1981 FIAT 127 Valve

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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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2. Specifications

Capacities (1049 cc models )
Engine oil (including filter change)
L, C and CL ... ... ... ... ... ... ... ... … 5.5 pints (3.1 litres)
Sport ... ... ... ... ... ... ... ... ... 7.7 pi nts (4.4 litres)

Coolant ... ... ... ... ... ... ... ... … 9.7 pints (5.5 litres)

Fuel ... ... ... ... ... ... ... ... … 6.7 gallons (30 .5 litres) including 6.2 pints
(3.5 litres) reserve

Transmission oil ... … ... ... ... ... ... ... . 4.2 pints (2.4 l itres)


1049 cc OHC engine
General
Type number ... ... ... ... ... ... ... ... … 127 A 000 (C, L and CL);
127 A1.000 (Sport)
Bore ... ... ... ... ... ... ... ... … 2.992 in (76 mm)
Stroke ... ... ... ... ... ... ... ... ... 2.276 in (57.8 mm)
Capacity ... ... ... ... ... ... ... ... … 64 cu in (1049 cc)
Compression ratio ... ... ... ... ... … 9,3 : 1 (C, L and CL);
9,8 : 1 (Sport)
Maximum horsepower (DIN) ... ... ... ... 50 HP a t 5600 rpm (C, L and CL);
70 HP at 5600 rpm (Sport)

Valve mechanism C, L and CL Sport
Inlet :
Opens ... ... ... ... ... ... ... ... ... 2° B TDC 6° BTDC
Closes ... ... ... ... ... ... ... ... ... 42° ABDC 46°ABDC
Exhaust :
Opens ... ... ... ... ... ... ... ... ... 42° BBDC 47° BBDC
Closes ... ... ... ... ... ... ... … … 2° ATDC 7° ATDC
Valve clearances (cold) :
For checking valve timing:
Inlet ... ... ... ... ... ... ... ... 0.02 8 in (0.70 mm) 0.032 in (0.80 mm)
Exhaust ... ... ... ... ... ... ... 0.028 in (0.70 mm) 0.032 in (0.80 mm)
Adjustment for running (engine cold) :
Inlet ... ... ... ... ... ... ... ... 0.01 2 in (0.30 mm) 0.016 in (0.40 mm)
Exhaust ... ... ... ... ... ... ... 0.016 i n (0 40 mm) 0.020 in (0.50 mm)

Cylinder block and connecting rods inches mm
Cylinder bore diameter * 2.992 to 2.994 76.00 to 7 6.05
* Cylinder bores are graded and have a variation of 0.0004 inch (0.01 mm) between each grade
Main bearing housing bore diameter 2.044 to 2.045 51.921 to 51.934
Width of centre main bearing cap between

thrust washers 1.088 to 1.091 27.64 to 27.70
Connecting rod big-end diameter 1.85 to 1.8560 47. 130 to 47.142
Connecting rod small-end diameter 0.8638 to 0.8646 21.94 to 21.96
Big-end bearing shell thickness 0.0606 to 0.8646 1. 539 to 1.55

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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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Air correction jet 0.0728 in (1.85 mm)
Slow running jet 0.0177 in (0.45 mm)
Emulsion tube type F74
Accelerator pump jet 0.0157 in (0.40 mm)
Needle valve seat 0.0591 in (1.50 mm)
Accelerator pump output (10 strokes) 2 to 3 cm
3
Cold starting device Automatic choke
Float level 1.4016 to 1.4213 in (35.6 to 36. 1 mm)
CO level 2.5%

Solex C32 TDI/4 carburettor (C, L and CL models)
Venturi diameter 0.8465 in (21.5 mm)
Main jet 0.0453 in (1.15 mm)
Air correction jet 0.0768 in (1.95 mm)
Slow running jet 0.0177 in (0.45 mm)
Emulsion tube type 71
Accelerator pump jet 0.0177 in (0.45 mm)
Needle valve seat 0.0630 in (1.60 mm)
Accelerator pump output I10 strokes) 3 to 5 cm
3
Cold starting device Automatic choke
Float level 0.8661 to 0.9449 in (22.0 to 24. 0 mm)
CO level 2.5%

Weber 34 DMTR 47/250 carburettor (Sport models) Primary venturi Secondary venturi
Venturi diameter 0.8661 in (22.0 mm) 0.9449 in (24.0 mm)
Main jet 0.0421 in (1.07 mm) 0.0500 in (1. 27 mm)
Air correction jet 0.0728 in (1.85 mm) 0.086 6 in (2.20 mm)
Slow running jet 0.0177 in (0.45 mm) 0.0276 in (0. 70 mm)
Slow running air bleed 0.0413 in (1.05 mm) 0.027 6 in (0.70 mm)
Accelerator pump jet 0.0157 in (0.40 mm) ---
Needle valve seat 0.0689 in (1.75 mm)
Accelerator pump output (10 strokes) 8.55 cm
3
Cold starting device Manually operated strangler ch oke
Float level 0.2657 to 0.2854 in (6.75 to 7.25 mm)

Fuel pump
Output 75 litres/hr (16.5 gal/hr)
Actuating lever stroke (C, L and CL) 2.4 to 2.6 mm (0.0949 to 0.1024 in)
Actuating lever stroke (Sport) 2.4 to 2.9 mm (0.09 49 to 0.1142 in)
Delivery pressure at 4000 engine rpm 0.17 kgf/cm2 (2.55 Ibf/in2)
and fuel temp 30°C (86°F)

lgnition system
Distributor
Type and code Magneti Marelli S155HX
Automatic centrifugal advance 25° ± 2° at 4500 rpm
Condenser capacity (50 to 1000 Hz) 0.20 to 0.25 µF

Clutch
Lining outer diameter 181.5 mm (7.146 in)

Lining inner diameter 127.0 mm (5.0 in)

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3. Engine

1049 cc engine - general
1 This engine is of overhead camshaft design,
using shims for valve clearance adjustment. The
crankshaft is supported in five main bearings,
the centre one incorporating the thrust washers
which control crankshaft endfloat.
2 An auxiliary shaft, driven by the toothed
camshaft belt, is used to drive the distributor and
the fuel pump. 3 Most major engine components
can be removed while the engine is in the car,
but operations on the crankshaft, main bearings
and flywheel can only be carried out after the
engine has been removed.
4 Engine removal and subsequent dismantling
follows closely the information given for the
overhead valve engine in Chapter 1, but the
following sequence for complete engine
dismantling is recommended:
(a) Engine ancillaries (alternator, fuel pump, distributor)
(b) Timing belt cover
(c) Water pump
(d) Timing belt tensioner and belt
(e) Manifolds
(f) Cylinder head complete with camshaft
(g) Crankshaft pulley
(h) Auxiliary shaft sprocket
(i) Sump
(j) Oil pump and auxiliary shaft
(k) Connecting rods and pistons
(l) Flywheel and crankshaft oil seal carriers
(m) Crankshaft and main bearings

5 If the cylinder head is to be dismantled, before

withdrawing the camshaft, have a suitably divided
container ready so that the valve clearance
adjusting shims can be extracted and kept in strict
originally installed order together with their
appropriate valves, springs etc.
6 All engine parts must be thoroughly cleaned
and examined as explained in Chapter 1. Where
required, all defective parts should be renewed
before reassembly starts.
Crankshaft – refitting
7 Fit the main bearing shells to their seats in the
crankcase after making sure that both shells and
seats are spotlessly clean and dry (photos).
8 With a light smear of grease, fit the two half
thrust washers each side of the centre bearing
with the oil grooves in each washer facing away
from the bearing shell (photo).
9 Using clean engine oil lubricate the bearing
shells and crankshaft main bearing journals
(photo).
10 Carefully lower the crankshaft into its bearings
in the crankcase after making sure that it is the
right way round. Spin the shaft to distribute the o il
(photo).
11 Fit the clean and dry bearing shells to the main
bearing caps. Oil the bearing face and fit the
bearing caps to the crankcase. Make sure that
each cap is fitted to its own location by checking
the groove marks in the base, and that each cap
is the right way round. This is achieved when the
axial locating tags in each half bearing shell butt
on the same side (photos).



3.7A Thoroughly clean the bearing shells and seats
before
assembly 3.7B Note that central bearing shell has no oil gro ove but all
shell are axially located by an offset tag

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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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3.18 The valve depressions in the piston are adjece nt to
the cylinder head studs in the block 3.20 Torque tighten the big-end cap nuts


3.22A Firts fit outer rotor to the oil pump body… 3.22B …followed by the inner rotor



3.23 Measure the end clearance of the rotors with t he
pump face 3.24 Measure the outer rotor to body clearance…