Rover IOE straight-six engine

The Rover IOE straight-six was the six-cylinder inlet-over-exhaust engine of the Rover Company, with an overhead inlet valve and a side exhaust valve, an unusual layout that Rover carried over from the P4 to the P5. It powered the Rover 75 from 1949 as a 2.1-litre unit, enlarged to 2.2 litres in 1954, and in 1953 a larger 2.6-litre six of 90 hp went into the Rover 90, followed by the 105 with higher compression and the 100 with a seven-bearing short-stroke version of the P5 unit. The 110 used a Weslake cylinder head and produced 123 hp. For the P5 of 1958 Rover enlarged the engine to 2,995 cc, producing 115 bhp, by shifting the bore centres and moving to seven bearings. The 2.6-litre six also went into the long-wheelbase Series IIA and Series III Land Rovers. The three-litre unit was at the limit of its development, and the P5 later took the Buick-derived V8.