The Armstrong Siddeley Sapphire 346

Production period	1952 to 1958
Number of cars produced	7,697
Engine	6 cylinder, 3435cc, 125BHP @ 4,400RPM
Body styles	4-door 4-light & 6-light Saloon Limousine
Transmission	Manual Pre-selector Automatic

The Sapphire 346 was produced between 1952 and 1958, with a total production of 7,697 vehicles.

The Sapphire was a completely new design and shared nothing with the 16/18 hp range of cars. The engine was 3.4 litres, square in dimensions having a bore and stroke of 90mm, and featured efficient hemispherical combustion chambers. The valves were operated by a single camshaft positioned in the block, via unequal length pushrods. This system was much simpler than an overhead camshaft with the necessary long driving chains. Both the block and head were of cast iron, thereby avoiding the potential corrosion that occurred in cast alloy engines when incorrect coolant was used. This was a powerful engine that at release, in single carburetor form, produced 125bhp. It was an amazing engine with 2 distinct characters. It was capable of being driven sedately at low revs and yet was equally happy at the maximum recommended engine speed of 5000 rpm!

The car was offered initially with manual or preselective transmission. New for the Sapphire was an electric control system, the driver changing gears via a miniature gate and switch shaped like a gear lever. Both 4 and 6 light saloons were offered. The chassis incorporated progressive deformation characteristics front and rear – for many other car makers such advanced crash safety was decades away.

In 1954 a twin carburetor option was introduced lifting power to 150bhp @ 5,000RPM.

In 1955 a long wheel base Limousine was introduced

In 1955 the Sapphire was updated and the earlier cars retrospectively referred to as Mk1s.  The Mk2 Sapphire incorporated the following changes.

• Availability of automatic transmission 
• Larger power assisted brakes
• Optional power assisted steering, electric windows and adjustable rear shock absorbers.
• Changes to the instruments and replacement of the semaphore with flashing trafficators.

Production of Mk2 saloons ended in 1958 and Mk2 Limousines in 1959 to make way for the Star Sapphire.