A V12 engine is a V engine with 12 cylinders mounted on the crankcase in two banks of six cylinders, usually at a 60° angle to each other, but in some cases at a wider or narrower angle, with all 12 pistons driving a common crankshaft.
In automobiles, V12 engines have never been common due to their complexity and cost. They are used almost exclusively in expensive sports cars and luxury cars and are sought after for their power, relatively vibration-free operation and distinctive sound.
The first V12 was manufactured as a Craig Dorwald by Ailsa Craig in May 1904. 23,000cc, 150 bhp at 1000 rpm. Commander May used it successfully in the American races 1908. Being a hot coil engine, water inevitably shorted the high tension and the engine regularly misfired. This was cured with the introduction of two magnetos from Sir Robert Bosch.