Today most Alfa aficionados keenly seek out the GTV from the early 1970’s, however the more humble sedan has become a very rare sight on Australian roads, and may prove to be a sound investment for the astute collector.
Among the different automobile Firms who chose the 47th Brussels Show to raise the curtain on their latest models, Alfa Romeo will probably be remembered for having presented not just one new model, the 1750, but also the two versions derived from it.
This of course had always been an old tradition of the Milan builder - to place various derivatives, usually sporty in character, alongside a basic model. But everyone was surprised, with the 1750, to be suddenly confronted with a triple birth.
This unexpected proliferation was, however, perfectly justified: the Alfa Romeo 1750 really represented a development of the Giulia 1600, from which it inherited among other things all the mechanisms, and it was therefore logical, at least from the economic and productive point of view, to base the 1750 range upon the ‘ripening' of the 1600.
And of course this is why you will find the wonderful 1750 engine under the bonnet of a sedan remodelled by Bertone, and at the same time under that of a GT Coupe and a Spider Veloce.
Since the 1750 engine in fact had an effective piston displacement of 1800 cc., it is not always obvious why the 1750 Alfa’s were given a designation which did not fully do them justice.
But those who have studied or know of the 'Belle Epoque', or who knew the ‘symbols' which contributed to their fascination, will recall that during the 1920’s there was already a 1750 in the Alfa Romeo programme.
Exemplary among the most exciting automobile fauna of the epoch, the Alfa Romeo 1750 was also a milestone in the Milanese firm's history. In fact, besides being invincible in the agonistic field, it allowed Alfa to realise, for the first time, an entire range of touring and grand touring cars derived from a model designed first of all for competition.
At the same time the firm of Portello also discovered where its true strength lay, for with the 1750 production reached an industrially important volume for the first time: between 1929 and 1933 nearly 2500 iterations being built, that being more than double the production achieved during the previous four years with the 1500 model, from which the 1750 was derived.
It is also interesting to remember which point the technical evolution of the era had reached. The Alfa Romeo 1750 then had a 6 cylinder engine in cast iron. On the ‘Sport' and ‘Gran Turismo' models the head had twin camshafts and the effective output was 55 HP at 4400 rpm.; the sedan carried four passengers, had a dry weight of 1150 kg and reached 125 km/h.
By contrast, the 1967 1750 Sedan had an engine built completely of light alloy, which produced 132 HP (SAE) with two cylinders fewer and with corresponding rpm only 1100 higher. The sedan weighed about 100 kg less and carried five people in far greater comfort to speeds in excess of 170 km/h.
On the other hand when, in 1931, the output of the 1750 engine was brought to 80 HP, with the use of a supercharger, the sedan became so bulky (1360 kg dry weight, wheelbase lengthened from 292 to 316 cm, etc.) that its maximum speed only increased 10 km/h! And if one wanted 'to reach 145 km/h it was then necessary to turn to the uncomfortable competition ' Super Sport' spider, which was very light (840 kg!), and whose fixed head engine (and supercharger) produced 95 HP at 4800 rpm.
The design of the Alfa Romeo 1750 came about as the result of market research involving about 20,000 of the firm's customers, and according to which the two most requested improvements (on the basis of the success achieved by the Giulia) concerned habitability and comfort understood as class and function ability of interior furnishing (sound proofing, finish, trimming, etc.).
A New Design On The Pattern Of Giulia
As stated earlier, it was decided to develop the new design on the pattern of the Giulia. This was not so much for economic convenience the cost of tooling for the 1750 amounted more or less to that of a car designed completely from scratch - as for the technical opportunity, since for the effectiveness of certain basic characteristics, (structural and otherwise) a twinning of the Giulia and the new 1750 was not only feasible, but undoubtedly desirable. In this way the setting up stage would also be simplified, a stage which, as Eng. Satta rightly claimed, was rather like an equation in which every new solution represented an unknown quantity.
Thus, before being born, the Alfa Romeo 1750 had been defined with enough accuracy to constitute a ‘predetermined theme’ whose challenging dress was entrusted to the Bertone Carrozzeria. The difficult task of the Turin coachbuilder can also be estimated by the fact that the new 1750 had still, in respect to the Giulia, the 'family' lines more accentuated just where the stylist would perhaps have liked to soften them.
This is precisely the case with the passenger compartment which, apart from a slight lengthening due to the increased wheelbase (257 cm instead of the Giulia's 251 cm), still retained the unmistakable 'hull '. Besides an obvious architectural resemblance, the new 1750 shared several details with the Giulia, such as, for example, the design of the windscreen which had been kept unchanged for its qualities of visibility united with aerodynamic properties of the highest degree.
Bertone Styling Smooths The Edges
But Bertone's pencil reclaims its rights in the end sections and in the joins between the various surfaces whose essentially fluid, even if classsic, treatment canceled out the characteristic surface ridges which marked the unusual personality of the Giulia. Among the details worth noting are the dihedral sections of the side, the air intake which integrates (widthways) the entire front section, the vertical cut of the tail, confirming the validity of an aerodynamic principle already applied successfully by Alfa Romeo.
As a whole the line of the new 1750 was well-balanced and pleasing, and a badge on the side reminds one that its author is Nuccio Bertone. With this recognition Alfa Romeo confirmed the valuable contribution derived from the outside cooperation of a great coachbuilder.
Despite its more 'important' look the Alfa Romeo 1750 sedan had no more bulk than the Giulia. The height (143 cm) was unchanged in spite of the smaller wheels (14" rims instead of 15"), the width was only half a centimetre more (156.5) while the length (439) was 25 cm more. The lengthening of the car was moderate, and thus the aerodynamic advantages gained from it were also small, but sufficient to offset the equally slight increase in the coefficient of penetration, resulting from the larger front end.
The car's increased length had obviously influenced the front and rear overhangs, which were 113 and 65 cm longer respectively, lengthening correspondingly the crushable parts of the body. The 1750 bodywork had other improvements too, with respect to the Giulia, whose shell had already aroused wide approval for its accurate design from the passenger safety viewpoint. The body has been strengthened by increasing the average gauge of the metal sheet by 0.2 mm, at the same time increasing the un-crushability of the passenger compartment and the gradualness of boot and bonnet resistance to deformation.
Rear roof pillars were now boxed and integral with the wheel arch. Other elements had been re-modelled, such as the quadrilateral front end which also supporteed the hinges of the bonnet lid. The walls between engine, passenger and luggage compartments, plus the internal panels of the doors are lightened to the minimum; the framework of the two lids is also considerably more robust.
In spite of the structural oversize (and the lengthened wheelbase), the bare shell of the 1750 sedan (including bonnet and boot lids and doors) only weighed 13% more (295 kg) than the Giulia's. The interior of the Alfa Romeo 1750 was completely new. Above all, the extra six centimetres of the wheelbase had been used to the advantage of the rear passengers, the usable space of which, in the longitudinal sense was increased from 690 to 770 mm.
A lot of care had gone into the interior decoration. The rear seats were separated by an armrest containing a stowage box, and the arm could be replaced by a 'cushion' to carry a fifth passenger. The front seats were also separate (and adjustable) and their padding consisted of a new, rather firm, synthetic material which by rapidly responding to the passengers' movements, increased riding comfort.
The facia was new too, and both the structure (framework in steel sheet and synthetic material) and the external shape had been studied with particular attention to passenger safety, and were in keeping with the American deformability regulations of the day. Thus the 'bare' dashboard: just two circular dials, were placed in the driver's line of vision, while the other instruments (all circular) were placed on a central shelf together with the gear lever and controls.
The roof rear pillars contained ducting for expelling stale air from the passenger compartment under depression. The cockpit was well sound-proofed, with floor and walls covered in a sound deadening material which was a rather thick 20 mm in some places. To also minimise NVH, the Alfa engineers modified the gearbox support and clutch housing, these being widely regarded in previous Alfa models as an annoying source of noise at certain engine speeds. The clutch was hydraulically controlled.
Among other details intended to eliminate vibrations and noise, the engineers used a synthetic bonding compound, which although it hardened, managed to retain a degree of elasticity, after a heat polymerisation process. Despite the rear end lengthening the boot retained a capacity of about 480 cu. dm. In comparison with the Giulia Super, the Kerb weight had risen from 1040 to 1110 kg.
Given the level of detail and mechanical underpinnings, the 1750 sedan really was a great car. However given that it will never compete with the gorgeous looks of the GTV, it remains a little less collectable. That’s a shame, because in every other way, the 1750 sedan was a worthy equal.