ARMSTRONG SIDDELEY 17 hp

An article by Munro Donald on the model described by "The Autocar" for 28th September 1934 as "A car of useful but economical size, able to carry roomy coachwork of modern design, and essentially sound in the development of its design."

ARMSTRONG SIDDELEY 17 hp

Armstrong Siddeley cars had a reputation for quality, reliability and, perhaps a reflection of their performance, sobriety! They were never fast cars and Armstrong Siddeley made very little impact in the world of racing although they produced many "sports" models including a version of the 17hp. Armstrong Siddeley motor cars were however, popular with professional people and favoured by bank managers, solicitors and clergy etc.

"The Autocar" for September 28th 1934 described the Armstrong Siddeley 17hp on its launch at Olympia as "A car of useful but economical size, able to carry roomy coachwork of modern style, and essentially sound in the development of its design"

The 17hp came in many guises, most were clothed by Armstrong Siddeley's own inhouse coachbuilders "Burlington". They produced saloons, limousines, sports tourers, sports sloons, town and country saloons etc. The chassis was also popular with bespoke coachbuilders such as Salmons and Maltby's. The same article noted "The size of the engine will make the chassis suitable for colonial work, too, especially as the standard performance . . . . . is definitely higher than hitherto". Those were the days!
	The author's own 1936 17hp Siddeley, which has a 'Redfern' tourer body by Maltby.

These refined remarks seem a million miles from the hard hitting comments appearing in today's motoring press. It clearly was bad form to be either too cutting in one's criticism or indeed too effusive in one's praise!

Under the direction of John Siddeley, Armstrong Siddeley also developed and manufactured aero engines and perhaps this was sufficient outlet for their aspirations toward speed and excitement. Many of the cars manufactured by Armstrong Siddeley following the second World War were named after successful military planes powered by Siddeley engines; Hurricane, Whitley, Lancaster etc. In addition they made engines for military vehicles and indeed developed a number of military vehicles in house. Adverts for Armstrong Siddeley cars of the day often drew attention to their aircraft associations. This was less to suggest speed but rather the car's reliability. An advertisement appearing in "The Autocar" for August 11th 1933 announced another Armstrong Siddeley model as "A car of aircraft quality"

	The Armstrong Siddeley 17hp has a 6 cylinder OHV engine of 2,338 cc with cylinders and crank case in one very rigid iron casting, having four stiff bearings for the large crankshaft, the webs of which are provided with counterweights. Top speed is given at 68 mph and even today this model occasionally overtakes vehicles on the motorway, however these days the prudent owner ensures that the car is never pushed to the maximum.
Another shot of the author's 17hp

The article already referred to in "The Autocar" of September, 1934 said of this new model:-
"If it is true that the real virtue of an engine lies in the rigidity of crankshaft, then this particular power unit should be entirely free from all mechanical vice, whatever speed the crankshaft is called upon to develop in the future; the journal size alone is interesting to anyone who remembers the day when a diameter of this size would be condemned on account of rubbing speed theoretically far too high."

Illustration of engine to be added.

The article goes on to say, " At the forward end of the crankshaft a double roller chain distributes the drive to the camshaft, which is in the crankcase, and to a shaft driving the dynamo, the oil pump, fuel pump and ignition distributor being driven from the camshaft itself. Above the latter are tappets or followers, grouped in pairs operating two big overhead valves in each cylinder through push-rods and rocking levers. The rocking levers are hardened at the valve end, and provided with adjustable, hardened, ball ended screws at the push rod ends. There are two large coil springs for each valve, and an interesting sidelight on modern design, it is the valve diameter which governs the engine length as much as anything else."

"The number of necessary auxiliary drives has been reduced ingeniously by placing the centrifugal water pump on the end of the dynamo armature spindle. The flexible hose in the water pipes allowing the pump the necessary movement when the dynamo is swung to take up any slack in the timing chain. A new type pump gland has been adopted, tests having proved the gland to possess unusual durability"

The last sentence rather glosses over the advanced nature of the water pump, which featured a radically new design of seal. This uses a spring-loaded carbon thrust ring, rather than the traditional stuffing box. This design became commonplace in the post-war industry.

The car is fitted with the usual Armstrong Siddeley feature of a "Wilson" pre-select gearbox and from 1936 a "Newton" automatic (centrifugal) clutch was also fitted. The Wilson pre-select gear box was a common feature on Armstrong Siddeley cars of this time and continued to be used well into the 1950's. The gearbox is a separate component. The drive from the engine passes through a short very stiff shaft to the box which is itself slung between cross-members on a special mounting in a position where it interferes least with the seating in the car. Unlike some of the more expensive models produced by Armstrong Siddeley at this time the gear select pedal is not power assisted. This however is not a problem and the pedal is only a little heavier to operate than the clutch pedal on a modern car.

Driving using the Wilson pre-select gear box is reasonably effortless, if not terribly exciting. The combination of pre-select gearbox and automatic clutch was very advanced for its day and very attractive to many drivers who were at that time preoccupied with the often difficult task of changing gear quietly.

The "Wilson" gearbox was often advertised as the "silent gearbox", such was the importance of this feature to many people at that time. Unfortunately this is what often seems to put present day prospective owners off. Once you get the hang of selecting the gears in advance and engaging them with the pedal when ready it is a pleasure to drive and the automatic clutch makes handling in slow moving traffic effortless.

The gearbox itself is very robust being built to an extremely high standard and requires little attention other than checking the oil periodically with the dipstick and cleaning out the oil filter and changing the oil every 2,000 miles.

Specification for the Armstrong Siddeley Long 17hp:

• Wheel base 9ft 8 ins
• Track 4ft 9 ins
• Length 14ft 11ins
• Width 5ft 10ins
• Cylinders 6
• Valves o.h.
• Gear ratios 1st 20.4 to 1
• 2nd 11.65 to 1
• 3rd 7.5 to 1
• 4th 5.1 to 1
• Bore/stroke 66.67x114.3mm
• Capacity 2,394.5cc
• RAC rating 16.54hp
• Firing Order 1,5,3,6,2,4
• Oil pressure 25lb/sq.in.
• Carburettor Claudel Hobson downdraught*
• Tappet Clearances
  Inlet 0.004"
  Exhaust 0.012"
• Valve-timing Indication - camshaft and crankshaft sprockets
• Valve timing 5° B.T.D.C.
• Breaker gap 0.015"
• Plug gap 0.018"
• Ignition timing T.D.C
• Brakes Bendix (cable operated)
• Steering worm and nut 17in steering wheel

*Armstrong Siddeley altered this for models from 1938 to a VI Downdraught.