RUMBLINGS, November 1950

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RUMBLINGS

In the Ulster Trophy Race last August the second fastest lap was put up by a .I.P. powered with a 998-e.e. V-twin Vincent11.11.1). engine, which went round at 73.84 A New m.p.h. in the wet. The product of Racing Car Joseph Potts, Ltd., of BelIshii’, Lanarkshire,

is about to go into production. The makers stale that II ley will endeavour to offer a racing car suitable for tlu, installation of 500 c.c., 1,000 C.C. or 1,100 e.c. motor-cyclet pe engines at a price within the react% of many enthusiasts. It is hoped to have these ears ready for next season, and in 300-c.c. form I he J.P. will coutply wit it Formula 111 reqiiirements. The itas a simple tubular frame with tw(t steel tubes Parallel on each side, braced and cross-braced to give it very rigid structure, and cum tained at each end in fabric:deli steel

housings that. act as mountings for the transverse leaf springs of the wishbone, all rotund independent suspension, the rear housing also carrying the back axle in self-aligning bearings. A light alloy steering-box houses rack-and-pinion Steering. the brakes are 8-in. diameter Lockheed Ityllraufic. with 2ES at the front, cable actuation being confined to the hand lever, which c(meerns the rear wheels. Girling doulde-acting, struttype shuck-absorbers are litted ; the wheels arc Of east elekt rout, with integral brake drums. They curry 4.00 13 front and 3.00-15 rear tyres. %Vhichever engine is installed. the drive goes by heavy-duty primary chain to it T.T. Albion four-speed motor-cycle gearbox and frean there to the back axle by another chain. Ishe back axle incorporates universally-j(linted driving shafts. TILV CI /Ili ml pedals in the cockpit are adjustable to suit different drivers and a large rev.-counter is positioned centrally. Tlw body is a singleseater in aluminium alloy sheeting on a framework integral with the chassis and consisting of a steel tirewall and steel hoops of angle and strip steel, strongly interbraced. The finish is cellulose tO any colour to choice, the Itunlopillo seat is [mule to individual size requirements, there is a Perspex racing semen, and a lightweight three-spoke steering wheel. The foci system comp ises double tanks of approximately 10 gallons capacity, feed being by gravity and haunt-pump, the latter for the long-range tank. The .LP. has a wheelbase of 7 rt. 3 in., a front track iif 3 0. 11

and a rear track of 3 ft. 7/ in., and its weight, iii raeing trim with 500-e.e. J.A.P. engine and long-range tanks, is given as 835 lb. The price in this t rim, less engine, will be 2525. Engines are to be supplied at makers’ list prices :tad fitted at no extra charge. This sounds like a proposition worth investigating and we shall be interested to see how many .I.P.s come to the starting-grids next year. • • Another new racing car, and one which has already made its debut at Castle Coti li a’ 011 October 7t Ii when, driven by !Kenneth McAlpine, it finished second to

And Another Moss’ 2-litre two-seater 11.W.M. in the 11 21-litre racing car scratch race, is the Formula II Connaught. The smart, conliact appearanee of this single-seater (701ln:ought pleased the connoisseurs. The car has it tubular chassis with a wheelbase of 7 ft.. and a -front trawl( of 3 ft. 101 in., the rear traek being 4 ft. 01 in. Suspension front and baek is independent, using wishbones and torsion bars. and giving 311 per cent. progression at full bumps. The roll centre is 4 in at the front, Siitt. at Lite back, and with all fluids and driver 471 per cent, of the total weight is borne by the front wheels, 521 per cent. by the back:wheels. This exeellent, almost 40/50 weight distribution is achieved by using twin tanks, with a total capacity of 191 gallons, one on each side of the chassis-. When these tanks are empty the weight. distribution is t8a per cent./ 511 per cent. front-rear. Fifteen-inch cast-elektron disc wheels carry Dunlop racing tyres, 5.50 by 15 at the front, 6.0 by IS at tlw back. Braking is Lockheed 21,5 hydraulie. using /2 by 2 M. Alibi bonded brake drums ‘t’lti’. scienti(icallydesigned chassis has rack-and-oinion steering with a ratio calling hit. IA limns of the steering wheel from lock to loek and

Providillg it turtling eirelc of aPProximalelY 41) ft. The engine, like that in the sporus Connaught , is a 73 by 100 inns. -1,707-e.c. Lea-Frauds unit with the well-known 90 Ilrgrees inclined overlWad Valves tiperated by Ow Lea-Franck !talent high-set CilMAII:liftS and stunt p1511-rods. Carburation is by a !D TA’. Antal carburetter to each cylinder and the sparks: are manufactured by it Scintilla NV4 magneto. The lubrication system carries 31 gallons ()I’ oil. The drive passes from the enghle RI an Armstrong-Siddeley preseleetor gearbox having rathis of 1. 1,211, 1.505 and 2.014 to I. Behind this gearbox is a transfer box which can provide live alternative axle ratios, which can be

changed in under 30 mitudes. A normal differential is used, but a ZE can be fitted if reiplired.

Tlw engine is giving 139 1.).11.1). at 0,000 r. mu on the comparatively modest compresshin ratio of 8.75 to 1. Fuel feed is by an engine-driven air pump supplemented by a band pump. This Formula II Connaught weighs 10 8 cwt. dry and 14.3 ewt. ready fin. racing. The frontal area is 9.A sq. ft. At Castle Combe the car was run as part of Connaught Engineering’s development programme and MeA !pine and Clarke must feel Very I Willi Wit the excellent showi»g put up by a car they still regard as in the mithile of prototype devehipment. It was actually finished last Angtst but sustained a crash avoiding hay-mak i tn.! malltinery while being tested at Silversttune (what, 110 Itrooklands ?) and this. set lite scheme back. only 40 miles of prototype-testing and 60 milesof practiee had been

run prior to the Castle Combe meeting. Incidentally. Connauglit Engineering of Send, Surrey, have the single-seater ill production the basic price being 22,0410.

Next year Formula II racing will be enhanced by this interesting newcomer ‘Vhielt organiser will be the first to give us a long Formula Ii race in this country ? With the possibility of an unblown 2-10.0• Formula I in 1952 this sort ld raving, for which British ears like this Connaught, the 11.W.M., and the Cooper are eminently suited. backed by a number of excellent. private-owner ears. ‘mist be given greater prominence in England. Pin taps the MAMA% will give us a long-distance Formula 11 race t,t Goodwood. The number of enthusiasts engaged in building Austin Sevens to the 750 Club Formula is legion and so is the number of trials and other specials gaining urge from the Urge via installation of mildly-tuned Ford Ten power units in lightweight chassis. The Nuffield

organisation, too, can claim its enthusiastadherents. Apart from its own sensible ” tuning-stages ” applicable to the current ” TD ” M.G. Midget,. some interesting facts about the M.G. successfully raced by IL W. Jacobs–he was placed third in the Mozott Srowr Brooklands Memorial Trophy contest—were divulged during a talk lie gave sometime ago to the NVest Essex C.C.

After satisfactory experience in competition events with a ” TC ” M.G. Midget, Jacobs started, in August, 1948, to evelve his present car. He used a ” ‘1’A ” M.G. chassis, as the sliding trunnions for the road springs were considered to give better roadholding than the shackled springs of the —IC.” The engine is a hybrid, with a Morris Ten cylinder block linered down from 63.5 to 62 min. bore, to give a capacity of 1,086 c.c. The cranksluift is also Morris Ten, balanced and shotblasted. Flywheel and timing sprockets were lightened and ” TC ” M.G. connecting-rods installed. The Morris valve gear was used unmodified and a compression-ratio of 8 to was achieved by using special Martlet pistons. The clutch was Morris, with M.G. clutch springs. All these ” bits ” with the exception of the pistons can be bought from any Morris dealer. At first a special inlet manifold and separate off-take exhaust system were. used, in conjunction with twin-downdraught 14/56 Wolseley S.U. carburetters, and the gearbox was Morris. Seeking more urge, ,Jacobs fitted a belt-driven Marshall supercharger on the near side of the engine where the dynamo normally lives and replaced the Morris box with a close-ratio box from a ” TC “

The blower pressure is 18 lb.;sq. in., and the engine rums up to 7,000 r.p.m.

The back axle is M.G., the front axle likewise M.G., but with NVolseley Hornet brakes ; 17-in, front wheels are used and Rotollo shock-absorbers were eventually discarded in favour of Newton struts.

In two seasons’ racing the sole troubles were a broken valve and loss of blower belts, and out of 14 ” starts ” in sports-car races Jacobs won seven times. His M.G. has lapped the Silverstone club circuit at 74.14 m.p.h.

News of another Nuffield-base special comes from our contemporary Australian Motor Sports. It concerns Alan Gercken’s 1938 Morris Eight tourer, which proved too sluggish to be altogether pleasing in the hill-country, especially where passing is difficult for miles on end. So Gereken persuaded the Spit Hill Garage at Mosman to install a Jeep power unit. The beauty of the thing is that it went in without necessitating any external alterations to betray its presence. The Jeep dynamo was retained and, for a while, the original 5.3 to 1 back axle. Later a cunning overdrive, made up from Harley-Davidson sprockets and primary chain, was built. in, and a Morris Utility crown and pinion installed in the original back axle. Also, 6.00 by 16 tyres grace the back wheels. This gives overall gear-ratios of 10.3, 6.1 and 3.9 to 1, and at 4,500 r.p.m. the innocent-looking Morris Eight does 32, 54 and 85 m.p.h., respectively. The 2-litre Jeep engine, you see, gives 60 h.p., or 86 b.h.p. per ton when installed in a Morris Eight. During a 1,600-mile trip from Sydney to Brisbane and back towing a 30-cwt. caravan, the fuel consumption averaged 24 m.p.g., cruising at 60 in.p.h., which is equal to 3,000 r.p.m., and 2,330 f.p.m. piston speed. Our contemporary refers to this Morris as ” a perfect trap for TC’s ” Fun !

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