I would like very much to have included the 40/260 hp 9.7-litre Hatton-McEvoy in the Forgotten Makes series, but something which never existed can hardly be forgotten, and very little is known about what could have been a very exciting, 100 mph, vintage motor car. Michael McEvoy was a very well-known motorcycle manufacturer, at his works at Leaper Street in Derby. There he made a variety of models, starting in 1926. They ranged from a 175 cc McEvoy-Villiers to the fast vee-twin with the 45 bhp 998cc JAP engine, in rather a Brough-Superior mould, although I may be in trouble for putting it that way!
People like GW Patchett. who came from B-S, and CAC Bit-kin, brother of Sir Henry, were behind the venture and McEvoy rode his machines at Brooklands. He used engines that embraced the 1000 cc eight-valve Anzani and a three-valve-per-cylinder 350 cc of his own conception, and aroused much interest at Olympia in 1928 with a 500cc four which did not go into production, probably because the motorcycle side of the business closed in 1929.
It was at this time that McEvoy’s ideas turned to making this remarkable Hatton-McEvoy car. Freddie Hatton had studied engineering at Oundle and had taken up motorcycle racing professionally as a young man, riding in the Isle of Man TT and winning the 1922 750 cc BMCRC Solo Championship at Brooklands, on a 746 cc ohv Douglas. He also had a Douglas sidecar outfit. He then joined New Hudson, where he designed engines for them, and rode these machines at the track. By 1925 he was running his own business and racing Lea-Francis and Lagonda cars at the lesser Brooklands meetings. He was 27 when he linked up with McEvoy, to build this breathtaking motor car at the latter’s Derby works.
To keep its chassis price down to a modest £1000 simplicity was sought, but to have effortless high-speed performance a very large engine was specified. It was a six-cylinder of 110×170 mm (9700 cc), which in those times implied an annual tax as high as £45. Moreover, there were camshafts on each side of the crankcase, as on early T-head engines, but with push-rods running up each side of the cylinder block to operate overhead valves. Not only that, but there were four such valves for each cylinder. I do not know if this engine was an adaptation of an existing marine or commercial vehicle power-unit or whether McEvoy and Hatton made it themselves. It was certainly an advanced design. The Y-shaped valve rockers prodded two valves, so that 12 push-rods sufficed. The crankshaft ran in seven main bearings and oil was circulated through it. Pairs of cylinders breathed through separate induction pipes, from three car-type Amal carburettors. Two spark plugs per cylinder were fired by dual magneto-and-coil ignition and the wiring for the Lucas electrical equipment was duplicated to woo dependability, even to having two batteries, one of which could be recharged while the other was in service in the car.
Two oil pumps were driven from the camshafts, supplying the main and big-end bearings and even the con-rod little-end bearings, at up to 30 lb per square inch pressure. There was pump cooling, to a slightly vee radiator with a 4 in diameter filler-cap. This impressive engine, said to develop 260 bhp at 3000 rpm on a fairly low compression ratio, was three-point mounted in a chassis that was also distinctive. It was unusual in being very lowslung, achieved by having side-members that passed below the axles, with the long semielliptic springs above them. Stiffness of this frame was ensured by a combination of two centre tubular cross-members and channel-steel members front and rear, supplemented by dumb-iron tie-bars front and back. A unit four-speed gearbox had ratios of 9.0, 6.0, 3.5 and 2.4 to 1, and a 2.75 to 1 ratio was available. The gear-lever worked in a central ball-gate.
Lockheed hydraulic brakes were used, with separate shoes in the rear drums for the handbrake. Rudge centre-lock wire wheels took 32 in x 5 in tyres. Ground clearance was given as seven inches and the Hatton-McEvoy was to be available in two wheelbase lengths, 9 ft 8 in and 11 ft 2 in. Weight was around 27 cwt, the track 4 ft 8 in. Chassis only were to be made, bodywork being opted out. Although I have speculated as to whether some proprietary engine was encompassed, the partners declared that the power-unit and gearbox of the Hatton-McEvoy was constructed in the Derby factory, where all assembly would take place. The announcement was made early in 1929 and they were confident that the prototype, which they stated was “going ahead”, would be ready for testing at Brooklands before mid-summer. Yet no more was ever heard of this formidable car and as far as I know, only drawings of it have been seen!
Now we come to another speculative, but possibly significant, aspect. Laurence Pomeroy Jnr joined McEvoy before the war in selling and developing here the German-made Zoller supercharger. His famous father had left Vauxhall to go to America, where he promoted an all-aluminium car, prior to returning to the Daimler Motor Co in England. Now the drawings I have seen of the proposed Hatton-McEvoy bear a close resemblance to that low-chassis Daimler Double-Six which I once drove, a one-off venture by Thomson & Taylor at Brooklands. The steering column of the Hatton-McEvoy was near horizontal, as on the Daimler, possibly because the column terminated in a reduction-box on the bulkhead, from whence a vertical rod and bell-crank transmitted motion to the drag link. McEvoy seems to have adopted this system, but with duplicated drop-arms and drag-links, one for each front wheel. Not only that, but to keep weight down, alloys, such as duralumin and Y-alloy, were specified for many of his chassis parts. Pomeroy’s father was a firm advocate of such alloys and had incorporated some of them in the Daimlers he designed at about the relevant time. So I suggest that perhaps Pom, the son, who became technical editor of The Motor during and after the war, had at least a finger in the project at Derby. Including, maybe, some premature publicity for it?
The final conundrum is whether a car was ever completed. Certainly the price had been fixed, at £950 or £1000, and details such as fuel-tank capacity (20 gallons) and having individual switches for every lamp were settled. A clue is provided by a statement early in 1929 to the effect that no decision had been taken as to the type of clutch or back axle that would be used. One wonders if some Daimler parts were contemplated? The drawings I have seen depict a very exciting short chassis two-seater with cycle-type mudguards, a long louvred, strapped-down bonnet and rear-mounted spare-wheel, and a two-door coupe on the same lines. Was it all stillborn, or was a prototype constructed and perhaps tested? If anyone can supply more information about this sensational 9.7-litre, 24-valve British car it would be extremely interesting. Michael McEvoy went on to make McEvoy Special Morris Minors, Wolseley Hornets and Stars etc, and to promote the Zoller vane-type compressor.