ALVIS ANNOUNCE A NEW 3-LITRE CAR
A six cylinder rated at 25.63 h.p. All synchro-mesh gear-box and independent front-wheel suspension. the Speed Twenty, the Silver Eagle and the Firebird, continued with small modifications Other models,
With the introduction of a new 31-litre car for 1936, the Alvis Car Company has made a notable contribution to the de luxe sports cars which are available on the British market. The engine is entirely new, but naturally embodies some of the successful features of the Speed Twenty engine. Independent front-wheel springing, the unique Alvis gear-box, and the special brakes all figure in the specification, and the new car should be eminently suitable for attaining high speeds and maintaining them with a minimum of effort.
The bore and stroke of the engine are respectively 88 and 110 min., which gives a capacity of 3,571 c.c. The R.A.C.
rating is 25.133 h.p. Push-rod operated overhead valves are used in a detachable head, and the use of a number of Small spiral springs set round the valve instead of the more usual concentric pattern gives unusual silence in operation. One sparking per cylinder is Used, and the ignition is normally by means of a polar inductor magneto, with coil ignition for easy starting and emergency use.
Three S.U. carburetters are fitted, and the petrol is drawn from the 17-gallon rear tank by means of electric pumps.
The crankshaft runs in seven plain bearings and the camshaft is chaindriven from the rear end. The pistons are of aluminium alloy and the connecting rods have the big-ends die-cast in place. Lubrication is by rotary gear-pump driven by spiral gears from the camshaft providing forced lubrication to crankshaft, big-ends, camshaft and valve rockers. The cooling arrangements are Unusually thorough and should make the car eminently suitable for use abroad. Water is forced to the large honeycomb radiator (which has a neat slatted stoneguard), by means of a pump, and a belt-driven fan
is also fitted. Special external water passages between the head and the cylinder-block prevent any chance of leakage from a faulty gasket.
A single-plate clutch is used, and the gear-box is mounted independent of the engine. The box is of exclusive Alvis design with constant-mesh gears, silent on all ratios, and with all changes by means of synchro-mesh mechanism. The gears are controlled by means of a Short central lever. The normal gear-ratios are 4.11,
8.34 and 12.95 to 1 with a 14.39 to 1 reverse, hut a 4.33 to 1 back-axle ratio 18 also available. An open tubular propeller shaft is used with two universal joints. The rear axle is fully floating and the differential case is a steel drop forging. The final drive is through spiral bevel gears.
The chassis is particularly sturdy, swept up in front and sharply carried up over the rear axle, with detachable bracing pieces bridging the gap. A particularly sturdy cross member with a slot for the propeller shaft braces the chassis at the front end of the rear springs. The successful design of front-wheel springing, already a feature of the Speed Twenty is also used on the 31-litre. A transverse cantilever leaf spring is used, and each wheel swings on a parallelogram formed by half the leaf spring, ‘a vertical link, and a second link parallel with the leaf-spring The rear springs are underslung half-elliptics and Andre telecontrol shock-absorbers are used on both axles. The four-wheel brakes are of special Alvis pattern, cable operated by the pedal
and the hand lever, and no part of the mechanism is in torsion. The shoes operate in 14-inch ribbed drums.
The wheelbase is 10 ft. 4 in., the track 4 ft. 8 ins., and the chassis weighs 23 cwt. The chassis equipment is of de luxe character, specially practical items being the Lucas P.100 headlamps and the two ” Passlights,” the one-shot chassis lubri
cation from a tank on the dash-board and the four wheel jacks.
At the Moment the 31-litre is only quoted in chassis form, the price being X775, but complete cars will be seen on the Olympia stands of Messrs. Vanden Pins, Charlesworth Bodies, Ltd., and Lancefield Coachwork, Ltd.
The Speed Twenty which has a sixcylinder engine of 2,762 c.c. is being continued with feW alterations and its features of independent springing and the -all-syncho box place it well in the forefront of design. This gear-box is also • used on the smaller 0-cylinder Silver Eagle and on the Firebird, which has a 1,842 c.c. four-cylinder engine, but the two latter tars are fitted with springing of the conventional type.