Rover P6 overhead-camshaft four-cylinder engine

The Rover P6 overhead-camshaft four-cylinder engine was the 1,978 cc unit designed specifically for the Rover 2000 saloon, announced in October 1963. It had a cast iron block with an aluminium cylinder head, five main bearings and a single overhead camshaft driven by a double roller chain, which Motor Sport called a departure from previous Rover practice at the car's launch. Its bore and stroke were identical at 85.7 mm, a deliberately square layout meant to hold down piston speeds and bearing loads at sustained motorway speeds, and the cylinder head was flat with the combustion chambers cast into the piston crowns, the arrangement sometimes called a Heron head. Launch output was 90 bhp net at 5,000 rpm on a single SU carburettor, and a twin-carburettor 2000 TC version followed in 1966. A bored-out 2,205 cc version with a 90.5 mm bore powered the 2200 models from 1973 until production ended in 1977. The engine was designed so that a Rover gas turbine could later fit the same engine bay, and the Buick-derived V8 took its place in the 3500.