BMW M40

The BMW M40 is an SOHC straight-four petrol engine which was produced from 1987–1994.^[1][2] 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.

BMW M40 engine
Overview
Manufacturer	BMW
Production	1987–1994
Layout
Configuration	Naturally aspirated straight-4
Displacement	1.6 L (1,596 cc) 1.8 L (1,796 cc)
Cylinder bore	84 mm (3.31 in)
Piston stroke	72 mm (2.83 in) 81 mm (3.19 in)
Cylinder block material	Cast iron
Cylinder head material	Aluminium
Valvetrain	SOHC
Combustion
Fuel system	Fuel injection
Management	Bosch Motronic 1.3 or 1.7
Fuel type	Petrol
Cooling system	Water cooled
Chronology
Predecessor	BMW M10
Successor	BMW M43

Compared with its M10 predecessor, the M40 uses a belt-driven camshaft,^[3] 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,^[4] and the E36 versions use Bosch Motronic 1.7.^[5][6]

Following the introduction of the BMW M43 engine in 1991, the M40 began to be phased out.

Versions

Version	Displacement	Power	Torque	Year
M40B16- E30 version	1,596 cc (97.4 cu in)	73 kW (99 PS; 98 hp) at 5,500 rpm	141 N⋅m (104 lb⋅ft) at 4,250 rpm	1987
M40B16- E36 version		75 kW (102 PS; 101 hp) at 5,500 rpm	143 N⋅m (105 lb⋅ft) at 4,250 rpm	1991
M40B18- E30 version	1,796 cc (109.6 cu in)	83 kW (113 PS; 111 hp) at 5,500 rpm	162 N⋅m (119 lb⋅ft) at 4,250 rpm	1987
M40B18- E36 version		85 kW (116 PS; 114 hp) at 5,500 rpm	165 N⋅m (122 lb⋅ft) at 4,250 rpm	1991

M40B16

The M40B16 is a 1,596 cc (97.4 cu in) version of the M40, which has a bore of 84 mm (3.3 in) and a stroke of 72 mm (2.8 in).^[7] It produces 73 kW (98 hp) and 142 N⋅m (105 lb⋅ft).^[8]

Applications:

• 1988–1994 316i (E30)
• 1990–1994 316i (E36)
• 1992–1993 Bertone Freeclimber 2

M40B18

The M40B18 is a 1,796 cc (109.6 cu in) version of the M40, which has a bore of 84 mm (3.3 in) and a stroke of 81 mm (3.2 in).^[7] It produces 83 kW (113 PS) and 163 N⋅m (120 lb⋅ft).^[6]

Applications:

• 1987–1994 318i (E30)
• 1992–1993 318i (E36)
• 1989-1994 518i (E34)

See also

• List of BMW engines