key

32Fit the hot air collector plate for the air
cleaner (photo).
33Refer to Section 10 and fit the distributor.
34Bolt on the timing belt cover.
35Fit the camshaft cover, using a new
gasket unless the original one is in perfect
condition.
Engine/transmission -
reconnection and refitting#
36Locate the engine in an upright position
on wooden blocks to allow for the greater
depth of the transmission flywheel housing
when it is joined to the engine.
37Make sure that the clutch driven plate has
been centralised, offer the transmission to the
engine and locate the flywheel housing on the
single stud and dowels.
38Tighten the connecting bolts to specifiedtorque, having located the lifting eye (photo).
39Bolt on the starter motor.
40Refit the cover plate to the flywheel
housing, but do not insert the lower bolts at
this stage as they retain the support bracket
for the gearchange rod.
41The engine and transmission are now
ready for refitting. The operations are a direct
reversal of the operations described earlier,
but observe the following points.
42Have the engine/transmission perfectly
horizontal and suspended on the hoist.
43Lower it into position very slowly until it is
possible to engage the driveshaft inboard
joints with the transmission.
44Continue lowering until the driveshafts
can be fully engaged and the mountings
reconnected. Remove the hoist.
45Tighten all nuts and bolts to the specifiedtorque. Note the method shown for
connecting the gearchange rod ball socket
using pliers (photo).
46Refill the engine with oil and coolant and
replenish the transmission oil.
Initial start-up after major
overhaul
47Refer to Chapter 1, Section 45.
6 Engine-
1301 cc Turbo ie
PART A: GENERAL
Description
1This engine is similar in design to the
1301 cc engine described in Chapter 1, but
the fuel and ignition systems are different, and
a turbocharger, oil cooler and intercooler are
fitted.
2Many dimensions and tolerances have
been altered for this engine, and reference
should be made to the Specifications at the
beginning of this Supplement.
3Operations which differ from those
described in Chapter 1 are given in the
following sub-Sections.
Lubrication system - description
4The lubrication system differs from the
non-Turbo 1301 cc engine in the following
respects.
5An oil cooler is fitted, which comprises a
matrix with inlet and outlet hoses connected
to the oil filter cartridge mounting base.
6A thermostatic control switch is fitted,
which diverts the oil flow through the matrix
only at oil temperatures above 84ºC (183ºF).
Note that a faulty switch will require renewal
of the complete oil filter mounting base.
7Special oil spray nozzles are located in the
crankcase main bearing webs, to cool the
underside of the pistons.
8The ball-type valves in the nozzles open
when the engine oil pressure reaches 1.2 bars
(17.4 lbf/in
2).
9An oil pressure sender unit is screwed into
Supplement: Revisions and information on later models 13•33
5D.45 Connecting ball socket type
gearchange rod5D.38 Lifting eye on flywheel housing
flange5D.32 Air cleaner hot air collector plate
Fig. 13.10 Cutaway view of the 1301 cc Turbo ie engine (Sec 6A)
13

the crankcase to operate the oil pressure
gauge. In addition, a low oil pressure switch
screwed into the camshaft oil gallery actuates
a warning light on the instrument panel in theevent of the pressure dropping dangerously
low (photo).
10Oil supply/return ducts provide the
turbocharger lubrication.
PART B:
OPERATIONS POSSlBLE
WITH ENGINE IN CAR
Camshaft and camshaft
carrier - removal and
refitting
#
Warning: Refer to the beginning
of Section 9 before starting any
work.
1Disconnect the battery, negative lead first.
2Disconnect its leads and unbolt the
distributor from the end of the camshaft, and
place it to one side.
3Disconnect the air intake hose from the
throttle valve housing.
4Disconnect the short throttle control cable
from its sector.
5Remove the throttle cable support bracket.
6Disconnect the earth leads from the
camshaft cover.
7Refer to Section 9, Part C of this
Supplement and remove the following
components.
Supplementary air valve
Inlet manifold with fuel pressure regulator
and excess pressure safety switch
Injector cooling duct
8Disconnect the wiring plug from the
Microplex ignition anti-knock sensor.
9Carry out the operations described in
Chapter 1, Section 27, paragraphs 4 to 12.
10Refitting is a reversal of removal, referring
to Section 28 of Chapter 1 for the timing belt
refitting procedure, and to Chapter 1, Sec-
tion 27, paragraphs 15 to 18.
Cylinder head -
removal and refitting#
11Carry out the operations described in
paragraphs 4 to 9 in the preceding
sub-Section, then refer to Chapter 1, Section
29, but ignore all references to the
carburettor.
12Note the distributor mounting cover.
13Four additional cylinder head bolts are
used on these engines, adjacent to the spark
plugs (photo). Note that their tightening torque
differs from the other cylinder head bolts - see
Specifications. These four bolts are tightened
13•34 Supplement: Revisions and information on later models
1 Oil pick-up strainer
2 Oil pump
3 Oil pressure relief valve
4 Oil filter cartridge
5 Main oil gallery6 Camshaft oil feed
7 Low oil pressure switch
8 Engine oil cooler
9 Filter mounting base
10 Turbocharger oil feed11 Turbocharger oil return
12 Oil pressure sender unit
13 Oil temperature sender
unit
14 Piston oil spray nozzle
Fig. 13.12 Piston oil spray nozzle locations - 1301 cc Turbo ie engine (Sec 6A)
Letters denote cylinder bore grade
Fig. 13.11 1301 cc Turbo ie engine lubrication system (Sec 6A)
6A.9 Oil pressure sender unit

separately, after the ten main bolts (see
Fig. 13.13).
Piston rings
14The piston rings comprise two
compression rings marked TOP, and an oil
control ring.
15Cross-sections and fitting details are
shown in Fig. 13.14.
Engine mountings - renewal
16The operations are essentially as
described in Section 33 of Chapter 1, but note
the design and fixings of the individual
mountings used on the turbocharged engine
(photos).
Timing belt - renewal#
17The operations described in Chapter 1,
Section 28 generally apply, but the following
differences should be noted.18Remove the engine compartment
right-hand shield. This is secured by plastic
clips. To remove a clip, push out its centre
pin.
19The TDC sensor must be unbolted to
provide room to remove and refit the timing
belt, which can be carried out without
having to remove the crankshaft pulley
(photos).
20The belt tensioner on later versions
does not incorporate a spring, but is of
eccentric centre bolt hole type. Have the
pulley bolt released, and tension the belt by
turning the pulley using a pin wrench or
circlip pliers in the two holes provided.
Keep the tension applied while the lockbolt
is tightened. Turn the crankshaft through
two complete turns, and then check the belt
tension. With moderate finger and thumb
pressure, the belt should just twist through90º when gripped at the mid-point of its
longest run (photo). Note: This procedure
serves only as a rough guide to setting the
belt tension - having it checked by a FIAT
dealer at the earliest opportunity is
recommended.
Oil pump drivegear cover plate
21Due to the fact that the distributor is
driven from the end of the camshaft, the oil
pump gear does not have an extension to
drive the distributor, which would be the case
if it was mounted on the crankcase.
22The crankcase aperture is therefore
covered by a plate and gasket, together with a
wiring clip (photo).
Supplement: Revisions and information on later models 13•35
6B.13 Two of the four additional cylinder
head bolts (arrowed)
Fig. 13.14 Piston ring arrangement on the
1301 cc Turbo ie engine (Sec 6B)Fig. 13.13 Cylinder head bolt tightening
sequence on the 1301 cc Turbo ie engine
(Sec 6B)
6B.22 Distributor drive hole cover plate
(arrowed)6B.20 Belt tensioner pulley locknut
(arrowed)6B.19B Removing the timing belt
6B.19A Removing the TDC sensor6B.16B Engine/transmission right-hand
mounting6B.16A Engine/transmission centre
mounting
13