Carburation & Fuel System

General Arrangements for Different Models

The following schemes show some of the general arrangements of the fuel systems used on Aurelia models. There were many variations in fuel tank design, fuel gauges, position of the fuel reserve tap, fuel pump type, carburettors, air cleaner type & number & design of the exhaust system. There were of course modifications made to cars in the after-market with Nardi conversions being amongst the most well-known (Performance Modifications).

Parts List for Tav.10 above & Tav. 10bis below

Tav. 10 for Cars up to B10-2935, B50-1427, B51-1073 & B21-1038

Fuel System for B20 Series 4 Cars.

Fuel Tanks & Level Sender Units & Dashboard Gauges

For information on the fuel gauges see Dashboard, Control & Instruments

The fuel tanks, fuel lines, reserve taps & fuel gauges differed considerably from model to model. The B20 Series 3 was distinctive with its fuel filler placed centrally at the lip of the boot space, whereas in most other models it was place to the left.

The fuel gauge in the B20 Series 4 with Jaeger instruments was in the speedo fitting & was special in using a potentiometer-type tank sender unit with two electrical wires.

Petrol smells, a common complaint on older cars is usually the result of the perishing of the rubber overflow/sloshing pipe

Tav. 11 Series I – Fuel Tank for B10 etc.

Tav. 11 Series II – Fuel Tank for B12

The following table gives details of the fuel tanks & sender units, from which it can be seen that there were 4 types of tank fitted to Series I cars. 1st Series B20s had the B10 later tank, 2nd Series had another tank & 3rd Series had the distinctive centre-filling tank.

For Series 2 there were 3 types for the B12, including an export version, & 2 types for the B20 Series 4, 5 & 6 including an export version & 6 types for the B24 including 3 export versions – a total of 15 types of tank!

Table of Fuel Tanks & Level Sender Units

Note: Not absolutely sure about this for the RHD B24 cars as parts book unclear.

The fuel level senders also changed but only 2 types were fitted to Series I cars firstly one made by Metron & then for the B20 Series 2 & 3 one made by Borletti. For Series II cars Borletti continued to supply for the B12 & another type for the early B20 Series 4 with Veglia main dashboard instruments. From the late 4th Series B20 (B20-3421 on) the senders & dashboard instrumentation was made by Jaeger & 3 types were fitted; the B24s seem to account for another 4 types with Borletti for the 4th Series B24 RHD cars & Jaeger for the rest – a total of 11 types!

Mechanical Fuel Pumps

Five types of mechanical fuel pumps were fitted (see table below) made by ALIT or FISPA.

Tipo ALIT Fuel Pump (Tav. 12 SI) Fitted to B10s etc.

Tipo FISPA Fuel Pump (Tav. 12bis SI) Fitted to later Series I & up to early SII cars

Fuel Pumps fitted to Aurelia Cars

Pumps #3 & #4 Tipo ALIT Excelsior differ in minor respects as far as I can see. In the Tav. 13 SII below parts #1, #16 & #22 are the main ones.

On older cars, or any car with a fuel tank of unknown condition, regular cleaning of all fuel line filters is essential. Fuel pump filters #7 in the ALIT Excelsior pump above & #17 in the FISPA pump below are easily accessible at the top of the pumps & should be cleaned with petrol or paraffin.

Tipo FISPA-mod.SUP.60 Fuel Pump (Tav. 13bis SII)

Replacement Parts (rather dated information):

Fitting an Electrical Pump

Many cars have had electrical pumps placed either instead of or in tandem with the original pump. SU electric pumps have been successfully been fitted to many Aurelias. One is driven to this on a car that is not used every day due to the drainage/evaporation of fuel from the carburettor float chambers & supply lines & the subsequent strain on the battery when trying to start the car. The effort to prime the carburettor can flatten the battery with frustrating results. This is especially the case with cold starting in cold weather.

The pump is best connected in the tank to pump pipe before reaching the mechanical pump. If the electric pump is connected through the ignition fuse it then operates as soon as the ignition is on & primes the carburettor immediately. A good place to fix the pump is behind the grille in the cool air flow under the horns.

Fuel & Air Filters

Fuel Filtration

Filters for the fuel supply are fitted in the base of the fuel tank, in the top of the mechanical fuel pump, on some models as a separated glass-bowled filter (see below) & also in the carburettor inlet unions.

See the relevant exploded diagrams for these parts. These filters should all be regularly cleaned or replace to ensure proper running of the vehicle. Cars with suspect fuel tanks & those not fitted with bowl-type filters will benefit from adding a bowl filter or the modern in-line polythene-cased disposable paper filters.

Tipo FISPA 2035/FC Fuel Filter (Tav. 12 SII)

The above fuel filter was fitted as standard to the B12 & B20 from no. 2952 with ALIT Excelsior fuel pumps. On these B20s intended for export a pressure-regulating valve was fitted. Those later B12s, B20s & all B24s fitted with the FISPA fuel pump thus do not seem to have been fitted with a fuel filter as standard.

Air Filtration

Seven different air filters were fitted as standard & numerous after-market & competition/sporting products were used to improve the ‘breathing’ of the cars. The standard air filter housings & filters are described below.

For some coloured illustrations of air filters see below.

B10 & B12 Air filters

Tipo B10-0768R Air Filter & Inlet Tract (Tav. 14 SI)

Tipo B12-0768R Air Filter & Inlet Tract (Tav. 15 SI)

Air Filters as seen on Extant Cars

Air filters as fitted to car B53-1016 probably as Nardi conversion

Air Filter B20-0768BR as fitted to B20 3^rd to 6^th Series cars - On Car B20-3157 restored paintwork, missing original label

Nardi air filter housing for twin carburettor conversion as fitted to B20-1819

Air filter 1702393 ex-B24-0768R fitted to car B24-1008

Air Filter B20-0768BR as fitted to B20 3^rd to 6^th Series cars - On car B20-3701 unrestored with original aluminium supplier’s label.

Carburettors

The following types were fitted as original equipment:

Data on Carburettors

The material to hand consists of technical data sheets from Solex & Weber, extracts from a substantial Lancia C. technical AST ‘Sketch’ no. 1123 which covered a wide range of carburettors up to 1966, some other Lancia AST Sketches & the Aurelia Spare Parts Catalogues.

The information below has been put in the chronological order of the carburettors in the above table.

Weber Carburettors –- Notes

The SOLEX C.30-AAI Carburettor

The SOLEX C.35-AAI Carburettor

Special Characteristics

Single Source of Air – The air required for float chamber ventilation, slow running & mixture emulsion, is all drawn from the carburettor main air intake & thus, is compelled to pass through the air cleaner.



The arrangement has the two-fold advantage of eliminating impurities & of rendering fuel consumption independent of air cleaner conditions of cleanliness, while keeping mixture richness constant.

Starter – The starter ensures starting from cold, slow running from cold & driving away. It is used until the engine has reached its normal running temperature.

The starting mixture strength changes with the position of the dashboard control, the weakening of the mixtures is gradually obtained by progressively releasing the dashboard control.

Fully out (starting position), the mixture is very rich, & allows starting when the engine is cold.

Half way in this intermediate position is used when the engine is just warm, either after having run in the previous position, or when the engine has not become quite cold after stopping.

Accelerating Pump – The accelerating pump is of the standard type installed on Solex carburettors. The special feature of the pump on this carburettor is represented by the control, which is so designed, that the output fuel of pumping strokes, besides being adjustable in quantity, may also be injected during the rotation of the primary throttle alone, secondary throttle alone, or of both throttles simultaneously.

Connection for suction Ignition Advance – On the engines fitted with depression-operated ignition timing, connect the depression pipe to the tube provided on the throttle body of the carburettor

The following improvements have recently been brought in the SOLEX 35 PAAI carburettor of the Flaminia engine & apply to all cars in circulation:

1. Replacement of the starter jet (230) with another of (180)
2. Correction of the injector stream aim as shown in fig. 1 & fig. 2 above so that the stream of fuel hits the upper part of the choke tube instead of falling inside.

The following exploded parts diagram is taken from the Flaminia Spare Parts Catalogue by Lancia C. & is a different of, & differently numbered figure from that of SOLEX on page 01.7/19 above.

The WEBER 32 DR 7SP Carburettor

The WEBER 40 DCF/DCL/DCZ 5 Carburettors

The Weber 40 DCF/DCL/DCZ 5 for the Aurelia B22, B24 & B20 from B20-2232 (Tav. 13bis SI & Tav. 14 SII)

Note: The jet sizes have been taken from various Aurelia Instruction Books. The DCF information applied to the B20 Series 3; the DCZ was for a Series 4; the DCL was for Series 5 & 6. All numbers are in mm