Alvis Speed 25

The Speed Twenty’s 2½-litre, 2.8-litre or 3½-litre engines with four main bearings were replaced in the 4.3-litre and 3½-litre Speed Twenty-Five with a strengthened new designed six-cylinder in-line unit now with seven main bearings.

For the 3½-litre version an output of 110 PS at 3,800 rpm was claimed (and proven) along with a top speed of almost 160 km/h (100 mph).[2] It propelled the occupants at high speed in exceptional luxury accompanied by the attractive sound of a powerful deep and throaty exhaust. Its beauty is also confirmed as it is the only car to win the prestigious Ladies Choice VSCC Oxford Concourse prize two years in a row. The clutch, flywheel and crankshaft were balanced together, which minimised vibration. The cylinder head was of cast iron but the pistons were of aluminium.[2] Two electric petrol pumps fed the three SU carburettors, which were protected by a substantial air filter.[2] A new induction system incorporated an efficient silencing device.[1]

Speed 25 engine 1939 showing new induction system and special hammer for knock-off hubs

Rear springs were 15 inches longer than in the previous model. The brakes had servo assistance.[1]

4.3-litre 4-door tourer by Vanden Plas

Profile: drophead coupé by Charlesworth 1938

Alvis did not make any of the bodies for the Speed 25. The cars were supplied in chassis form and firms such as Cross & Ellis (standard tourer) Charlesworth (standard saloon and Drop Head Coupé) as well as Vanden Plas, Lancefield, Offord and others would fit suitably elegant open touring or saloon car bodies.[2] The car was built on a heavy steel chassis with a substantial cross brace. With its sporty low slung aspect, all-synchro gearbox, independent front suspension and servo-assisted brakes, this was a fast, reliable and beautifully made car, although at almost £1000 it was not cheap. The survival rate for what was after all a hand-built car is surprisingly good. Later models featured increased chassis boxing, and to reduce the car’s weight Alvis cut numerous holes in the chassis box sections, which was also a solution tried less successfully earlier in the decade by Mercedes-Benz when confronting the same challenge with their enormously heavy Mercedes-Benz SSKL.[2]

Minor improvements

Minor improvements to both cars announced at the October 1938 Motor Show included a dual exhaust system said to quieten the engine and improve power output.[3]

From the show the press reported the 4.3-litre four-door sports saloon to have "a most imposing front with very large headlamps, fog and pass lights, and post horns."[4]

A chassis for bespoke bodywork was still listed but a range of standard coachwork was made available. On the standard four-door saloon there were no running boards and the wings were streamlined. The luggage locker was lined in white rubber. Dunlopillo upholstery eased muscular fatigue. The rake of both the driver's seat and its squab were now easily adjustable. There was a system of no-draught ventilation. The double sliding roof might be opened from either back or front seat. There were twin tuned electric horns and twin electric windscreen wipers. The instrument panel included a revolution counter and there were ashtrays and a smoker's companion.[3]

standard short-chassis 4-door saloon 1939

There were to be only detail changes for 1940[5]

Wikimedia Commons has media related to Alvis Speed 25.

• Alvis 4.3 litre -four door saloon & pillarless saloon by Vanden Plas- sales brochure 1936 (Including prices for fitted raw chassis, Standard Four Door Saloon, and Pillarless Saloon by Vander Plas)
• 4.3-litre Pillarless Saloon by Vanden Plas, 4-Door sports saloon by Arthur Mulliner and Alvis Standard 4-Door Saloon- sales brochure September 1936
• Alvis archive