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20

Sir,

Congratulations on your resolution to continue the publication of MOTOR SPORT, it will be the duty of all regular readers to see that this one light in the present darkness is not extinguished.

As an Austin enthusiast I was very interested in the article describing the ex-Chaplin Seven, now owned by Mr. Lush, but surely your thoughts must have been on the Continent when you state that the three-branch exhaust is on the off side I Possibly some readers might be interested in a brief description of my own somewhat special Austin, which, with its recent modifications, should have been appearing in competitions shortly. Starting life as a 1930 coupe, its body had been converted to a short open Chummy before it came into my possession in January, 1937. I commenced by completely stripping the whole job, every worn part was replaced, and every stressed bolt replaced by high tensile, nuts split-pinned and bolts drilled and wired. The engine work consisted of the usual overhaul, in addition to which ports were opened out and polished, trumpet exhaust valves of KE965 with double valve springs fitted, flywheel lightened and heavy clutch springs used. The dynamo was replaced by 1937 type with the centrifugal advance control

distributor head. A double fan pulley was machined, in order to drive, by springbelt, a revolution counter drive-wheel having it bearings in a casting mounted on the dynamo body itself. The cylinder head was an aluminium ” Alta ” and a special 1 gallon sump of sheet metal was used. Twin &U.’s, from a P type Midget were adapted, using short aluminium castings bolted to the standard exhaust manifold and incorporating a # inch diameter balance pipe.

All alterations to body and chassis were made with an eye to competition requirements, the more marked of these being the use of LMB front suspension with a very strong leaf spring, additional transverse Hartfords at rear, attached to reinforced chassis ends and to lugs mounted on the axle casing itself. A light enclosed remote gear control with short stubby gear lever was constructed for the three-speed box and a malleable steering-box substituted for the aluminium one already fitted.

The brakes were coupled by massive drop lever made from the solid, clamped to the brake operating cross tube and this, in conjunction with long brake cam levers and a 12 inch extension to the hand brake lever, provided fairly efficient stoppers.

A rear double spare wheel carrier of sufficient strength to withstand trials surfaces was not easy to accommodate, but this difficulty was surmounted, thereby providing more weight over the back axle where required. Off side door was cut down and Sorbo padded, a foldflat screen of brass section and twin aero screens were mounted, large ventilating doors in bonnet sides and top controlled the under under-bonnet temperature, wings of the fixed cycle type, very rigidly braced, have given no trouble, in fact the whole car may be lifted by them. The Brooklands silencer was mounted flat underneath the body on the near side, a suitable asbestos sheet fitted to the underside of the body prevented any undue rise in temperature of the passenger’s seat ; in order to avoid various components, the tail pipe presenting an appearance not unlike Sir Harry Lauder’s

famous walking stick. The radiator is standard 1980 except for a Monza snap filler. The whole car was cellulosed Brunswick green trimmed to match and with a green fabric all-over zipp tonneau-cover, umbrella pattern hood and passenger’s

side screen. Additional equipment includes double screen wipers, clock, oil pressure gauge, Nivex petrol gauge, radiator thermometer, Jaeger rev. counter and Zeiss headlamps. In April ’38 the car was completed and taken down to the Track for test ; on 130 x40 Michelin tyres and without passenger it held 4,200 r.p.m. round the Byfleet, approximately 70 m.p.h., the addition of a passenger reduced this speed

by 5 m.p.h. In the J.C.C. High Speed Trial in August ’38 it failed to attain the rather high standard speed set for the class, but averaged 52 m.p.h. with a maximum on the Railway Straight of 64 and was very definitely controllable through the bends, due, no doubt, to the LMB suspension.

At Beechwood Park in September, using 4.00 x 17 rear wheels and tyres and a light duralumin bonnet, which saved 11/ lbs., it reached 4,500 r.p.m. in second and gained second place in the 850 c.c. Sports Car Class. After the Cottingham Trial in November I replaced the standard 4.9 to 1 axle by a 5.25 Ulster axle and with further

lightening and using special 17 inch. car section wheels with 4.75 Freighters ran in the Bossom and C.L.J. Trophy trials gaining only experience in each, the car, though, giving no trouble whatever other than lack of urge, at times however, this lack allowed the car to complete some sections non-stop where other more potent vehicles dug themselvesin. Early this year, realising the fact that all really successful Austins are blown, the construction of another engine was put in hand. A 1929 crankcase was adapted to pressure feed in the usual way, a 1931 Ulster crank fitted, and steel conrods of KB used, another block wasprepared, ports opened out, polished, bored and fitted with Aerolite blown, Ulster pistons. As the crankcase was of the coil ignition type, it was intended. to use the unblown Ulster camshaft. but this was rejected as the distance of the pulley from the camshaft bearing would have caused a great strain to be thrown on this bearing, due to the tension load of the twin-blower drive belts ; so, by means of grinding small clearances on the centre pair of cams, centre roller bearing outer ring and the use of special diameter rollers, a high. lift Speedy camshaft was conjured into, the case. It was then, of course, necessary to use the Speedy pressure feed nose piece and steel timing gears. The standard tappet guides were turned down and solid tappets with hardened buttons made up to suit, the remainder of the valve gear being standard unblown Ulster. An early ” Brooklands ” head, copperplated, was lapped dead true and bolted down on a solid copper gasket by high tensile cylinder head studs. A steel double pulley keyed to the camshaft end provides the means for driving, by twin belts, a type ” 75 ” Marshall blower mounted on a inch plate steel platform supported on a gantrey level with the cylinder head and stayed to the studs, on the near side ; the blower pipe passes over the cylinder head and down into a ” 65 ” downdraught induction pipe, the usual blow-off valve being incorporated. The twin belts are tensioned by a special fan pulley, which jockeys on the back of the belts and carries a mag. ignition

type fan. The flywheel is extensively lightened and Ulster cast iron linings with heavy springs are used. As it was decided to use a four-speed box the fitting of this entailed the use of the old geared pattern starter and the shortening of the propeller shaft, so a 1938 Hardy-Spicer shaft was adapted and the tail shaft flange of the Ulster axle modified to take the H.S. joint. A well swept three-branch exhaust manifold was made up of sheet metal, beaten

and welded, with a inch plate port flange, the radiator header tank was trebled in capacity to cope with the increased heat flow in the blown engine.

There, for the moment, the job stands and such details as carburetter type and size, blower shaft extension, alterations to body, etc., must await the termination of the present unpleasantness, when the car should give a fairly good performance in trials and sporting events. I am, Yours etc.,

H. L. BIGGS. Putney, [We agree, “off side” should read near side as Mr. Biggs suggests.—Ed.] • Have you registered with your News agent or paid your Annual Subscription to 21 CITY ROAD, LONDON, E.C. I