Introduced by BL in 1978 in the rear wheel drive Series 3 Morris Marina and the smaller engined versions of the front-wheel-drive Princess, it was intended to replace the 1.8 L B-series unit.

The main advance over the B series was that the new unit was of belt driven overhead camshaft configuration, with an aluminium cylinder head.

Offered in the unusual capacity of 1.7 L as well as 2.0 L, it proved to be reliable and was widely used in BL vehicles.

This installation of the O-series was adapted for use with the Honda PG-1 end-on manual gearbox, replacing the gearbox-in-sump design traditionally used on British Leyland front-wheel-drive products.

The cylinder blocks of the transmission-in-sump (Princess/Ambassador), rear wheel drive longitudinal (Marina/Ital/Rover SD1), and the transverse, end-on transmission (Maestro/Montego/Rover 800) versions are not interchangeable.

The oil-burning versions, known as the Rover MDi or Perkins Prima, proved to be highly successful in the Maestro and Montego, and helped sustain the ailing mid-sized models into the 1990s.

Perkins successfully marketed the engine under its own brand in the industrial and marine sectors.