| BL O-series | |
|---|---|
 | |
| Overview | |
| Manufacturer | British Leyland Motor Corporation Austin Rover Group |
| Also called | Rover M8 |
| Production | 1978–1993 |
| Layout | |
| Configuration | Straight-4 |
| Cylinder block material | cast iron |
| Cylinder head material | aluminium |
| Valvetrain | SOHC |
| Combustion | |
| Fuel system | Carburettor or Fuel Injection |
| Fuel type | petrol |
| Cooling system | water-cooled |
| Chronology | |
| Predecessor | |
| Successor | |
The BL O-series engine is an automobile straight-four engine family that was produced by the Austin-Morris division of British Leyland (BL) as a development of the BMC B-series engine family. (See also another B-series successor, the BMC E-series engine.)
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.