The BMW M40 is an SOHC straight-four petrol engine which was produced from 1987 to 1994. It served as BMW's base model four-cylinder engine and was produced alongside the higher performance BMW M42 DOHC four-cylinder engine from 1989 onwards.
Compared with its M10 predecessor, the M40 uses a belt-driven camshaft, and hydraulic tappets. Like the M10, the M40 uses an iron block and an aluminium head. Fuel injection for the E30 versions is Bosch Motronic 1.3, and the E36 versions use Bosch Motronic 1.7.
Following the introduction of the BMW M43 engine in 1991, the M40 began to be phased out.
Versions Version DisplacementPowerTorqueYearM40B16- E30 version at 5,500 rpm at 4,250 rpm 1987M40B16- E36 version at 5,500 rpm at 4,250 rpm 1991M40B18- E30 version at 5,500 rpm at 4,250 rpm1987M40B18- E36 version at 5,500 rpm at 4,250 rpm 1991
M40B16 The M40B16 is a version of the M40, which has a bore of and a stroke of . It produces and .
Applications: 1988–1994 316i (E30) 1990–1994 316i (E36) 1992–1993 Bertone Freeclimber 2
M40B18 The M40B18 is a version of the M40, which has a bore of and a stroke of . It produces and .
Applications: 1987–1994 318i (E30) 1992–1993 318i (E36) 1989-1994 518i (E34)
See also List of BMW engines
References