'Of them all, the Ace was the truest sports car: it could be used for daily commuting or for high-speed long-distance touring, but it could also be driven to a race meeting, campaigned with distinction, and driven home again - even if that race was the Le Mans 24 Hours.' - AC Heritage, Simon Taylor & Peter Burn.
The success of Cliff Davis's Tojeiro sports racer prompted AC Cars to put the design into production in 1954 as the Ace. The Davis car's pretty Ferrari 166-inspired barchetta bodywork was retained, as was John Tojeiro's twin-tube ladder frame chassis and Cooper-influenced all-independent suspension, but the power unit was AC's own venerable, 2.0-litre, long-stroke six. This overhead-camshaft engine originated in 1919 and with a modest 80bhp (later 100bhp) on tap, endowed the Ace with respectable, if not outstanding, performance.
In 1955 AC added a hardtop version - the fastback-styled Aceca - and both models became available from '56 with the more-powerful (up to 130bhp) Bristol six-cylinder engine. The l,971cc Bristol six was based on that of the pre-war BMW 328, which featured an ingenious cylinder head, designed by Rudolf Schleicher, incorporating hemispherical combustion chambers and inclined valves without recourse to overhead, or twin, camshafts. Instead, the earlier BMW Type 319 engine's single block-mounted camshaft and pushrod valve actuation were retained, thus avoiding an expensive redesign. Two rocker shafts were employed, one situated above each bank of valves, giving the engine an external appearance almost indistinguishable from that of a twin-overhead-cam design. Downdraft inlet ports contributed to the motor's deep breathing, and its tune-ability made it a popular choice for British racing car constructors, most notably Cooper, during the 1950s. Externally, Bristol's clone of the BMW motor differed little from the German original, the most obvious difference being the adoption of SU, rather than Solex, carburettors part way through production. The most significant changes made by the Bristol designers were metallurgical; their utilisation of the highest quality materials contributing to greatly increased engine life.
The combination of a fine-handling chassis and a decent power-to-weight ratio - in Bristol-engined form the car could touch 120mph - helped the Ace to numerous successes in production sports car racing, arguably its finest achievement being a first-in-class and seventh overall finish at Le Mans in 1959. Indeed, its basic soundness and versatility were reflected in the fact that relatively few major changes were found necessary when the Ace was endowed with Ford V8 power to create the legendary Cobra.
Originally a left-hand drive model exported to the USA, this Bristol-engined Ace (now right-hand drive) was first owned by one R B Hayward, passing in June 1994 to previous owner Keith Roach of historic-car coachbuilders Roach Manufacturing & Engineering. The current owner acquired the Ace on 9th July 2010. Its first owner had swapped the original engine for the more powerful 100D2 unit currently fitted, and it was decided to undertake a complete rebuild while at the same time increasing the maximum power output. The brief was to end up with a 150bhp road/track car (easily up-rated further to racing specification) that would still be capable of long-distance Continental touring if required. Works undertaken included overhauling and porting the cylinder head and fitting new Cosworth pistons/rings, 'high-torque' crankshaft and damper, long connecting rods and a lightweight flywheel. In addition, the oil pump and starter motor were renewed, the overdrive gearbox rebuilt with a close-ratio cluster, and an aluminium radiator and Kenlowe electric fan installed. All the minor items associated with such a rebuild: valves, guides, studs, nuts, bolts, chains, bearings, seals, gaskets, etc were replaced with new top quality items. Other noteworthy features include a gel battery and five new 72-spoke 15" wire wheels. Only some 1,000 miles have been covered since the rebuild's completion last year and the Ace is described as in generally excellent condition. Finished in silver with Burgundy leather interior, the car is offered with restoration invoices, current MoT/tax and Swansea V5C registration document.