Zenith Carburettor Company (British)

The Zenith Carburetter Company Limited was a British company making carburettors in Stanmore Middlesex, founded in 1912 as a subsidiary of the French Société du carburateur Zénith. In 1965, the company joined with its major pre-war rival Solex Carburettors, and over time, the Zenith brand name fell into disuse. The rights to the Zenith designs were owned by Solex UK (a daughter company of Solex in France).

While better known for its much later products, Zenith produced carburettors that were standard equipment on some early automobiles, for instance examples from the Edwardian era, including the Scripps-Booth.

Products

Zenith's best-known products were the Zenith-Stromberg carburettors used from 1965–1967 Humber Super Snipe V, 1967–1975 Jaguar E-types, Saab 99s, 90s and early 900s, 1969–1972 Volvo 140s and 164s, 1966–1979 Hillman Hunter and derivatives, 1970–1981 Hillman Avenger, North American spec MGBs and MG Midgets, and some 1960s and 1970s Triumphs.

The Triumph Spitfire used Zenith IV carburettors in the North American market. In Australia, the CD-150 and CDS-175 models were fitted to the high-performance, triple-carburettored Holden Torana GTR-XU1.

Designed and developed by Dennis Barbet (Standard Triumph) and Harry Cartwright (Zenith) to break SU's patents, the Stromberg carburettor features a variable venturi controlled by a piston. This piston has a long, tapered, conical metering rod (usually referred to as a "needle") that fits inside an orifice ("jet") that admits fuel into the airstream at the venturi of the carburettor. Since the needle is tapered, as it rises and falls, it opens and closes the opening in the jet, regulating the passage of fuel, so the movement of the piston controls the amount of fuel delivered, depending on engine demand.