THE story of the AC Ace really began in 1919 when John Weller produced his first AC “light six” engine. This was a wet linered six cylinder unit of 1991 cc. It had a chain driven overhead camshaft, and was mainly of aluminium construction. It was essentially this engine that, for nearly 40 years, powered the cars that came out of AC’s Thames-Dillon factory, from 1919 until 1956. The AC engine obviously underwent considerable modification during this time, so that the power was stepped up from an original 40 bhp, to 85 bhp when it was first used in the AC Ace that is the subject of this article.
An engine, however, is not of much use without a chassis, and the other half of the story begins with a chap named John Tojeiro, who had made quite a name for himself in post-war racing circles. At his workshop in Buntingford, in Herefordshire, he built very competitive sports car chassis that were powered by various engines including MG, Lea-Francis, Wolseley and JAP. The most notable for its success, however, was Cliff Davis’ Bristol engined car, raced throughout 1953 at British second level meetings. It was Ernie Bailey, who ran the Bunt
ingford coachworks where the Buckland four-seater sports tourer was built for AC, who made the connection that brought the AC engine and the Tojeiro chassis together. He was well aware of the Tojeiro product when he heard that AC were looking for a chassis. He arranged for Vin Davison’s Lea-Francis engined Tojeiro to be demonstrated to AC chairman Charles Hurlock. Mr Hurlock was hooked and took the chassis on as a prototype that would revive the old AC title ‘Ace’, first used in 1933, once the six cylinder AC engine had been installed.
The chassis, which remained the same as that on Cliff Davis’ car, was very simple in its layout. It consisted of two parallel steel tubes of 3in diameter running from front to back. These were cross braced, also by 3in tubing, almost exactly half way down the length of the car. Fabricated box sections supporting the suspension and drive assembly formed the cross-bracing at either end. The suspension at front and rear consisted of tubular wishbones and transverse leaf springs. Inclined telescopic spring dampers were fitted all round. The whole assembly at the front was inclined slightly
backwards to provide castor angle. It was therefore the first British post-war sports car with all round independent suspension.
The engine came with triple SU carburettors, and a pair of three branch exhaust manifolds, and was mated to the Moss four-speed gearbox via a Borg and Beck single-plate dry clutch. Power was transferred to the wheels through a chassis mounted ENV hypoid-bevel final drive unit. Girling hydraulic brakes in Wellworthy Al-Fin llin drums were fitted front and back. Dunlop knock-off wire-wheels carried 5.50in — 16in tyres. The aluminium two-seater body, basically similar to that of Davis’ car, was undeniably beautiful. The car looked purposeful but refined, and so it was. The AC Ace happily blended a proven race track ability with the standards of beauty, comfort and refinement required of a quality road going sports car. It was announced as an eve of the show surprise at the 1953 Earls Court Motor Show. Although at £1,297,7s 6d (including purchase tax) it wasn’t cheap, it did represent good value for money, especially when compared to the £2000 plus price of the Aston Martin DB 2-4 or Bristol 404. And, unlike any other British sports car at the show, it did boast all-round independent suspension. This was probably one of the main reasons behind the universal appraisal of the car
after its launch: that which was most singled out was the car’s outstanding road-holding ability. “Cornering is a sheer joy for there is a worrying degree neither of over nor understeer. The car shows no sign of front-end breakaway, even at elevated speed, and the tail looks after itself in the most satisfying manner. It is a car which will put up very high cross-country average speeds without any undue effort on the part of the driver; in short a sports car which handles as it should.” John Bolster wrote that it was “quiet, comfortable and exceptionally refined, with an excellence of roadholding and suspension that one rarely meets outside the racing sphere.” And The Motor said in 1954 that it showed “quicker acceleration from rest through the gears to 80 mph than other post war cars elf under three litres which we have tested.” The Ace had a top speed of 104 mph and covered the standing quarter mile in 17.9 seconds. But the performance and handling were not the only good things about the Ace. The aluminium body was beautifully made over a frame of steel tubes. The leather covered bucket seats gave excellent support, and there was a considerable choice of driving position. The hood, which was easy to erect and fold, gave excellent weather protection, and did not flap at high speeds. The boot provided a comparatively generous amount of luggage
room. In short it was a well thought out and high quality sports car. The first modification came to this initially good design at the 1954 Earls Court Motor Show, when AC exhibited its prototype fixed-head coupe, the Aceca. It was one of the most beautiful GT coupe
cars of the time. The basis of the aluminium body was a framework of steel tubes, as in the Ace, but with additional tubing to support the roof and tail of the car. The curvature of the Ace was slightly ironed out on the Aceca, especially along the wings from front to back. The doors were lengthened with the lower half slightly squared off. The tail of the car was altered so that the curve of the rear wing was given a sharper angle with the brake lights finishing the line. The roof sloped down to a fast back tail that was narrower and again less curvaceous than that of the Ace. The overall effect was very pleasing, and the modifications apt in that the Aceca was given a more graceful and sophisticated air than its sister. Less significant modifications were the adoption of a bishop cam type steering gear, and the mounting of the final drive unit on rubber, so that noise was reduced. Not surprisingly the performance of the Aceca was altered so that acceleration was reduced, because of extra weight, and top speed was increased, because of improved aerodynamics. The most significant change came in 1956 when the AC engine was replaced by the two litre Bristol unit that had already proved itself at Le Mans and in British sports car racing. The Bristol engine made the AC more potent since it turned out 120 bhp at 5750 rpm. But the peak power came at 1250 rpm more than the AC engine, and so one had to work the gearbox a little more in order to make full use of this gain. This was made slightly easier by the fact that the Bristol engine came with its own close ratio gearbox, and the whole assembly was some 25 lb lighter than the AC engine and Moss gearbox. Performance was certainly improved and the car now had a top speed of about 115 mph for the drophead and some 125 mph for the coupe, and covered the standing
quarter mile in 16 and 16.6 seconds respectively. As well as improving the performance on the road, the Bristol engine made the AC very competitive in sports car racing. The final change to the Ace and Aceca came in 1961. Bristol engines were in short supply, and from this point on were reserved for the AC Greyhound. Through an arrangement with K N Rudd Ltd of Worthing, Ace and Aceca models were fitted with modified Ford Zephyr engines. The standard units produced 90 bhp at 4700 rpm, but most owners preferred to have a tuned engine fitted. These were available in five stages of tune varying in price from £75 to £225, and in power output from 120 bhp to 170 bhp. In August 1961 MOTOR SPORT tested an Ace fitted with a 150 bhp engine and recorded a top speed of 124 mph, and a standing quarter mile of 16.8 seconds. So unless in the racing stages of tune the Ford engine did not significantly alter the performance from that given by the Bristol engine, although it probably meant more
power in the lower rev range. The most important change was that the Ford engine was cheaper to overhaul, or replace, and spares were so much more readily available. Slight body modifications were a smaller air intake at the front, and slightly flared wheel arches. Production continued until 1963 when AC turned its attentions to the commercially successful, but much less beautiful, AC Cobra.
We were fortunate enough to be offered a ride in one of the earliest and probably most original of the AC Aces. This AC-engined Ace was the seventh built and is now in the hands of its third owner. It was first owned by lady racing driver Betty Haig, who sold it to buy a Bristol-engined version with which she hoped to compete at Le Mans. The car then remained in the hands of one person until very recently and it has an original 24,000 miles on the clock. In fact it spent about 17 years on blocks during which time the engine was turned over once a month. Even so a considerable amount of work was needed to be done on the car before it was road worthy, mainly on the mechanics and suspension, which would have suffered by being kept stationary. However the originality of the car has been preserved and it is nice to see that, despite all the work done, the car has not been unnecessarily larted up’. The interior has a lived-in look to it, with nicely worn green leather upholstery, which would have looked splendid with what was probably the original olive green paintwork. The car is now white and was
painted by the second owner. It still has its first hood, tonneau cover, starting handle and jack all stowed away in the surprisingly spacious boot.
With the ignition turned on one could hear the familiar ticking of the SU pump feeding fuel to the three SU carburettors. The engine fired up encouragingly quickly and had a characteristically smooth straight six beat. As we pulled away it was immediately apparent that despite being almost forty years old, this car was no slouch, and would easily keep up with modern traffic. Even more significantly we were being powered by an engine that was essentially 71 years old. Plus ca change . . .
Clapham Common at midday is not the best place to explore the limits of a car’s performance and road-holding, unless it’s electric and is used for delivering milk. Things were made worse by the fact that I spent the majority of my tour trying to master the gearbox which my host politely suggested needed adjustment. Since it was a very slow change, and down changing benefitted from double de-clutching, I preferred to believe him, especially when considering the fact that contemporary road tests praised the quickness of the gearbox. Yet even at the relatively low speeds obtainable around Clapham Common one could begin to appreciate the precise and delicate steering, and the wonderful handling of the car that made it so distinctive when it was first produced.
The car could be driven with absolute precision in a way that bears out a contemporary remark in Autocar “One looks into a corner and almost simultaneously arrives at its end. The driver is left with the impression of having leaned over a little rather than of having turned the wheel.” The brakes inspired absolute confidence and the engine pulled readily from 1500 rpm. When wound up the car really did begin to accelerate quite sharply and I’m sure that the Bristol engine would make the Ace a quick sports car even in comparison with some of today’s machines. Another striking feature was
the driving position which was notably sensible and very comfortable. The steering wheel was the correct distance from the body, the gearstick fell easily to hand, and the pedals were a sensible distance beyond the steering wheel and dashboard. It was a shame not to be able to give the Ace some real exercise down a twisty and uncrowded country road, for which it is best designed. Nevertheless it was exciting to sit in and drive one, and to get a taste of this marvellous Fifties sports car. MOTOR SPORT is grateful to the owner at Paradise Garage for generously allowing us to drive the car. CSR-W
Continental Notes, August 1957
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