AC"SIX" 2-Litre. Ace, Acedes, Aceca, Magna, Aero and other versions, built from 1919 to 19

Ace, Acedes, Aceca, Magna, Aero and other versions, built from 1919 to 1956 (data for 1927 Acedes). Built by: Autocarriers Ltd., then (from 1922) AC Cars Ltd., Britain. Engine: Six cylinders, in line, in five-bearing, wet-liner, cast-alloy block. Bore and stroke 65mm by 100mm, 1,991cc (2.56 x 3.94in, 121-5cu.in). Cast-iron cylinder head. Two over-head valves per cylinder, operated by single overhead camshaft. Single carburettor. Maxi-mum power about 40bhp. Transmission: AC plate clutch at rear of engine, cast-aluminium torque tube to gearbox, in unit with back axle. Three forward speeds, without synchromesh, ratios 4.5, 7.00 and 132 to 1. Alternative ratios on request. Right-hand gear- change. Overhead-worm-drive back axle. Chassis: Pressed-steel channel-section side members, with tubular cross members. Front axle suspended on forward-facing quarter-elliptic cantilever leaf springs. Quarter-elliptic leaf springs at rear. Friction-type dampers at front only. Snubbers above back axle. Four-wheel brakes, 12in by 14in drums all round. Several variations in coachwork — two/three seat tourer, coachbuilt saloon, or fabric saloon. Dimensions: Wheelbase 9ft 3in or 9ft 9in (282 or 297cm), tracks (front and rear) 3ft 9in (114cm). Overall length, from 13ft 9in (358cm) —depending on coachwork. Unladen weight, 23201b (1052kg). History: The AC 'Six' was not a single, long-lived model, but a progressively improved family of cars. Its engine, in particular, established a record in Great Britain, by being in active pro-duction from 1919 until 1963, when it was last used by AC in the Ace sports car. AC cars were first made in 1913, although there had been tricars before that, and the com-pany always made their products in Thames Ditton, on the south-western outskirts of London. Their first car was a four-cylinder two-seater (the engine being by Fivet, from France) and it had features like the gearbox in unit with the back axle, something which was to be an AC charac-teristic for so long. There was even an axle disc brake. The legendary "Six' was designed by John Weller during World War I, was announced in 1919, and went on sale in 1920. It was quite remarkably advanced by the standards of the day and still looked reasonably up-to-date when being sold in the 1960s. The aluminium-alloy block/crankcase combined with spigoted wet liners, was unusual, as was the fact that a cast-iron cylinder head was specified. Ex-Napier chief Selwyn Edge joined AC in 1921 and became Governing Director in 1922, whereupon the company's founders, John Weller and John Portwine walked out. Edge then changed the company's name to AC Cars Ltd., by which it is known today. Success in competition was thought necessary to prove the vehicle, and AC often competed for distance records at the nearby Brooklands track. The Hon. Victor Bruce won the Monte Carlo Rally in 1926 (the first win by a Briton). One production version of the car — the 16/40 'Montlhery' AC — could exceed 80mph at a time when most cars, including 3-litre Bentleys, were struggling just to approach that speed. The 'Six' put on weight later in the 1920s, as bodies became heavier and equipment became more complex. AC countered this by tuning up their splendid engine and for 1928 the Acedes was given 56bhp. Half-elliptic front springs and hydraulic brakes appeared before the end of the 1920s, by which time an AC saloon might weigh up to 2,7001b (1,224kg). When Edge retired in 1929 the company was placed in voluntary liquidation, but it was revived by the Hurlock brothers in 1931. They produced a new design, still relying heavily on the alloy "six', but with a new chassis, a Moss four-speed gearbox in unit with the engine and a central, remote-control gearshift. The first 'Ace', perhaps better known in its 1950s guise, appeared in 1935 and was a pretty and light little sports two-seater, ideal for rallies and trials. Acceleration from rest to 60mph in about 18 seconds was fast by any standard and the handling offered by the half-elliptic leaf springs all round was very sporting. Synchromesh gears, or the option of the British Wilson _pre-selector box, came in at about the same time. 80bhp was talked of from the 1,991cc engine, but this was almost certainly optimistic. At one stage, at the end of the 1930s, an Arnott supercharger could be ordered as an extra, and automatic chassis lubrication was standardised in 1937. After World War II, the existing designs were dropped, and replaced by a single new model, the 2-litre. This was a two-door saloon at first, but a more expensive drop-head convertible also became available.

The chassis, although all-new, retained a rigid front axle and half-elliptic springs all round. The company was by no means committed to independent springing at that time. Engine power was now up to a guaranteed 76bhp at 4,500rpm, but needed a triple SU carburettor installation to guarantee this. AC were always too busy with their other activities (which included making three-wheeler invalid cars under contract to the British Government) to up-date the 2-litre, which eventually went out of production in 1956.

Be/ow: The six-cylinder ACs had an enormously long and successful run, though only the engine was a constant feature. This was a 1925 tourer with disc wheels and the obligatory dickey seat of the 1920s. AC was guided by Selwyn Edge in the 1920s.