The 9hp. A.J.S.

From "The Autocar". 1st August, 1930.
Sturdy and comfortable newcomer, designed for easy handling and for comfort.

The A.J.S. saloon follows modern lines.

Arduous experimental work and careful testing have been brought to a successful issue, and the long-expected A.J.S. car is now actually being produced. A. J. Stevens and Company (1914) Limited, is a progressive firm of the very highest standing in the motor cycle industry; indeed, only a week or so ago it again added to its laurels by winning the Lightweight T.T. race in the Isle of Man.

Hence it is expected that a small car produced by such a maker will most certainly be a sound engineering job. The new car, however, is definitely not intended as a speed machine. It is the family man’s utility vehicle, for town work or touring, large in the body, with plenty of head and leg room, economical enough in engine size to cut running expenses down to a minimum, yet sufficiently powerful to give a good performance without constant gear changing.

Besides having a good appearance, the new A.J.S. car has some individual points: the seating positions are not too low; there is plenty of leg room; there are wells in the back floorboards to give even more, and the instrument board occupies only the centre of the scuttle, so that tall men in the front seats are not in danger of barking their knees.

The mechanical specification includes a rigid and compact engine, with a three-bearing crankshaft, side valves, and a special form of combustion chamber which gives power and flexibility without harshness, an extra large fuel tank carried on the back of the frame, half-elliptic springs, Silentbloc bushes for the spring anchorages, shock absorbers for both front and rear axles, a 12 volt lighting set with big headlamps having electric dip-and-switch control, wire wheels, furniture hide upholstery, and chromium plating.

The A.J.S. will be produced first as a four-seater, four door, fabric-covered saloon, offered complete at £230.

Outwardly the car is of reserved aspect with a good finish, and well-balanced lines from the chromium-plated radiator, with its central bar at the front, to the folding luggage grid of neat oval section tubing at the rear. The wings are well-domed, fit closely without showing unsightly gaps above the tyres, and should be efficient in reducing the need for cleaning to a minimum.

Doors of more than normal width make entry into front or rear compartments easy. Separate front seats with tilting backs are provided, and with the aid of a spanner they can be adjusted to any one of four positions. Drop windows will be fitted to all four doors, the windscreen is a single panel with an outrigger method of locking it in position when open, and having screw clamps to lock it in the closed position. The vacuum operated screen wiper is carried on the bottom edge of the screen, which arrangement gives better vision in rain, and it is indicative of the care devoted to details that the suction tubing is of copper built into the body, and not rubber.

Armrests are provided for the wide rear seat - the whole body is schemed with the idea that it will hold four six-foot men in comfort - the rear window is wide and has a blind controlled by the driver. Mention has already been made of the compact central instrument board; this component is illuminated by concealed lamps from behind, and includes an ignition lock as well as a control for reducing the air supply to the carburettor when starting from cold. There is also a control within reach of the driver’s hand for shutting the cork-faced fuel tap. The fuel feed is by an Autovac, and, of course, it is an advantage to have the tank at the back of the car because it can be large, thus giving a good radius of action without refilling; in addition, the space in the scuttle is left free, and there is little likelihood of a smell of petrol in the body. Incidentally, the 8 gallon tank is suspended at three points on trunnions and is therefore free from the possibility of distortion. It has a contents gauge in the top, close to the filler spout, and is neatly encased at the back by a stove-enamelled cover plate.

Advantage has been taken of the freedom of the scuttle to build into it, under the bonnet, a really large locker for tools. One important point in the construction of the dash and scuttle is that the assembly forms part of the chassis and not of the body, so that the body can easily be dismounted at any time without disturbing any electrical wiring.

Dealing with the mechanical aspect of the machine, the engine, which develops 24hp. at 3,000r.p.m. is an entirely new design of straightforward character, but possessed of some special detail features. It is rated at 8.9hp., and comes into the £9 tax class, the bore being 60mm and the stroke 90mm (1,018c.c.). The four cylinders and the greater part of the crank case are cast in one block, the case being carried down well below the centre line of the crankshaft, so that the support for the three main bearings is particularly stiff. The shaft is dynamically balanced during manufacture. A pressed steel sump is employed to close the base of the engine.

Side valves of special quality steel are employed, and are operated through mushroom-ended adjustable tappets of cast iron, with faces chilled in a special manner. The combustion chambers are designed in conformity with the Whatmough principles of streamline gas flow, the shape being depicted in one of the accompanying sketches. The result of this shape is to allow a compression ratio of 5.75 to 1 to be used, thus giving plenty of power, but avoiding any tendency towards detonation or ‘pinking’ and giving very smooth running, besides an ability to pull down to extraordinarily low speeds without rough running.

Actually, the car can be driven up a slope until the engine nearly stops, but there is no thumping. This means that top gear can be used almost entirely in traffic, the need for gear changing, except after actually stopping, being at a minimum. Great care has been taken with the cooling system, which is on the thermo-syphon principal. Water spacing is given between all four cylinder barrels, and the valve ports are arranged so that the metal of their walls is entirely surrounded by water. The flow enters the block on the valve side, is graduated to pass evenly around the valve seats and ports, proceeds afterwards up to the head and then returns to the large radiator. There are no thin divisions in the cylinder head gasket; the head is held down by no fewer than eighteen bolts, and the general design is particularly good. Decarbonising should be easy, and also not often necessary.

There is special interest in the gas distribution system. The exhaust manifold has in its centre a pocket to retain heat. This pocket is carried downward and meets the centre of the inlet manifold. The gas mixture from the Solex carburettor plays on to the wall of the pocket and is warmed, after which it proceeds through partially insulated pipes up to the inlet valves. The system works well and gives that capacity to open the accelerator wide and suddenly, in order to obtain clean acceleration away from a low speed on top gear.

Like the rest of the design, the lubrication of the engine is well arranged. A gear pump of unusually large size is driven from the centre of the camshaft. It draws oil from the big cylindrical filter in the sump, via a non-return valve, and then delivers it under pressure through large diameter machined oilways to the three main bearings and the big ends, to the three camshaft bearings, and to the timing chain. The sump contains six pints. A gauze tray over the sump filters the oil a second time before it returns into circulation. The cylindrical filter can be detached downwards from the bottom of the sump for cleaning purposes. A dipstick in the side of the sump is used for testing the oil level, and the oil filter is placed high up at the front of the engine.

Returning again to the moving parts of the engine: the connecting rods are of nickel steel and have the gudgeon pins fixed in their small ends. Pistons of special aluminium alloy have three rings in the head and a scraper ring. The alloy permits a close piston fit. At the front of the engine block is a compartment containing the duplex roller chain, which provides a triangulated drive from the camshaft to the camshaft wheel and the dynamo. The last-mentioned component is mounted high up in a position where it is accessible, and is arranged so that it can be swung bodily for adjusting the chain tension. On the remote end of the dynamo spindle is a vertical drive to the contact breaker and distributor of the coil ignition set.

In a casing at the rear of the engine is the flywheel, which contains a single dry-plate clutch. The driven member of this is radially slotted, and the segments are set slightly out of plane to give a sweet first engagement when moving away from rest. Clutch adjustment is made through a cover plate, there being set-pins for the purpose in each of the three toggle arms which control disengagement. There are six radially placed clutch springs which are adjustable. Bolted to the flywheel housing is the three-speed gearbox of normal design, having a central change, and an enclosed drive for the speedometer. Oil is filled into the box through a plug at the top, a second plug at the side being undone during the process, so as to prevent over filling.

Drive is transmitted to the built-up type rear axle through a massive tubular propeller shaft with a splined telescopic slide at the forward end, and with Hardy disc flexible couplings at both ends. These couplings have ball centring sockets which are automatically lubricated. Inside the centre casing of the rear axle is a spiral-bevel final drive and a bevel differential. Semi-floating axle shafts are used. The brake drums, both front and rear, are carried by the wheel bolts, and are easily removable for inspection of the shoes - a matter of no small convenience to the owner. The rear hub brackets and bearings are also very accessible.

Expanding shoe brakes are fitted to all four wheels, and are operated through tie rods and levers. Adjustment is carried out through an individual setting on each brake bracket. There is no compensation. To comply with legal regulations, the front and rear sets are operated independently, the right-hand lever applying the rear set, while the pedal applies the front brakes; but there is a trip link which transmits the movement of the cross-shaft of the front brakes to the similar cross-shaft which operates the rear brakes, the result being that depression of the pedal applies all four brakes simultaneously.

There is an unusual type of steering gear, which in practice proves very light and pleasant to handle, whilst a fair amount of caster action makes for steadiness. The gear consists of a worm mounted on the lower end of the steering shaft, which passes through a nut carried in a fork mounted upon the spindle of the steering drop lever. At the top of the column is a self-aligning ball bearing. This gear works very freely; it precludes, however, the fitting of engine controls at the centre of the steering wheel, so these controls are very neatly mounted on the column beneath the wheel.

Practically straight-sided, inclining inwards towards the front, the channel section side members of the frame are stiff, and are braced by four cross members. The middle members are attached below the sides and pass underneath the shaft.

It will be realised that the detail design of the car has been carefully thought out; hence this newcomer may be expected to render a good account of itself.

This new car is on-view at the showrooms of H. Taylor and Company Limited, 49 Sussex Place, S.W.7. The London agents.

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