Classic Car Catalogue

Armstrong Siddeley 1933

Great Britain

30 HP Mk II - ost rok (?)
Short 20
Special 20 / Long 20
Special Mk I (R6, ohv, 4960cc, 124bhp)(11'0''/12'0'') – new model

Armstrong Siddeley Saloon on 15 HP Long chassis. Long chassis has a 13 ft 9 in wheelbase, compared with 12 ft 10 in for the normal 15 HP. Both types has 2169-cc side-valve engine, self-changing four-speed gearbox and permanent jacks.




Motor SportJuly 1933

The Armstrong-Siddeley Rally Tourer.
TO the really enthusiastic driver, who is not compelled by his profession to carry out his business in a closed vehicle, the open car is the only one which gives the full joys of motoring. Models of this type figure in most cases only in the programme of sports car manufacturers, and are either of moderate price but with limited passenger accommodation or full-sized cars marketed at a high but quite justifiable figure. The Armstrong-Siddeley Rally Tourer bridges this gap, since it is a full four-seater of sporting appearance, but is not intended for speeds round the 90 mark, and therefore can be produced at a lower price than its sports rival. At the same time by virtue of its large engine and self-changing gear-box, it can show an acceleration at the lower end of its range which would allow it to hold its own in traffic or at normal touring speeds, or even in stop and restart tests, should the driver wish to take part in trials or rallies.
The six-cylinder engine which is carried at four points on thick rubber washers, has overhead valves, push-rod operated, and the adjustment is carried out with a ball-ended screw and lock-nut on each rocker. Oil is led to each rocker, thence through oilways to the part which bears on the valve and to the push-rod cup. The crank-shaft is carried in four bearings, with a torque-damper at its forward end and a silent chain at the front of the engine drives the four-bearing camshaft, and the auxiliaries mounted on the off side of the engine.
An A.C. petrol pump feeds the Claudel-Hobson carburetter from the 12 gallon rear tank. The inlet and exhaust manifolds are parallel on the near side of the engine, with a large hot spot in the middle, and the exhaust gases are led away from the front end of the manifold. The distributor, dynamo and water-pump are all accessibly mounted on the off-side of the engine, and the Tecalamit filter, the oil filler, and the level indicator are all close together. A pedal-operated one-shot lubrication installation is mounted on the dash.
The working of the famous Armstrong-Siddeley self-changing gear-box is so familiar to most people that little need be said about it. First, second, and third gears are obtained with trains of epicyclic gears, which are brought into operation by friction brakes. Instead of relying on a separate train for each gear, for second and third gears the reduction is divided respectively amongst two and three trains. In this way the tooth pressure is kept low, and all ratios are silent and long-wearing, besides showing an efficiency as good if not better than is obtained with the conventional gear-box. Top gear is a direct ratio, effected by a cone friction clutch within the gear-box.
The acceleration chart.
No clutch is required, owing to the action of the friction bands in the gearbox, and the drive is transmitted from the engine through a short shaft with two universal joints. The gear-box, which is mounted at the forward end of the torque tube, is carried at its front end by a universal joint in a cross-member, and the torque is resisted by a bracket ending in a ball, operating in a housing also mounted on the cross member. The final drive is by spiral bevel.
The chassis is of normal type, adequately braced. Suspension by semielliptic springs with Luvax shock-absorbers. The Bendix semi-servo brakes are operated by enclosed cables and the brake drurns are stiff and well-ribbed.
The sloping lines of the Armstrong radiator always seem to suggest steady and effortless progress, and we felt at home and ready for a journey of any length a few moments after taking the wheel. The Twenty is a large, roomy car, not feel clumsy, and as one sits fairly high, the near-side wing is not hidden by the bonnet. The only initial criticism one could find was that the hand-brake lever was a little short, and therefore not too convenient in traffic.
On a Surrey "Alp". The Armstrong-Siddeley rounding a hairpin of the Box Hill Zig-Zac.
The car which was being tested had only run about 500 miles, apart from the running-in which the engines receive before going into the chassis. A maximum speed of just under 72 m.p.h. was creditable under the circumstances, and one would expect another 3-4 m.p.h. when the car was fully run in. More important to the normal user of the car is the rapidity with which it reaches speeds up to 50 m.p.h., a rapidity usually found only in the less tractable sports car. Much of the credit must be given to the self-changing gear-box which allows instantaneous changes to be made, even with the accelerator hard down. Comfortable maxima in the gears are 18, 33 and 50 m.p.h. when the engine speed is about 3,500 r.p.m.
The brakes were exceptionally powerful, and from 40 m.p.h. brought the car to rest in 52 feet, but through being slightly out of adjustment, one of the back ones was inclined to come on harder than its fellow. In spite of their powerful action, there was no tendency towards snatch, and the retarding effect was progressive as the pedal was depressed.
The four essentials for fast touring are:—good acceleration and brakes, good steering and stability. The first two have already been remarked on. The steering, which has a worm and nut mechanism, was light without being too low-geared and had plenty of caster. The suspension was flexible at all speeds without unsteadiness being felt when corners were taken at high speeds.
The efficiency of the self-changing gearbox has already been commented upon, but at first we found it difficult to move the control-lever, which is mounted on the steering wheel boss, to the notch representing the gear we wished to pre-select, without having to look down. A lighter movement with deeper notches would be an improvement. Once the feel of the control has been mastered, of course, the smooth and instantaneous gear-changes which can be made put the car far ahead of vehicles of similar power equipped with sliding pinion gear-boxes. All the ratios are silent-running, and the bands take up the drive as smoothly as the ordinary clutch. The actual change is made by depressing the pedal which is normally used to operate the clutch. After pressing it right down, it is allowed to come up again and gradually engages the gear which has been pre-selected.
The workmanlike power-unit of the Armstrong-Siddeley Rally Tourer.
With its high top gear of 4.1 to 1, the Rally Tourer covers fast main roads with the minimum of fuss, 55 m.p.h. being the normal touring speed, with another easy ten m.p.h. in hand if one wished to put the pedal down further. On the winding and fairly narrow roads of Surrey, the same speed could be maintained, and there was nothing in the way the car handled to remind one that it had a wheelbase of over 10 feet. Third gear, which is labelled "normal" on the control, is very useful under such conditions, and by taking advantage of the flexible engine, one seldom has to drop lower. Second would deal with accelerating from sharp corners or hair-pins, and with any hill which one would expect to meet in England, but the maximum speed is of course not very great. Not having any Alps handy in the South of England, there was no chance of finding gradients which would have afforded a real test, but the way in which the car bounded up Box Hill Zig Zag gave one an inkling of how the car would behave in mountainous country. It will be remembered that Armstrong "20's" won three Coupes des Glaciers in last year's Alpine Trial.
In the sub-heading of this article the expression "armchair comfort" will be noticed. This was not intended to be a metaphor. The front seat has a central folding arm-rest, and another is fitted to each door. These in conjunction with an ample pneumatic cushions and high backs to the seats do ensure that driver and passenger are supported at every point, and the steering wheel and controls are arranged so that they are all in the driver's reach without changing his position. A more comfortable lay-out for long, fast journeys could hardly be conceived.
The back seats are similar to those in the front, though the comfort of the occupants would have been improved by having some sort of ramp against which the feet could be rested. This would not be difficult to arrange. With the centre armrest folded back the rear seat would hold three people, and the same applies to the front seat, as it is not obstructed by a central gear-lever.
The coachwork, which is built at the Armstrong-Siddeley Works is solidly constructed and finely finished, fittings such as door handles and locks reproducing the Sphinx motif of the radiator mascot. The radiator cap comes off with half a turn, and the petrol filler-cap is permanently held by a spring inside the tank, but hooks out of the way when it is being filled.
No point has been overlooked to make the Rally Tourer a fast, safe, and effortless touring car, and we welcome the return of this useful type.
  Event: Entered: Raced: Finished: Best results:
14-18.03.1933 R.A.C. Rally       21 H. E. Symmons 4980 cc 16 hp→ 5th

H. E. Symons' Special Tourer in the R.A.C. Rally.