The TVR Speed Twelve engine is the name of a

V12 engine A V12 engine is a twelve-cylinder piston engine where two banks of six cylinders are arranged in a V configuration around a common crankshaft. V12 engines are more common than V10 engines. However, they are less common than V8 engines. The fi ...

manufactured by TVR for use in the TVR Speed 12 race car, and later the TVR Cerbera Speed Twelve road car. The engine was developed by essentially joining two Speed Six engine blocks to a common crankshaft. However it featured a revised cylinder head design with bucket valve actuation in place of the Speed Six's finger follower system. The completed engine displaced 7.7 litres and was originally developed for racing applications in TVR's Speed Twelve. Later on, a version was developed for the prototype of a road car to be called the Cerbera Speed Twelve. Unusually for an automobile, the Speed Twelve's engine block was not constructed of

cast iron Cast iron is a class of iron–carbon alloys with a carbon content more than 2%. Its usefulness derives from its relatively low melting temperature. The alloy constituents affect its color when fractured: white cast iron has carbide impuriti ...

aluminum Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. It has ...

alloy An alloy is a mixture of chemical elements of which at least one is a metal. Unlike chemical compounds with metallic bases, an alloy will retain all the properties of a metal in the resulting material, such as electrical conductivity, ductility, ...

, but rather of

steel Steel is an alloy made up of iron with added carbon to improve its strength and fracture resistance compared to other forms of iron. Many other elements may be present or added. Stainless steels that are corrosion- and oxidation-resistant ty ...

. The racing version of the engine produced approximately with its power limited by the intake restrictors required by racing regulations. For the road-version of the engine, the restrictors were not needed so the engine was developed without them. According to reports from TVR engineers, the de-restricted engine snapped the central shaft of their -rated

dynamometer A dynamometer or "dyno" for short, is a device for simultaneously measuring the torque and rotational speed (RPM) of an engine, motor or other rotating prime mover so that its instantaneous power may be calculated, and usually displayed by the ...

during the bench-test. The engine's output was later estimated at , though the official figure given by TVR was . When the prototype vehicle was road-tested by then-owner Peter Wheeler, he reportedly concluded that the vehicle was too powerful to be practical and the project was scrapped.

References

{{DEFAULTSORT:Tvr Speed Twelve Engine Twelve V12 engines