We referred recently to what could be a 1906 grand prix Darracq engine, now installed in a suitable chassis. As the celebrations for the first grand prix, in France in 1906, approach, the question arises of which type of Darracq this engine was originally installed in. The 1906 GP cars were of 12,711cc (170 x 140mm), but the engine in question has a bore of 180mm, suggesting it was from one of the 1907 Darracqs, which had a stroke of 150mm (15,268cc). There was a suggestion that this engine in New Zealand came from Malcolm Campbell’s Darracq ‘Blue bird’ which he raced at Brooklands in 1912, but in fact this had an engine of 150 x140 (10,567cc).
Otherwise the enormous engine conforms, with bi-cylinder blocks and push-rod-operated overhead valves, described as having three valve seats as on the Hornsted Blitzen Benz. The total-loss lubricating system has been converted to pump-and-jet feed. A new carburettor had to be made to feed the inlet manifold, round which copper tubes were wound to improve cold starting. A crack in the crankcase had to be plated, but the bearings and con rods did not require replacement, though new piston rings were made.
The correct gilled-tube sharply veed radiator with a curved top cover is as on a 1906 GP Darracq. The engine has been put into a lengthened Darracq chassis with new side members — the production chassis had a wheelbase 2in shorter than that of those racing cars.
A production four-speed gearbox was used instead of the three-speed one on the racing cars, which required the engine to be an inch forward, with an 18in propshaft. For road use it was thought desirable to have a back axle with a differential. Where necessary, items such as spring hangers and front cross member were copied from the GP cars. An Albion lorry yielded a 1.5 to 1 crown and pinion for the differential, and a great many parts had to be replaced, such as all the gearbox pinions and the transmission brake shoes. The body was based on the Vanderbilt Darracqs, with just two bucket seats and a bolster tank behind, with nothing between the driver and the foot pedals, reminiscent of the famous 1905 200hp Darracq. Unusually, the radiator tank is beneath the driver’s seat, with pump feed, this and the fuel tank being of 3mm aluminium. The wheels on the car as bought were centre-lock American 24in items, which were retained but respoked to the original pattern.
Anne Thomson drove her car with determination at the Stope vintage car event at Ruapuna Park, Christchurch in February. How the Darracq first got to New Zealand is not known. A former owner of the engine was Bill Clark, when it was on the premises of the Hampton Tyre company in Christchurch in the late 1950s, before which the Star newspaper used it to drive a standby generator. The rebuilding of what does appear to have a 1907 GP engine in a reasonably correct replica chassis might or might not be welcome at any centenary of the first French GP which may be arranged.