Alvis Speed 25


The Alvis 4.3-litre and Alvis Speed 25 were British luxury touring cars announced in August 1936 and made until 1940 by Alvis Car and Engineering Company in Coventry. They replaced the Alvis Speed 20 2.8-litre and 3½-litre. They were widely considered one of the finest cars produced in the 1930s.

Alvis 4.3-litre
Sports coupé
by Mayfair Carriage Co 1937
Overview
Typecar
ManufacturerAlvis[1]
Production198
Model years1937 to 1940
Body and chassis
ClassFull-size luxury car (F)
Body style
  • 4-door sports saloon
  • chassis only also supplied[1]
Layoutfront-engine, rear-wheel-drive
RelatedAlvis Speed 25 3½-litre
Powertrain
Engine
  • 4,387 cc (268 cu in), 92 x 110 mm
  • Straight-6, Petrol
  • 137 bhp @3,600 rpm
  • 31.48 tax horsepower[1]
Transmissionsingle plate clutch, separate 4-speed gearbox all-silent

and all-syncromesh, centre change lever, open tubular propellor shaft

with metal joints (arranged in a straight line), spiral bevel fully floating back axle[1]
Dimensions
Wheelbase
  • 127 in (3,226 mm)
  • track 56 in (1,422 mm)[1]
Length191 in (4,851.4 mm)
Width70 in (1,778.0 mm)
Kerb weight4,144 lb (1,880 kg)
Alvis Speed 25 3½-litre
open two-seater
by Offord & Sons 1937
Overview
ManufacturerAlvis
Production1937–40
Body and chassis
ClassFull-size luxury car (F)
Body style
  • 4-door sports saloon
  • 4-seater drop head coupé
  • sports 4-seater
  • chassis for bespoke body[1]
Powertrain
Engine
  • 3,571 cc (218 cu in) 83 x 110 mm
  • Straight-6 Petrol
  • 106 bhp @3,800 rpm
  • 25.63 tax horsepower[1]
Transmissionsingle plate clutch, separate 4-speed gearbox all-silent and

all-syncromesh, centre change lever, open tubular propellor

shaft with metal joints (arranged in a straight line), spiral bevel fully floating back axle[1]
Dimensions
Wheelbase
  • 123 in (3,124 mm)
  • track 56 in (1,422 mm)[1]
Length190 in (4,826.0 mm)
Width70 in (1,778.0 mm)
Kerb weight4,088 lb (1,854 kg)
Chronology
PredecessorAlvis Speed 20 3½-litre [1]

New engines

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

Chassis

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

Coachwork

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]

gollark: No, actually.
gollark: Try opening control panel as admin or something.
gollark: Oh, you are?
gollark: Oh, are you not admin? Right.
gollark: Anyway, you probably **can** uninstall it.

References
  1. Cars Of 1937. The Times, Wednesday, 26 Aug 1936; pg. 8; Issue 47463
  2. Auto Motor und Sport Heft 12 Seite 117–118: >Modern updates easily exceed 100 mph. Der Alvis Speed 25 von 1939 besass einen Reihensechszylinder mit 3,5 Liter Hubraum, der bei 3800 U/min 110 PS leistete und das schwere Auto fast 160 km/h schnell machte. Stuttgart. 1974.
  3. Cars Of 1939. The Times, Saturday, 1 Oct 1938; pg. 8; Issue 48114.
  4. The Motor Show. The Times, Tuesday, 18 Oct 1938; pg. 9; Issue 48128
  5. Alvis Cars For 1940. The Times, Saturday, 26 Aug 1939; pg. 12; Issue 48394
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