THE 16-66 A.C.
A FAST SPORTS CAR WITH UNIMPEACHABLE MANNERS. LE ” poids, c’est l’ennemi ” is the slogan of a famous Continental firm specialising in small cars, and the makers of the A.C. Ace have borne this fact in mind when settling the specification of their sports model. Fitted with a small but comfortable four-seater body and an efficient two-litre engine, the “
16-66″ is one of the liveliest and yet one of the most effortless medium-weight cars we have handled.
From the minute that one takes the steering wheel, the car seems eager to thread its way through traffic, to overtake slower vehicles and generally to put up a good average under rather unfavourable conditions. The good power-weight ratio allows this to be done without much recourse to the, gears, but when required these operate with certainty and refinement. A useful feature is the way in which the lever can be clicked from top to second gear when running slowly in traffic. Top gear is “forward right” instead of back right,” but one soon becomes accustomed to this.
For some reason not easily apparent the springing of the A.C. did not seem to suit the rougher parts of Brooklands Track, but few of its owners would want to use it there, so this is not an important matter. With the windscreen down the car achieved the useful timed speed of 80 m.p.h. over a half-mile, and a comfortable 75 in the raised position. Straight petrol or benzol mixture is the normal fuel, but since there was a fair amount of carbon in the engine, the tests were carried out using Pratt’s Ethyl.
The crank-shaft damper was out of adjustment, and there was considerable vibration above 4,000 r.p.m. We therefore did not exceed these revs, except on top gear, but in spite of this the acceleration was very satisfactory. The road speeds at 4,000 r.p.m. were 74, 54, and 35 m.p.h. respectively. The speedometer was dead accurate.
To get good road holding at high speed it was necessary to have the tyres and shock-absorbers rather hard, but this does not make driving uncomfortable, as the driving position is a good one and the upholstery gives support where needed. Top gear is fairly low, and for fast runs on main roads little gear-changing is required. The engine runs quietly, with a subdued exhaust note, and full throttle can be given without the driver feeling that the car is working hard.
If there is occasion to hurry, the car maintains a steady 70 m.p.h. without effort and takes fast curves in good style, and 65 can be held up Dashwood, Benson and other main road hills with gradients round 1 in 10. Third gear is useful, and when the vibration damper is properly adjusted one can get some 60 m.p.h. at 4,500 r.p.m. The car was driven about a hundred miles practically flat out and seemed to enjoy it, the only complaint being that the cockpit became rather warm. This will be overcome on later models by fitting scuttle ventilators.
The tourist as well as the fast driver is catered for and the car is almost inaudible cruising from thirty to fifty miles an hour. It will run at under ten miles an hour on top gear without snatch, though the simple gear-change generally encourages changing down at an earlier stage. Hand and automatic ignition control is fitted, and the lever never needs to be touched except for starting.
The driving position brings all controls within easy reach, and the steering wheel is well placed for fast motoring. The steering itself is light without being low-geared, but we should have preferred a little more caster. The body is cut away to,clear the driver’s elbow, and the body is wide enough to allow the arm to be kept inside in wet weather. The clutch is light and takes up the drive smoothly, but when fully depressed for getting away from a standstill, the foot-plate takes up an awkward angle. The gear-box, which has a remote control lever, is particularly good and there is
a real satisfaction in handling it, apart from the usual enhanced performance
which one gets by a judicious use of the ” indirects.” Third gear, which employs constant mesh pinions, runs quietly and is close to top gear, and second, which is generally used for starting on the level, is almost as silent as third gear.
The brakes were progressive in action, with plenty of power as the pedal was fully depressed, but on the car we tested the front ones came on too early. This could have been rectified if it had been realised that the latest Bendix brakes can be adjusted by a simple hand control on each back-plate, but under the circumstances 66 ft. was required from 40 m.p.h. As will already have been gathered, the special feature of the A.C. car is that even when driven hard there is no sensation of stress or overdriving, the silence and smoothness of the engine contributing largely to this, and the power-weight ratio is favourable enough to make one think that a higher back-axle ratio would further extend the performance. With a higher compression and a high-lift cam
shaft, in fact, the A.C. might well show to advantage in such races as the Belgian Ten Hour, or the Ulster T.T.
The A.C. Company were the pioneers of the Light Six engine, and the latest models retain some of the features which were so revolutionary in 1924.
The cylinder block and the top of the crank-case form a single aluminium casting, with hardened steel liners completely surrounded by water. Owing to the disposition of the crank-shaft bearings the liners are grouped in three pairs, each pair being sealed at its lower end by a gasket shaped like a figure-of-eight, while a single gasket is used at the top end. This form of construction brings with it an important saving in weight, and the complete two-litre engine only scales 325 lbs.
The crank-shaft has four bearings, and a damper is incorporated in the flywheel. Plain bearings are used for the mains and the big ends.
A steel cylinder-head is used with inclined valves in hemispherical chambers. The valves are operated by rockers from a single overhead camshaft which is driven by chain from the rear end of the crank-shaft.
A cross-shaft drives the dynamo and distributor, and as the former is mounted with its axis at right angles to the crankshaft, the brush gear is particularly accessible.
Three S.U. carburetters are used, supplied by an electric pump from a 10-gallon rear tank. The battery and the tool box are carried under the bonnet, likewise a spare set of sparking plugs, and the good finish of engine and the polished wood tool box will appeal to those who take a pride in the less visible parts of the car.
A single-plate Borg and Beck clutch is used, with a dry thrust-washer and a special form of construction which makes adjustment unnecessary. The four speed gear-box is mounted on a bell-housing in unit with the engine. Four point suspension is used. The transmission is of normal type, with an open propellor shaft and spiral bevel final drive. The chassis is a fine piece of work, with a central cross bracing. The front extremities are joined to the chassis at
points level with the gear box while the rear limbs strengthen the frame where it carries the rear spring hangers. A further cruciform member under the petrol tank braces the rear portion of the chassis. The side members are upswept in front and pass under the axle at the rear. The springs and shock-absorbers are carried outside the chassis members, and the last named can readily be adjusted. The front shockabsorbers, are mounted transversely, and like those at the rear, are of the friction type.
Bendix duo-servo brakes are used and they operate in ribbed drums.
The lines of the four-seater body leave nothing to be desired and the car tested, which was finished in grey with blue lining on the edges of the bonnet louvres, attracted favourable attention everywhere. The underslung chassis permits a low body line which is not, however, carried to excess. The front seats are upholstered with Dunlopillo, a cellular rubber composition, and covered with leather. This construction gives softness without swaying, while there is ample leg-room for a six
foot driver. The body has been arranged to give comfort for two without unnecessary width. The rear seats are cornfortablp too, but the position of the crossbracing prevents wells being fitted for the full width of the floor. One full-sized passenger would have ample room, but two would be cramped on a long journey.
The all-weather equipment is good, the side-curtains being secured by handscrews with tapered shoulders. When out of use the side-curtains are stored in the usual pocket behind the rear squab. A luggage locker large enough for two suit-cases is fitted in the rear of the body, and is reached by swinging back the hinged rear panel.
The price of the four-seater A.G. is £450, which seems very reasonable in view of the fact that it is hand-made throughout.
The address of the manufacturers is A.C. (Acedes) Cars, Ltd., Thames Ditton, Surrey.