1930 Alfa Romeo 6C 1750

The Alfa Romeo 6C 1750 was produced from 1929 through 1933 but its origins trace to 1923 when Nicola Romeo hired engineer Vittorio Jano from rival Fiat to design a Grand Prix car. In less than a year, Jano had created the P2 whose success was immediate, claiming the first manufacturer's championship for Alfa Romeo in 1925. Jano's next task was to design a production chassis with a similar sporty persona to its P2 cousin. What emerged was the series of six-cylinder (6C) cars built in various specifications, beginning with the 6C 1500 of 1927 and culminating with the 6C 3000 of 1948. The former was introduced at the Milan Motor Show in 1925 and series production following two years later. Its 1,487cc, six-cylinder engine had single overhead camshafts and 5.75:1 compression in Normale configuration while the Sport, Super Sport, Super Sport Compressore, and Super Sport Testa Fissa variants used dual overhead camshafts and had higher engine output. With a single carburetor, the Normale developed 44 horsepower at 4,200 RPM. The Sport also used a single carburetor but developed 54 bhp at 4,500 RPM. The Super Sport Testa Fissa was the ultimate specification, employing a single carburetor, a supercharger, 5.25:1 compression, and offered 84 bhp at 5,000 RPM. The Normale had the cylinder block and head in one unit whereas the twin cam was usually fitted with a detachable head. Some of the Super Sports, including the Mille Miglia Speciale, had the block and head in one unit called 'Testa Fissa.' Nearly all of the 6C 1500s had five main bearings except for a few of the later testa fissa engines which had eight. The cylinder head featured Jano's unique valve adjusting arrangement using a special tool. The overhead camshafts were motivated via a vertical shaft at the rear of the block. The dynamo and water pump were driven off the rear of the crankshaft by a set of cross-shaft gears.

Four seater coachwork received a 114.2-inch wheelbase, the 6-seater and Normale had a 122-inch platform, and the Sport and Super Sport rested on a 115-inch platform. Steering was a worm and wheel arrangement and the brakes were rod operated. Conventional semi-elliptic springs were located at all four corners plus the rear added friction shock absorbers.

The Tipo 6C 1750 received a derivative of the 1500's all-alloy six-cylinder engine, enlarged to 1,752cc. The bore and stroke of the 1,487cc unit measured 62mm and 82mm respectively, while the 1,750cc unit had a 65mm bore and 88mm stroke. Built in single-cam Turismo and twin-cam Sport (later renamed Gran Turismo) variants, the 6C 1750 continued the 1500s formula of lightweight coachwork with robust performance. The chassis, too, was lightweight and its nimble nature was further enhanced by its low stance, with the semi-elliptical springs passing through the front axle. The refined 6C 1750 would claim victory over much larger and more powerful machinery.

The chassis length continued to measure 115-inch (2.92m) or 122-inch (3.10m) for the Turismo, Sport and Gran Turismo while the Super Sport (SS) was 108.1-inch (2.745m) with an engine that featured both naturally aspirated and supercharged versions. The Super Sport had the same rearward engine location of the 6C1500 Super Sport. The unblown SS engine produced 64 horsepower while the finned alloy Roots-type supercharged version offered 85 bhp.

The Super Sport name was updated to Gran Sport in 1930 and gained a sloping radiator that gave the car a more rakish appearance and functionally increased the surface area of the radiator for improved cooling.

The bodies for the 6C 1750 were created primarily by Zagato and Touring Superleggera. Three examples were built with James Young bodywork, and others were clothed by Figoni, Farina, Brianza, Castagna, and others.

The 6C won every major racing event it contested in 1929, and its sporting career extended far beyond its production, with numerous victories, including 1-2-3 finishes in the Mille Miglia, and top results at the Tourist Trophy, Targa Florio, and Spa 24 Hours in 1930. It won the Mille Miglia in both 1929 and 1930 and won its class at LeMans in 1930 and 1932. Legendary drivers responsible for these successes include Nuvolari, Marinoni, Campari and Varzi.

Approximately 1,058 examples of the Alfa Rome 6C 1500 were built. Production of the 6C 1750 was higher, with 2,635 units built in four series from 1929 to 1933. Most of the 6C 1750 were built as single-cam Turismo versions (the replacement for the Normale) on the long 122-inch chassis. A few of these cars were classified as Sport models with a 114-inch chassis and the twin-cam engine. Most of these cars were clothed with Alfa saloon coachwork and renamed Gran Turismo.

by Daniel Vaughan | Sep 2022