Armstrong Siddeley 14 HP car – technical details

 

Armstrong Siddeley 14 HP Mark 1

 

I show here views of the chassis and engine for the Mark One and Mark Two Armstrong Siddeley 14 HP car.

This is the Mark One chassis for the 14 HP Armstrong Siddeley

The description in the handbook is “The four cylinder detachable head engine has a bore and stroke of 3″ x 4” (76mm x 102mm) giving a cubic capacity of 1,852cc. RAC rating is 14.4 HP and the British Tax £15.

The wheelbase is 9′ 3″ (2.82 metres) and the track 4′ 8″ (1.42 metres), the ground clearance being 10 1/8″ (257mm). Overall sizes are: Length 12′ 6″ (3.81 metres) and width 5′ 6″ (1.68 metres).” This ground clearance was with standard, beaded edge tyres of 30″ x 31/2″. Balloon tyres of 29″ x 4.95″ were fitted to meet popular demands.

The handbook goes on to say: “Cantilever road springs have been adopted to both front and rear, to avoid wear on shackles and the lubrication of same. As in the 30 HP and 18 HP models the gear box is mounted in one unit with the rear axle on the forward end of the tubular propeller shaft casing. This construction eliminates all moving parts in the mechanism between the gear box and rear axle. The ratios in the 3-speed gear box are 3.72, 1.836 and direct, the ratio on reverse being 4.73, and the final drive to the back axle is by spiral bevel with a reduction of 4.7 to 1.

 

Note the large flywheel, with single plate clutch in the centre, at the rear of the engine. The flywheel helped create a smooth running engine and improved torque at slow speeds. Unfortunately, it also made changing gear a slow process as with a crash gearbox (with no syncromesh) the driver had to wait when changing gear for the engine and gear wheel to slow down to match the gear to be engaged.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Below is the engine and chassis of the 14 HP Mark 2 which Armstrong Siddeley introduced in 1925.

 

Armstrong Siddeley 14 HP Mark 2 chassis 1925

 

 

 

 

 

 

 

 

 

 

 

 

On the Mark Two model Armstrong Siddeley introduced the tube over the engine linking the exhaust to the inlet to pre-heat the induction gases; the engine became known as the “pram handle”. Otherwise, the general arrangement of the engine remained unchanged: the engine had a Claudel Hobson carburettor; the magneto and dynamo was driven by a chain connected to the crankshaft and camshaft at the front of the engine. The starter motor was mounted above the flywheel.

The other significant changes were the improvements to the brakes and road springs. The Mark 2 had four-wheel brakes, rather than just two-wheel brakes as on the Mark 1, and semi-eliptic springs on front and rear axles, rather than cantilever springs. The changes improved the ride and overall performance of the car and made the model more competitive with other mid-priced 14 HP or 2 litre cars.

In 1926, Armstrong Siddeley changed the engine again, this time placing the exhaust and inlet on the nearside of the engine. The change meant that the inlet was directly pre-heated, but the negative affect of this was to create a more complicated inlet path within the engine and to move away from the efficient crossflow of gases in the earlier engine. The firing order is 1, 2, 4, 3.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Below is the final version of the 14 HP chassis from the 1928 catalogue showing the models for 1929, the last year that the 14 HP was sold. Armstrong Siddeley changed the design of the rear chassis, axle and springs to lower the ride.

 

Comparison of Armstrong Siddeley 15 HP and 14 HP chassis in final form as shown in catalogue issued in 1928 for 1929 models

A better view of the chassis for cars made 1928-9. Note the gate fitted above the gearbox and clustering of instruments on the dashboard.

 

Maintaining the 14 HP

I have found this article on maintaining and repairing the Armstrong Siddeley 14 HP a useful addition to the information in the handbook. It was published in Motor Commerce in January 1926.

 

 

 

The 14 HP, like other Armstrong Siddeley models, was supplied with a full toolkit. The Autocar magazine featured it as part of their test of the model published ?5 March 1926. The second image shows the car in the test bay. The article asked “How long does it take to attend to the various odd jobs, like lubrication, adjusting brakes and so forth, which must be done if the owner-driver wishes to keep the mechanism of his car maintained always in perfect running order”. Timings included greasing the chassis 9 minutes; cleaning oil filter 2 mins 36 seconds; testing and inflating tyres 10 mins 30 seconds; and adjusting all four brakes 13 mins 30 seconds. The total time for the year’s maintenance for 10,000 miles was estimated at 10 hours 39 minutes.

14 HP toolkit 1926

14 HP tourer in garage for The Autocar test, March 1926