AC Ace bristol – one of the 1950’s greats.
The AC Ace-Bristol: Thames Ditton’s Finest Hour
The Ace-Bristol is often merely described as the forerunner of the Cobra, which is a little unfair as it was an outstanding sportscar in its own right, and in many ways a better-balanced one. It came from a small Surrey firm that was short of money, from a privateer who pushed it forward, and from an engine that began in pre-war Munich. Those are unusual beginnings for one of the finest British sports cars of the 1950s.
A borrowed chassis, a borrowed style
AC Cars did not design the Ace from scratch. By the early 1950s the company’s range was ageing, and it had neither the money nor the staff for a clean-sheet sports car. The answer came from John Tojeiro, whose twin-tube ladder-frame sports-racers were winning regularly in English club racing. His simple chassis used transverse leaf springs at each end to give fully independent suspension, which was advanced for a small British maker at the time.
The body followed a similar logic. Tojeiro’s car for Cliff Davis wore a barchetta style body modelled along the lines of the Touring-bodied Ferrari 166 MM. AC refined the lines rather than reinventing them, and the car it showed at Earls Court in 1953 looked leaner and more elegant than anything else in its class. AC bought the rights to the design from John Tojeiro for the bargain price of £500!
The engine problem
If the Ace had a weakness it was under the bonnet. AC’s own two-litre six was a John Weller design that first ran in 1919, so it was already more than thirty years old. It was smooth and it looked handsome, but with under 100 bhp it was obvious the chassis had much more to give.
The solution came from a customer. Ken Rudd, a Worthing garage owner and racing driver, fitted a Bristol engine to his own Ace, and the results made the case plainly as he won the 1956 Autosport production sportscar championship. AC began offering the Bristol unit in 1956, and the Ace-Bristol was born.
A German heart by way of Filton
The Bristol engine had an unusual history. It was a development of the pre-war BMW 328 six cylinder, a design which the Bristol Aeroplane Company obtained the rights to after the war as part of reparations and developed in its own works. Its most distinctive feature is the cylinder head which employs hemispherical combustion chambers, but avoids overhead camshafts by using a single cam mounted in the block and a system of cross-pushrods to work the exhaust valves. It is intricate, even eccentric, but it works well.
In 100D2 form, with three Solex downdraught carburettors, the Bristol engine gave around 125 bhp. That made the Ace a genuine 115 mph car, with a chassis and brakes capable of exploiting the power fully, especially when front disc brakes were offered as an option from 1957.
Proven at Le Mans
The Ace-Bristol earned its reputation in competition. Ken Rudd and Peter Bolton took an Ace-Bristol to Le Mans in 1957 and finished tenth overall and second in class. Two years later Ted Whiteaway and John Turner brought their privately entered car home seventh overall and first in the two-litre GT class. It was a strong result for an amateur entry against larger manufacturers.
In the United States the car did at least as well. It was a regular front-runner in SCCA racing taking the Class E Championship in 1957, ‘58 and ‘59, and that record did a great deal to establish the AC name there. It is the main reason Carroll Shelby took an interest in the car later on.
An ending forced from outside
The Ace-Bristol did not fade away through lack of demand. It ended because its engine supply stopped. Bristol Cars moved to Chrysler V8 power, the six-cylinder engine went out of production in 1961, and AC had to find a replacement. The Ford Zephyr-based 2.6-litre unit, developed again by Ken Rudd, filled the gap for a short time but within a year Carroll Shelby had arrived on the scene, a V8 had gone into the chassis and the Cobra followed.
Around 460 Ace-Bristols were built. Today the model is valued for exactly what makes it worth writing about: its balance, its competition record and its unusual origins. Many drivers think the Bristol-engined Ace is the most complete expression of the design, with the chassis and engine better matched than they ever were in the Cobra.
