Three interesting Alvis cars
ALVIS cars, from the advent of the original "10/30'' in 1920, have always had a fine reputation, and much interest still exists in the pre-war models. The writer has owned five "12/50"s, a " 12/60," and a "14/75," and this make therefore finds a particularly soft spot in his heart.
Last year Motor Sport described in some detail the special 1934 Speed Twenty of K. Smith and Peter Waring's modified 1932 Speed Twenty, today owned and raced by G. Worsley. Reacquaintance with the make was made recently during a visit to Michael M. B. May's home in Surrey. Standing in his coachhouse were his famous green "racer," an early Silver Eagle fabric tourer in process of being rebuilt, and his present means of "gentlemanly" transport, a 1940 3 1/2-litre Speed Twenty-Five Charlesworth saloon.
Desiring to visit the flying dub where he keeps his Auster and noticing our covetous glances at the first-named car, Michael elected to use this for the run. It will be recalled as one of the 1930 "Double Twelve" 2-litre Silver Eagles, into which a 2 1/2-litre triple-S.U. engine was afterwards installed, and the brakes converted to Lockheed actuation.
On the run in question May bewailed the reluctance of the engine to "rev." the petrol/benzole brew being decidedly stale. But there was no denying the "real motor car" appeal of this Alvis. The body, largely the "Double Twelve" original, is narrow, but comfortable. Visibility front the high bucket, seats is all of 100 per cent, yet a tall screen adds real comfort to the dice. The long outside hand brake, accessible inside r.h. gear-lever and cord-bound wheel were noted with approval, and in gear noise and engine bark the old green Alvis is the "real thing" all right! Stripped it has lapped Brooklands at 113.97 m.p.h. and the Campbell circuit at 65.82 mph, and technical details were given in Motor Sport for June, 1941. ln road guise it does just about the "century."
To provide striking contrast. May next suggested a drive to Newlands Corner in his newly-acquired Speed 25 saloon. This spacious car is very fully equipped, with Telecontrol of the shock-absorbers, one-shot chassis lubrication, heater, radio, wind-screen squirts, etc. There is a useful dashboard stowage compartment, speedometer and rev.-counter are at opposite ends of the facia panel, incidentally, and both wings are easily visible from the driver's seat. Many components of this comparatively recent Alvis are interchangeable with those of May's Silver Eagle and the r.h. handbrake lever is like that of a "12/70," or "12/50" for that matter! A slender central lever, however, changes gear in the big all-synchromesh box, the action very pleasant and road-holding, aided by i.f.s., with a massive transverse leaf spring, is of a high order; 65 m.p.h. came up as a matter of course along any bit of straight road, the steering was light, the brakes reassuring and, as its owner observed, this car seems a very good proposition, providing almost all the performance and comfort of 1951cars costing nearly five times as much. The only snag was a fuel consumption of about 11 m.p.g., but May had not then had time to tune the triple S.U.s.
The next Alvis we sought out was the exciting looking 4.3-litre raced by B. Chevell. He not only proved very willing to lay it bare for us, but drove the writer 30 miles home afterwards. That run was truly exhilarating. There is the sense of being in a big car, one, indeed, nether reminiseent of a Brooklands outer-circuit machine, yet as the weight is only one ton dry and some 150 b.h.p. is available, acceleration is of truly "hit-you-in-the-back" variety and, up to 90 m.p.h. at all events, leaves behind XK 120 Jaguars. The view over the lengthy bonnet, with its raised air-scoop, is superb, both front wheels, as well as the substantially-stayed fixed cyclewings being visible. The non-i.f.s. suspension provides an excellent balance of flat-ride and comfort, the cable brakes really pull the car up, the clutch needs care in engagement, but the all-synchro gearbox is a treat, and when the throttle is opened real animal-power is unleashed, accompanied by a most raucous exhaust not - yes, exhilarating!
Chevell bonght this AIvis, then a Speed Twenty, as art ex-farm hack in 1946. It was stripped, the frame cut to 9 ft-wheelbase and a new underslung back-end fabricated and welded-on and the engine moved back 12 in. The compression-ratio was raised to 8.5 to 1 by removing the compreasiom plates and milling the head, four water leads were taken to the head to provide additional cooling, that in the block being static, and a Borg and Beck clutch with a positive-action cluch-brake was fitted. A Sunbeam Twenty steering box was deemed an improventent on the original box.
An imposing one-piece two-seater body was hand-beaten in unpainted 18-gauge alloy, the sole framework for the panels being a tubular scuttle rail, as on the "J2" Allard, a 16-gauge engine bulkhead and a double wall behind the seats. Body and wings can be removed in 25 minutes, leaving all services, inducting the individual lamp-circuits, intact on the chassis. Gallay made a special radiator to blend with the body lines. A 22-gallon fuel tank is carried at the rear, feed being by twin electric pumps on the engine bulkhead. Two 6v. batteries live under the seats, and there is a full-length undertray.
Chevell started racing the car in 1949, and towards the end of the season triple d.d. Solex carburetters were fitted, on beautifully-contrived manifolds, together with all easy-flow exhaust system, a smaller ex-Hornet dynamo, a water-pump from a Rolls-Royce aero-engine and Firefly coil ignition in place of the previous dual ignition. Oil pressure was increased by "splicing on" a second oil pump below the original. The 1/2-elliptic rear springs were replaced by 1/4-elliptics, which materially improved rear wheel adhesion due to a happier sprung/unsprung weight ratio. This was felt to he desirable following a pirouette at the Blandford Hill-Climb: The springs are Talbot 105, minus five leaves each, anchored on a wide spring base adjacent to a tubular cross-member which offsets the tendency of the rather thin side-members to flex under suspension loads. The wheelbase was retained at 9 ft.
The wheels were converted to 18 in. and the axle-ratio raised to 4.1 to 1, using a Speed Twenty-Five crown and pinion, which neccessitated boring out the Speed Twenty nose-piece 3.8 mm.
The Alvis was raced in this form until July, 1950, after which Chevell acquired a 4.3-litre Alvis engine from an R.A.F. armoured car, many of which apparently went to Russia. This has the same dimensions (92 by 110 mm, 4,387 c.c.) as the car engine, and dry-sump lubrication by triple pump. Triple Solex d.d. carburetters and the R-R water pump, with six-branch feed to the head, were fitled, the head milled to give a compression-ratio of 8.25 to 1, an all-synchro Silver Crest unit gearbox adapted to this engine, together with a special multi-plate clutch and an 11 in. dia. flywheel, and it was then mounted in the chassis, lower than the Speed Twenty unit. (There had been a plot to an all-independant, short, light chassis for it, but time proved the enemy.) The crankshaft damper is dispensed with and a new Hardy Spicer propeller shaft was installed, running uphill to the axle. The old dynamo is retained, mounted forward, an exhaust, system with "bunches of bananas" manifolds and dual tail pipe with Burgess-type silencers was made up, the frame boxed-in for a quarter of its Iength at the front and the steering-ratio raised, on the advice of John Heath, from one-turn to 1 3/4-turns lock-to-lock, by milling from the solid a shorter drop-arm. Oil is carried in a three-gallon Gallay tank beneath the passenger's seat. The starter is 2-litre Lagonila, facing forward on to the flywheel ring. The camshaft, standard, gives an overlap of 30˚.
To suit the 4.3 engine a 3.8 to 1 axle ratio from a 4.3 tourer is used. With 7.00-18 rear tyres this represents 24.6 m.p.h. per 1,000 r.p.m. In top, and 4,500 r.p.m. have been reached on this ratio, so that the Alvis is capable of a genuine maximum of over 110 m.p.h. Road-equipped, over 4,000 r.p.m. is attainable, or approximately 100 m.p.h. The engine runs happily on straight Pool, giving 16-17 m.p.g. on the road, and in this form made fastest sports-car time at Gosport, beating Gale's Darracq. Third gear gives a maximum of about 80 m.p.h. and, with a dry weight of one ton and very low head resistance, the acceleration is immense, right from crawling gaits onwards. In sober fact, a s.s. quarter-mile occupies 15.85 sec. and the best Goodwood lap to date is 77.8 m.p.h.: 5.25-18 Dunlop tyres are used at the front, Dunlop Racing at the back. The shock-absorbers are PV6 Luvax-Girling at the front, mounted to take brake torque, Armatrong piston-type from is Ford 10 cwt, van at the back. Esso fuel, Lodge plugs and Sternoil oil are Chevell's favourites. The brakes are standard Alvis, drums lightened by drilling 18 3/4 in.-holes in them, and the wheel rims are drilled to obviate tyre creep. Cool air is taken to the carburetters by a scoop, but as the float chambers have not been balanced, this is normally blanked-off. Thrust races have been substituted for the king-pin thrust washers.
The steering wheel is quickly detachable, the instruments, including a Smith's rev.-counter driven from the side of the engine via the camshaft, are on a mottled alloy panel before the driver and water temperature is normally about 75° C., rising only in traffic blocks, the Gallay radiator designed for the Speed Twenty doing a good job for the 4.3 ! Oil pressure is around 20 lb./sq. in. and an oil-cooler may be incorporated later.
Chevell, a family man, whose wife enthuses over the AIvis, built the car as refaxation from running a garage business. It is very definitley a sport-car to be proud of!