Gear FIAT 127 1977 1.G Workshop Manual

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Supplement

Contents

Introduction ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... 1

Specifications ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... 2

Engine … … … ... ... ... ... ... ... ... ... ... . .. ... ... ... ... ... ... ... ... ... ... ... 3
1049 cc engine - general
Crankshaft - refitting
Piston rings - refitting
Pistons and connecting rods - reassembly
Pistons - refitting
Connecting rods to crankshaft - reassembly
Oil pump - reassembly
Crankshaft oil seals and carriers - refitting
Sump - refitting
Auxiliary shaft and seal - refitting
Belt - pulleys and tensioner - refitting
Cylinder head and valve gear - reassembly
Distributor - refitting
Toothed drive belt - removal, refitting and adjust ing
Valve clearances - adjustment
Engine - final assembly
Engine removal – 127 Special and 127 from chassis number 1104290 onwards

Fuel system ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... 4
Carburettors - general
Weber or Solex single venturi carburettors
Weber dual venturi carburettor
Carburettor overhaul - general

Ignition system... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... ... 5
Automatic centrifugal advance curves
Braking system... ... ... ... ... ... ... ... ... . .. ... ... ... ... ... ... ... ... ... ... ... 6
Brake fluid reservoir and vacuum servo unit (Sport )

Electrical system... ... ... ... ... ... ... ... .. . ... ... ... ... ... ... ... ... ... ... ... . 7
Charging system
Fuses (127 Special)
Fuses (1049 cc models)
Bodywork and fittings ... ... ... ... ... ... ... . .. ... ... ... ... ... ... ... ... ... ... 8
Model variations
Wing mouldings and front spoiler (Sport) - removal and refitting
Rear spoiler (Sport) – removal and refitting

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Crankshaft inches mm
Main bearing journal diameter 1.8972 to 1.898 48.1 89 to 48.209
Standard main bearing shell thickness 0.0721 to 0.0 726 1.831 to 1.845
Main bearing shell undersize range 0.01; 0.02; 0.03 ; 0.04 0.254; 0.508; 0.762; 1.016

Standard crankpin diameter 1.7318 to 1.7326 43.988 to 44.008
Main bearing journal fit clearance 0.0009 to 0.033 0.022 to 0.083
Width of centre main bearing cap between
thrust washers 1.2785 to 1.2805 32.475 to 32.525
Standard thrust washers thickness 0.0909 to 0.0929 2.31 to 2.36
Thrust washers oversize range 0.0959 to 0.0979 2.43 7 to 2.487
Crankshaft endfloat 0.0022 to 0.0104 0.055 to 0.265
Maximum misalignment of main bearing
journals 0.0012 0.030
Maximum misalignment of main bearing
journals to crankpins 0.0138 0.350
Maximum ovality of crankpins and main
bearing journals after grinding 0.0002 0.005
Maximum taper of crankpins and main
bearing journals after grinding 0.0002 0.005
Maximum run-out of crankshaft flange with
dial gauge stylus 31 mm (1.22 ins) from
crankshaft rotational axis 0.001 0.025
Maximum run-out between flywheel face
and crankshaft flange, and between
flywheel face and crankshaft axis 0.0039 0.10

Cylinder head inches mm
Standard valve guide housing bore 0.5886 to 0.5896 14.950 to 14.977
Standard valve outside diameter 0.5921 to 0.5928 15 .040 to 15.058
Oversize valve guide 0.002; 0.0039; 0.0098
0.05; 0.10; 0.25
Valve guide interference fit 0.0025 to 0.0043 0.063 to 0.108
Fitted valve guide internal diameter 0.3158 to 0.31 65 8.022 to 8.040
Valve stem diameter 0.3139 to 0.3146 7.974 to 7.992
Valve stem fit clearance in guide 0.0012 to 0.0026 0.030 to 0.066
Valve head diameter:
Inlet (C, L and CL) 1.3327 to 1.3445 33.85 to 34 .15
Inlet (Sport) 1.4311 to 1.4429 36.35 to 36.65
Exhaust 1.1358 to 1.1476 28.85 to 29.15
Valve seat width 0.0787 to 0.0866 2.0 to 2.2
Valve seat internal diameter:
Inlet (C, L and CL) 1.1063 to 1.1142 28.1 to 28. 3
Inlet (Sport) 1.2244 to 1.2323 31.1 to 31.3
Exhaust (C, L and CL) 0.9882 to 0.9961 25.1 to 2 5.3
Inlet (Sport) 1.0276 to 1.0354 26.1 to 26.3
Angle of valve seat 45° ± 5'
Angle of valve face 45° 30' ± 5'
Valve springs:
Inner spring part no. 4134900
Outer spring part no. 4170458
Valve gear inches mm
Camshaft journal diameter:
Valve gear end 1.1789 to 1.1795 29.945 to 29.96 0
Centre 1.0630 to 1.0636 27.000 to 27.015
Flywheel end 0.9843 to 0.9848 25.000 to 25.015

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Camshaft bearing bore diameter in head:
Valve gear end 1.1807 to 1.1817 29.990 to 30.015
Centre 1.0648 to 1.0657 27.045 to 27.070
Flywheel end 0.9860 to 0.9870 25.045 to 25.070
Camshaft journals fit clearance 0.0012 to 0.0028 0. 030 to 0.070
Cam lift (C, L and CL) 0.3425 8.700
Cam lift (Sport):
Inlet 0.3622 9.200
Exhaust 0.3642 9.250
Standard tappet bore diameter 1.4567 to 1.4577 37.0 00 to 37.025
Standard tappet outside diameter 1.4557 to 1.4565 36.975 to 36.995
Tappet fit clearance 0.0002 to 0.0020 0.005 to 0.05 0
Shim thickness 0.1279; 0.1299; then
0.0039 steps to 0.1850

3.2b; 3.30; then
0.10 steps to 4.70

Auxiliary shaft inches mm
Diameter of bush bores in crankcase:
Front 1.6339 to 1.6350 41.500 to 41.530
Rear 1.5733 to 1.5745 39.962 to 39.992
Fitted bush internal diameter:
Front 1.5143 to 1.5151 38.464 to 38.484
Rear 1.4553 to 1.4561 36.964 to 36.984
Diameter of shaft journals:
Front 1.5115 to 1.5125 38.393 to 38.418
Rear 1.4525 to 1.4535 36.893 to 36.918
Bush fit There must always be an interference fit
Shaft/bush fit clearance (front and rear) 0.0018 to 0.0036 0.046 to 0.091
Lubrication system
Oil pump Four lobe rotor type
Pump drive Through auxiliary shaft
Oil pressure relief valve Incorporated in pu mp
Pump rotors endfloat 0.0018 to 0.0047 0.045 to 0.120
Outer rotor to body clearance 0.0006 to 0.002 2 0.016 to 0.055
Inner to outer rotor clearance 0.0010 to 0.00 39 0.025 to 0.100
Oil pressure at 212°F (100°C) 50 to 70 Ibf/in
2 (3.5 to 5 kgf/cm2)

Cooling system
Radiator fan thermal switch
Cuts in . 194° to 201°F (90° to 94°C)
Cuts out 185° to 192°F (85° to 89°C)
Engine coolant thermostat
Starts to open 176° to 183°F (80° to 84°C)
Fully open 205°F (96°C)
Impellor vanes to pump body fit clearance 0.0315 to 0.0512 in (0.8 to 1.3 mm)

Radiator cap relief pressure 11.4 Ibf/in
2 (0.8 kgf/cm2)

Fuel system
Weber 32 ICEV 16/150 carburettor (C, L and CL model s)
Venturi diameter 0.8465 in (21.5 mm)
Main jet . 0.0453 in (1.15 mm)

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Maximum run-out of driven plate linings 0.2 mm (0.008 in)

Travel of release flange, corresponding
to a pressure plate displacement of not less
than 0.067 in ~1.7 mm) 8.5 mm (0.3346 in)

Transmission
Synchromesh 1st and 2nd, Borg-Warner baulk ring type,
3rd and 4th, Porsche spring ring type

Gear ratios
First 3.910 : 1
Second 2.055 : 1
Third 1.348 : 1
Fourth 0.963 : 1
Reverse 3.615 : 1

Final drive ratio (C,L and CL) 4.071 : 1 (14/57)

Final drive ratio (Sport) 4.462 : 1 (13/58)

Overall ratios
Gears 1st 2nd 3rd 4th Reverse
C, L and CL 15.92 8.7 5.49 3.92 14.72
Sport 17.45 9.17 6.01 4.30 16.13

Electrical system
Alternator
Type (C, L and CL) Magneti Marelli AA 108-14V-33A
Type (Sport) Lucas 18ACR-A4V-45A
Maximum output (approx) 570 watts
Maximum current (approx) 40 amps (C, L and CL) 50 amps (Sport)
Cut-in speed at 12V and 20°C (68°F) 1050 to 1150 r pm (C, L and CL)
1100 to 1200 rpm (Sport)
Field winding resistance across slip rings at 20°C (68°F) 3.4 to 3.8 ohms (C, L and CL)
3.18 to 3.22 ohms (Sport)
Direction of rotation (drive end) Clockwise
Engine/alternator drive ratio 1.8 : 1
Alternator regulator (C, L and CL models)
Type Magneti Marelli RTT 110 AB
Alternator speed for adjustment 6000 rpm
Current for thermal balance 20 amps
Regulating voltage 14.2
+0.3
–0.2 volts

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Lamps
Headlamps (C, L and CL)
Headlamps (Sport)
Brake and rear light
Turn indicators
Reversing lights
Parking lights
Number plate
Courtesy light
Boot light
Turn repeaters
Cigar lighter light
Instrument panel
Ignition warning
Turn indicator warning
Headlamp warning
Coolant temperature warning (L models)
Oil pressure warning
Fuel warning
Hazard warning
Sidelamp (out) warning (Sport only)
Brake warning (Sport only)
Heated rear window warning (Sport only)
40/45 watts
55/60 watts (Halogen)
5/21 watts
21 watts
21 watts
5 watts
5 watts
5 watts
5 watts
4 watts
4 watts
3 watts
3 watts
1.2 watts
1.2 watts
1.2 watts
1.2 watts
1.2 watts
1.2 watts
3 watts
1.2 watts
1.2 watts

Fuses
For fuse details (127 Special, L, C, CL and Sport) see Sections 23 or 24

Steering and suspension (Sport only)
Steering angles
Inner wheel 34° 50’
Outer wheel 32° 10’
Front wheel alignment (toe setting)
Laden 0.079 in (2.0 mm) toe-in to 0.079 in (2.0 mm) toe-o ut
Unladen 0.138 in (3.5 mm) to 0.217 in (5.5 mm) toe-in

Roadwheels
Size 4½ B x 13
Tyres 135 SR-13 or 155/70 SR-13

All 1049 cc models Ibf ft kgf m
Main bearing cap bolts 59 8.2
Engine mounting securing bolts 43 6
Cylinder head to block bolts and nuts:
1 st stage 30 4.1
2nd stage 45 6.2
Final stage 61 8.5
Manifold to head nuts 20 2.8
Connecting rod big-end nuts 38 5.2
Flywheel to crankshaft bolts 61 8.5
Driven gear (Plastic) to camshaft retaining bolt 87 12
Driven gear (steel) to camshaft retaining bolt 87 1 2
Camshaft cap nuts 14 2

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Ignition distributor clamp nut 11 1.5
Oil pump to crankcase bolts 13 1.8
Cylinder head outlet pipe bolt 16 2.2
Water pump/alternator drive pulley nut 101 14
Alternator bracket to crankcase bolt 20 2.8
Alternator to lower bracket bolt 36 5
Cylinder head upper bracket bolt 20 2.8
Alternator to upper bracket nut 36 5
Upper bracket securing bolt 13 1.8
Oil pressure switch 24 3.3
Coolant temperature switch 36 5
Spark plug 27 3.8

Sport models only
Engine
Flexible mounting to body (engine side) 65 9.0
Flexible mounting support (engine side to body)
18 2.5
Flexible mounting upper support to gearbox 18 2.5
Engine crossmember to body 18 2.5
Flexible mounting support nut (gearbox side) 18 2.5
Flexible mounting support bolt to body
(gearbox LH side) 65 9.0
Steering and suspension
Steering wheel retaining nut 22 3.0
Front wheel bearing ring nut 44 6.0
Front wheel hub nut 160 22.0
Roadwheel bolts 64 8.8
Front suspension track control arm to body 20 2.7
Front suspension balljoint to hub carrier 40 5.5
Rear wheel hub nut 160 22
Transmission
Starter motor bolt to bellhousing lower support 18 2.5
Gear selector shaft nut 18 2.5
Upper gear lever relay lever 22 3.0
Idler support securing nut 18 2.5
Differential case flange to gearbox housing 18 2.5

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3.8 The half thrust washers are fitted each side of
the
centre bearing


3.9 Oil the bearings and crankshaft journals…





3.10 … and then fit the crankshaft into the crankca se 12 Refit the main bearing cap bolts and screw
them up fingertight. Spin the crankshaft and, if
all is well, tighten the bolts to the specified
torque load and turn the crankshaft again to
check freedom of rotation (photo).
13 Measure the crankshaft endfloat with feeler
gauges. If this exceeds the specified tolerance,
oversize thrust washers will have to be fitted.
Pision rings - refitting
14 Follow the procedure given in Chapter 1,
Section 42.
Pistons and connecting rods–reassembly
15 Follow the procedure given in Chapter 1,
Section 43 (photo).
Pistons – refitting
16 Follow the procedure given in Chapter 1,
Section 44.
17 Note that the connecting rods in the 1049 cc
engine have two oil jet holes leading from the
big-end bearing (photo).
18 When the piston is correctly fitted it will have

the valve depressions adjacent to the side of the
block with the cylinder head studs in (photo). C
onnecting rods to crankshaft-
r
eassembly
19 Follow the procedure given in Chapter 1,
Section 45.
20 Torque load the big-end cap nuts to the
reading quoted in the Specifications of this
Chapter 13 - it is different from the value quoted
for the 903 cc engine (photo).
Oil pump - reassembly
21 The oil pump fitted to the 1049 cc engine is a
Hobourn-Eaton rotor type of pump which is quite
different from the gear pump fitted to the 903 cc
engine. It consists of a four lobed rotor rotating
in a five slotted outer rotor which is mounted
eccentrically to the inner rotor. As the inner roto r
rotates the outer rotor is driven round, and the
spaces between the lobes on the inner rotor and
the slots in the outer rotor increase and
decrease once per revolution. The increasing
spaces are connected to the pump inlet and
cause oil to be drawn into the pump. The
decreasing spaces connect with the pump outlet
through which the oil is forced to feed the
engine. A springloaded relief valve in the outlet
of the pump vents excessive oil pressure into
the sump. The efficiency of the pump depends

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32 Carefully ease the lip of the seal onto the
spigot and secure the carrier with the bolts and
washers (photo).
33 Similarly clean the crankshaft at the timing
belt end and fit the seal and carrier. Retain by
the two bottom bolts (photo). 34 Put the timing
indicator bracket over the two top bolt holes in
the seal carrier and fit the two top bolts (photo).

Sump - refitting
35 Make sure that there are no remnants of the
old gasket on the sump flange and fit a new
gasket using a little grease to hold it in position .
Check that it is bedded down evenly all round
the flange.
36 Fit the sump to the crankcase. Put the load
spreading washers on each bolt and screw into
the crankcase (photo).
37 Tighten the bolts evenly to avoid warping the
flange.
Auxiliary shaft and seal - refitting
38 Clean the auxiliary shaft bearings and
lubricate with clean engine oil.
39 Insert the shaft into the crankcase bushes
and rotate the shaft to spread the oil (photo).
40 Lubricate the auxiliary shaft seal in its carrie r
and carefully ease the seal over the shaft spigot
(photo).
41 Fit the seal carrier retaining bolts and
washers and tighten.
Belt pulleys and tensioner - refitting
42 Fit the toothed pulley to the auxiliary shaft.
The recess in the pulley fits on the auxiliary shaf t
with the dowel on the shaft in the hole in the
pulley (photo). Fit the retaining bolt and washer
and partially tighten, as it will be necessary to
wait until the drivebelt has been fitted before
finally tightening this bolt. Alternatively, it is
possible to hold the auxiliary shaft carefully in a
vice, fit the seal and carrier to the shaft, follow ed
by the toothed pulley and its retaining bolt and
washer, and then tighten the bolt fully before
fitting the complete assembly to the block.
43 The belt tensioner bracket can now be fitted.
Clean off all traces of old gasket from the
bracket and block and use a new gasket on
assembly. Fit the retaining bolts and washers
and tighten (photo).
44 Insert the spring-loaded plunger assembly
into the tensioner bracket (photo).
45 The tensioning wheel in its carrier can now
be fitted. Put the top bolt and washer in first and
then bear down to compress the spring and fit the bottom bolt through the kidney-shaped slot.
Note that this latter bolt has an additional, large
washer against the wheel carrier. Temporarily
tighten the two bolts they will have to be
retightened after the belt has been fitted (photo).

46 If the key had previously been removed from
the pulley end of the crankshaft, clean the key
slot and refit the key. Then slide on the bevelled
washer, making sure that the bevel is on the
side away from the crankcase (photo).
47 Refit the crankshaft toothed pulley (photo).
Then the V-belt pulley can be refitted together
with its retaining nut and washer. Final
tightening of this nut can wait until the flywheel
has been fitted, when a 'gag' can be fitted to the
flywheel to hold the crankshaft whilst tightening
the nut - see Chapter 1, photo 23.2A.

Cylinder head and valve gear-reassembly

48 It is assumed that the valves will have
already been examined and renovated as
described in Chapter 1, Section 31. Follow the
procedure given in Chapter 1, Section 51 to
reassemble the valves, but note that new oil
seals should be fitted to this engine when the
valves have been inserted in the guides and
before the springs are fitted (photos).
49 Each tappet bucket contains a shim in the
head which is used to control the valve
clearance. Before assembling the buckets to
their valves, prise out each shim and take a note
of the thickness. This is etched on the lower face
of the shim and indicates the thickness in
millimetres to two decimal places. If the number
has worn off, use a micrometer to check the
shim thickness. Make a table showing each
valve by number and the thickness of shim on
assembly. Reassemble each shim to its bucket
and after lubricating with clean engine oil fit the
buckets to their respective valves (photos).
50 Lubricate the two camshaft bearings in the
cylinder head and carefully thread the camshaft
through the driving end hole and lower it onto its
bearings. The cams will rest on the tappet
buckets and the camshaft should now be turned
so that the two cams over No. 1 cylinder (driving
end) are pointing upwards (compression/firing
stroke). This is to reduce the bending load on
the camshaft as the two bearing halves are
being tightened down (photo).
51 Lubricate the camshaft bearing halves and fit
them to their respective studs in the head. Put
the steel bridge plates in position and fit the
washers and nuts (photo).
52 Tighten the four nuts a little at a time

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3.68 Fitting the distributor



3.70 Distributor clamp bolt


extension length and the torque wrench length
and is calculated by using the formula:

where A is the specified torque loading (Ibf ft or
kgf m), B is the torque to be set, or read, when
using an extension (Ibf ft or kgf m), y is the
length of extension (ft or m), and z is the length
of torque wrench (ft or m).
Example: Specified torque is 60 Ibf ft, length of
extension is 6 in, and length of torque wrench is
2 ft, then B = (60 x 2) = (6/12 + 2) = 120 =2'/z =
48 Ibf ft; torque wrench setting or indication.
When measuring, use centres of bolts/nuts and
centre of torque wrench drive square. When
calculating, keep values constant, that is, don't
mix inches and feet for example (photos). 63 Fit
the drivebelt as described later in this Section.
When fitted, the auxiliary shaft pulley bolt and
the camshaft pulley bolt can be torque loaded to
the specified settings if these were not done on
assembly.
Distributor - refitting
64 The distributor is mounted nearly vertical on
the oil filter side of the engine and is driven by
skew gears from the auxiliary shaft. In turn the
distributor shaft also drives the oil pump through
a splined coupling (photo).
65 It is more convenient to set the contact
breaker gap before fitting the distributor to the
engine. Adjust to the specified clearance
(photo).
66 Turn the crankshaft in the normal direction of
rotation until the line on the crankshaft pulley is
adjacent to the first of the three pointers on the
timing bracket. This is 100 BTDC, the second
pointer is 50 BTDC and the large, third pointer is
TDC. Note which cylinder, either 1 or 4, is on the
compression stroke. This is indicated by both of
the inlet and exhaust cams pointing upwards
causing their relative valves to be shut. 67
Rotate the distributor shaft until the rotor is
opposite the terminal in the distributor cap
serving the same cylinder number as the one
which was on compression stroke and with the
contact breaker points just breaking.
68 Lubricate the distributor skew gear with clean
engine oil and insert the distributor into the
engine block. Watch the rotor carefully to see
how much it turns as the skew gears mesh.
Then withdraw the distributor, reset the rotor and
then preset it the same amount that it turne d


3.77 Fitting the toothed drivebelt-crankshaft V-bel t pulley
removed for clarity

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3.60 The cylinder head gasket is fitted ALTO upward s 3.61 Lower the cylinder head onto the block



3.62A Tighten the cylinder head bolts and nuts to t he
specified torque 3.62B These cylinder head nuts might be difficult
to torque
tighten


3.64 Distributor driveshaft skew gear 3.65 Checkin g the contact breaker gap