Improving on Le Patron
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Today a Bugatti is an object of reverence, but it was not always so, as WB demonstrates with this much-altered example
The Bugatti was one of the foremost sports cars from 1909, and most of those who owned them were content with these very delectable cars in standard form. However, a few owners had the audacity to make changes to the specifications of these cars. For instance, one example was Mr F J Fielding and his Berk-blown Type 37 Grand Prix. The many alterations covered a larger supercharger, Exide accumulator in the tail, and an Ironclad coil. Other changes included a revised braking system and wire wheels, while two Solex carburettors were tried but eventually one sufficed. A new inlet manifold was also adopted. The cylinders were re-bored out to 69.5mm and the crankshaft rebalanced, new con-rods were fitted, four high-compression pistons used and the battery was moved to under the driver’s seat. The original petrol tank was divided into two, a Bosch dynamo replaced the Ducellier one, and a Berk three-bladed twin-rotor Roots-type supercharger was used, which was said to have come from one of the 1½-litre Thomas-Specials.
A new Laystall crankshaft was made and gears were provided to drive the supercharger, which could be put out of gear. It drew from a carburettor with 1-7/8 inch choke and a Smith’s vapour-spray easy starter, via a two-branch induction pipe arranged with central poppet-pattern blow-off valve. A pressure gauge was fitted. The supercharger lubrication was arranged by means of a ¼in lead from a T-shaped connection on the crankcase, stop-cocks being fitted for control. This lead played onto the supercharger drive and the supercharger rotor gears via jets and was driven via spiral pinions.
The coil ignition was replaced by a special FU4 Bosch magneto. A new cylinder block was manufactured, with modified valve seats and two plugs per cylinder. Special first and second gears were made and a new oil pump fitted giving 80lbs pressure. The thicker exhaust valves used Ubas valve caps all round and heavier blow-off valves in a gunmetal cage and stronger springs. A regulator valve was made for the cam box oil supply. New crown wheel and pinion were of NCCHKE steel. Elsewhere, 19-inch rear wheels and a 14/54 axle ratio were part of the non-standard changes. Other improvements to the front hubs and springs gave better road-holding.
In 1933-4 a Jeavons 4.66-2-1 rear axle was fitted and a gearbox arranged at the rear of the cambox to drive dual Scintilla Vertex magnetos, set horizontally. A Benton and Stone 203 petrol-dope two-way and a type 18a tap for the air were added. Jeavon’s own-designed pistons were incorporated, along with sprint camshaft, with high lift, and unusual firing order operating via longer rockers. Front suspension was modified and 3-litre brakes employed. After blowing up at a Chalfont hillclimb, due to fatigue in No3 con-rod, new H-section rods were made, in 80-ton steel, with Napier white metal run directly onto a cadmium base. These rods were 5mm longer than the previous ones.
Fielding was a real enthusiast, doing much work on his car himself, all for the sake of less than a minute of motoring against the clock, and that not exactly being guaranteed.