Motors And Motoring
The 21/6o h.p. Arrol-Aster
Tun 21/60 h.p. Arrol-Aster is a six-cylinder, four-speed, six-brake machine which is undoubtedly of a good class. It soon imparts to driver or passenger that distinctive impression of luxurious travel which is one of the most-noticeable assets of the high-grade British car. This model, which is known as the ".0.V.21," has stood the _test of time, for only minor improvements have been made, from time to time, since it was brought out five years ago, yet it is up to date in design. Before giving my opinion of the running qualities of the five-seated fabric saloon, it is proposed to report briefly upon the chassis mechanism. The six cylinders, which are cast in one, have a bore and stroke of 75 and 115 mm., which make the engine capacity 3.048 litres. The valves work in the detachable head and the latter can be lifted without difficulty, and, if desired, with the whole of the valVe mechanism complete. The valves are interchangeable and are worked by pushrods, and these have the customary ball-and-cup connexion with the rockers. Valve clearance is adjusted by a ball-ended bolt which is threaded and which is secured by a pinching bolt. I prefer, in the main, a more positive method of faStning, although pinching bolts are a recognized form of locking. The valves have double springs, which conduce to quietness, and the oil which is forced to the engine bearings is taken up and delivered under pressure to the overhead valve gear. The supply here can be regulated. It is a minor, but good, point that the aluminium cover over the valve mechanism registers in the head and there is also felt. Thus oil leakage is not likely to occur. Too little attention is paid by many designers, especially those of American cars, to means of keeping an engine clean. The cover is held by two bandscrews, which, being permanently fastened to it, act as handles. The valve chambers are designed for turbulence, which improves the efficiency of the mixture. The camshaft is driven by a silent chain which is automatically tensioned and for which there is external means of adjustment. Such points as these save money in maintenance.
The crankshaft is carried in four bearings and has an Aster-Lanchester torsional vibration damper on the first throw. Aluminium-alloy pistons are used. In the valve cover on the near side there is the oil filler and this has a pull-off lid of sensible size and a strainer within. The exhaust manifold has a forward pipe connexion and thus overheating of the floorboards is avoided. The manifold is held by brass nuts which are easily unscrewed. The sparking-plugs can be removed without undue trouble and they are screwed into the block and not into the head. The generator and Magneto are driven in line by vernier couplings which make detachment a simple matter, while each electrical unit is held by a strap. It is just possible to see the make-and7bre-alc without a mirror, 'while the distributor, being vertically placed, can -be easily inspected. In front of the timing case there is a pulley by means of which the fan and water impellor are driven. The vee belt can be tensioned by reason of the top pulley being split. The gland of the impellor is regulable, but to repack it the fan must first be moved. On this the near side there are also the oil-relief valve and the float leieI indicator. The main oil filter cannot very easily be reached and a plug must be 'unscrewed to drain the sump. The former, however, is placed in the side of the base, and this last part is ribbed for cooling. The triple diffuser dual carburettor is on the off side and is water jacketed. There is a mixture controller to facilitate Starting. The petrol goes to the carburettor by gravity froth a vieuum tank on the dash. A fifteen-gallon reservoir is at the -baCk of the chassis, and, although there is no filter in the mouth of the filler, the filler is of proper size- and is to one side to make replenishment possible without disturbance of luggage. A worm and complete wheel are employed for the steering.
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THE TRANSMISSION.
The clutch is of the floating dry two-plate kind and betwee4 it and the gear-box there is a fabric universal joint. The engine; the f clutch, and the gear-b cos are assembled -together, the 'whole being held at`liiee points and• on lubber bushings. It is -a good point that the spigot bearing is automatically lubricated from the engine while the ring and stud universal joint in the torque ball housing just behind the gear-box also needs no attention as it is oiled from the box. On the top of the clutch housing there is an inspeetion plate which is detachable by hand. The starter is built-in to the near side of the clutch housing face which is cast in one with the circular gear-box. Clutch and brake pedals can be altered over a considerable range and both change-speed and pedal shaft are rightly independent of the frame. The gear-box has the fashionable arrangement of the shafts, namely, the lay shaft below the main shaft, and there are four forward speeds. Changes are made by an off-side lever which works in a visible or fixed type of gate and has a stop for reverse. The lid of the box can be removed with the least disturbance and there is a level filler on the off side. I like the fitting of three bearings to each gear shaft, as it tends to durability and quietness. The gear ratios are 4'2, 643, 10.2, and 16'8 to one on top, third, second and first. The low-pressure tyres measure 83 by 6 ins. Torque is taken by a tube which surrounds the propellor shaft and for the spherical housing in front there is an external grease valve. Good practice is followed by the provision of a central bearing for the torque tube and this saves possible whip and consequent vibration. Final drive is by spiral bevel which is housed in a banjo pattern of case which gives facility for withdrawing all the gearing without disturbance of the road wheels, springs, and so forth. The axle is of the fully floating kind and the case has a level filler. On the saloon tried the board under the back cushion made this somewhat difficult to reach. The six brakes are an advantage. The brakes worked by the off-side hand lever are placed side by side with the back brakes which work with the front brakes by pedal. Cables are used for the application of all six brakes and there are individual hand adjusters. An additional convenience is that either set can be primarily taken up by hand while the car is in motion. This is done by two handles which are placed just above the floor level to the off side of the driver. Since full compensation, namely, fore and aft and diagonally, is provided, once the shoes are properly set these handles will take up wear in effect throughout the sets. The front brakes work on the semi-servo Perrot principle in which the operating spindles have a universal joint at either end and anchorage to the frame. The brake drums are of ribbed aluminium and have cast-iron liners, which, of course, are renewable, while the shoes are of aluminium and faced with die-pressed anti-friction material. The front axle has rounded ends the better to withstand the torsional stress of front wheel braking, while the track rod is protected by being behind the front axle. The springs are half elliptical in front, held out of centre, and cantilever behind.
THE BODY AND THE RUNNING.
The body gives proper accommodation and is a five-seater. The car has a low and smart appearance yet head clearance has not been cut too fine. Four doors are provided, and there is a window in each door, while there are two small lights in the back and a blind can be drawn over these to save inconve- nience from reflection from following cars. The front seat is divided into two, and either part can be moved. I should prefer that the driver's seat would come more forward. Both cushions and squabs, in front and behind, afford adequate support. A leather cover is fitted over the gate of the change- speed, and this prevents undesirable draught, while the front screen is of novel design and can be lowered. Water is drained into a tank. Tools are in a sunk box in the near side running board, and the spare wheel is in a well in the off-side front wing. The battery, which is under the front floorboard, is to hand, and although it is the same size as the exhaust pipe, it should not be subjected to excessive heat in its position.
The saloon, as it should be for its engine size, has plenty of speed and the acceleration power is most satisfying. The engine ran quietly and is well balanced. The cooling was effective. The machine tested was new and not fully run in, but it would do twenty-five and forty miles an hour without undue pushing on second and third, and seventy should be within the compass of the car's capacity on the level on top. The clutch behaved properly, and it was possible to make late gear changes up and early ones down without scrape of any sort. With but two persons in the car the rear springs allowed too much wheel bounce on a rough road, but it should be possible to rectify this fault to a large extent by adjustment of the shock absorbers. The road-holding qualities of a car are clearly of most importance at high speeds, but makers are apt to overlook that cars are not habitually driven fast in this country and shock absorbers should be regulated to give good average results. Adjustment is, of course, but a small matter. With unsympathetic application of the four-wheel brakes the car tended to pull towards the off side, and one could feel this in the steering. In the ordinary way the compensating device should rectify this, but the car being new no doubt the shoe linings were not properly bedded down and final individual adjustment had not been given. The degree of power was fully satisfactory, and there was no sign of squeak or snatch. The hand-brake worked well. A moderate steering lock is provided. The steering action was at all times firm and free from undesirable shake, yet was light. There was plenty of power available for hill-climbing at good speed. The wheel- base and track of this model are 11 ft. 8 ins. and 4 ft. 8 ins., while the minimum ground clearance is 9 ins. Fully equipped, this 21-60 fabric saloon costs £795. A 17-50 h.p. six-cylinder Arrol-Aster is also made, and this machine has a single sleeve- valve engine, half-automatic chassis lubrication and silent type shackles which require no lubrication. The five-seater fabric saloon sells complete at £535. Arrol-Aster chassis and bodies are made at Dumfries.
The new 7 h.p. Morris is to be known as the Morris Minor. The specification includes a four-cylinder engine of 58 and 76 mm. bore and stroke, which make it of 748 c.c. capacity. The camshaft is overhead as well as the valves, and there is forced lubrication to all parts. Coil ignition has been adopted. The gear-box has three speeds, and the propellor shaft, which is enclosed in a torque tube, delivers the power to spiral bevel gearing in the back axle. Four-wheel brakes are provided, and the springs front and back are half-elliptical. The detachable wire wheels carry 26 by 3.50 ins. tyres. For the present the car will be marketed with full electrical equip- ment, including a starter, as a two-door fabric 2-4 seater saloon. At the time of writing the price is not fixed, but the firm state that this Morris Minor is not to be " the £100 car." Quality is not to be sacrificed to obtain a cut initial cost, and while this Morris will be distinctly competitive with any other machine that has so far been made it is intended to offer in it comfort, reliability, a good measure of safety, and strict economy both in operation and housing--the latter a point which is becoming of increasing importance. A car of this type will find a wide market, and not only with those who can but afford one small and inexpensive machine, but also among owners of large cars who have need of auxiliaries for the use of other members of the family and for saving the running of a big car where the service of a small one on occasion would suffice.
A third and fully revised edition of the Dunlop Guide has just been published by Messrs. E. J. Burrow and Company, Ltd., of Cheltenham. The Guide is in more handy form and has a well-defined map of Britain which is sufficiently detailed for touring purposes. There is in addition information about motoring rules and regulations as well as a list of ferries and steep hills, together with some practical hints on tyre main- tenance. The price of the Guide is five shillings.
YOUR MOTORING CORRESPONDENT.
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