Last month we made our usual beginning-of-the-season visit to Cooper’s Garage at Surbiton and found the production of Cooper-Specials in full swing, as usual. Two Cooper 500s were ready for shipment to Finland, another for Norway, a couple for Germany, two for Switzerland and one for New Zealand—racing-car export with a vengeance.
Symonds will race a Cooper 500 this year, while Cooper 1,000s will be used by Betty Haig, Rogers and other newcomers, four of these cars having been sent to Australia recently. The exciting new 1,100-c.c. J.A.P. racing V-twins. when they come to hand, are scheduled for the Coopers of L. Leonard, H. Schell, Bradnack, Logan, Hartwell and a Swiss driver. John Cooper himself will rare a Cooper 1,100.
No alterations have been deemed necessary to the Cooper chassis for 1950 beyond a slight saving in weight, longer Hardy-Spicer universals and the fitting to all cars of the comfortable bucket-seat and magnesium-alloy wheels. Lockheed 2LS brakes are available front and rear and are being ordered by most drivers. Twin master cylinders are used, the brake fluid being contained in a tiny GaIlay two-compartment tank above them. The chassis is made in two lengths, 500 c.c. and “1,000” or “1,100.”
An ingenious development is the supply of two-wheel trailers to accommodate a Cooper, these trailers using the same wheels, tyres and brakes as the racer, thereby providing spares. They have ½-elliptic suspension and cost £65 each.
Burman gearboxes will be supplied where possible with the 1,100-c.c. engine, although a Norton box is used in Cooper’s own car. Apart from the racing single-seaters, some remarkably interesting sports two-seater Coopers are under construction.
The original Vauxhall Twelve-engined car still exists and the engine has been somewhat gingered-up. At Surbiton, too, we inspected a similar car with a “TC” M.G. Midget power unit. The chassis is that of a normal Cooper 1,000 with 2LS brakes all round, the two-seater light-alloy sports body being mounted on tubular cross-members. The engine, placed conventionally ahead of the driver, has a special head devised by J. Lucas, of Chessington, with larger valves than standard, two 1½-in. S.U. carburetters and a compression-ratio of 8.6 to 1. Mr. Lucas told its that 75 b.h.p. is delivered at 6,200 r.p.m. A neat Gallay radiator behind the nose cowling looks after cooling and the fuel tank straddles the propeller shaft behind the seat. Rack-and-pinion steering is used, and the back axle incorporates an E.N.V. nose-piece and has a ratio of 4 to 1, and the Cooper i.r.s. Cooper hopes that the weight of this attractive little car should be under 10 cwt. and the performance available should certainly be very interesting. The mudguards are attached to the body, whereas those of the Vauxhall-engined car pivot with the front wheels. Another two-seater sports car in course of construction followed the lines of this M.G.-engined Cooper, but had an air-cooled Sunbeam S7 vertical-twin 500-c.c. motor-cycle engine. In this case a 5-to-1 axle ratio is employed.
We believe that there is a project on the drawing-board for combining a gearbox with the crankcase of the 1,100-c.c. J.A.P. engine, so that it can be mounted transversely in the chassis and used with shaft-drive.
Leaving this centre of activity at Surbiton we journeyed to Guildford to have a look at Coombes’ Rover-engined Cooper sports two-seater, which is to be raced at Goodwood and elsewhere. A four-cylinder Rover engine has been reduced to under 1,100 c.c. by using rather drastic cylinder liners 5/32-in. thick. The standard crankshaft has been highly polished all over, the rods buffed, and the flywheel reduced in weight from 31½ lb. to 14 lb. Martlet pistons are used, which, with a copper gasket, give a compression ratio of 8½ to 1. The cylinder lead has enlarged inlet ports and oversize inlet valves of 1 15/32 in. diameter. Electric petrol feed is now used, it dural plate covering the aperture in the crankcase where the old camshaft pump bolted on. Dural cover plates replace the sheet-metal tappet covers, although a slight increase in weight has resulted here. Normal inner valve springs are used but the outer springs are considerably stronger than standard. Timing wheels and camshaft are normal Rover but a drive or a rev.-counter is taken from the end of the camshaft. A normal Rover water-impeller is retained, with its outlet pipe adapted to suit a low Gallay radiator of the type on the M.G.-Cooper. All moving parts of the engine have been very carefully assembled and R.R.34 bearing metal is used. Shell oil will be used.
Some difficulty was experienced in inserting this engine in the Cooper chassis, but this was overcome by removing the Rover starter housing from the clutch casing and mounting a Ford Eight starter on a plate bolted to the opposite, or near, side of the engine. The starter works quite effectively, driving through a larger than normal flywheel ring, and considerable weight is saved. To ensure a low bonnet line the twin downdraught carburetters formerly evolved have been replaced by two 1¼-in. horizontal S.U.s, on a fabricated manifold with four separate exhaust outlets converging to meet the exhaust pipe.
A Ford belt-driven dynamo is used, on the off side at the front of the engine. Two 14-gauge steel brackets support the front of the engine, with rubber mountings at the rear. The standard Rover gearbox is retained, but the free-wheel mechanism has been scrapped, with a useful reduction in weight; indeed, the box now weighs only about 45 to 50 lb. The rear axle is normal Cooper, with the E.N.V. nose-piece, the axle ratio being 4.5 to 1.
Another Cooper sports car, hailing from the Windsor area, has a Jowett Javelin power unit.