M5x

The BMW M5x range of engines are a line of 6-cylinder engines, fitted to BMW models between 1991 and 2001. The range is comprised of three main units; the M50, M50TU and the M52. All M5x engines are fundamentally based on the M20 engine that powered the E30 320i, 323i and 325i, and are therefore very popular engine swaps.

Versions

Models

Engine	Displacement	Power	Torque	Redline	Year
M40B16	1.6 L (1596 cc/97 in³)	75 kW (101 hp) @ 5500	143 N·m (105 ft·lbf) @ 4250	6200	1988
		73 kW (98 hp) @ 5500	141 N·m (104 ft·lbf) @ 4250	6200	1988
M40B18	1.8 L (1796 cc/109 in³)	85 kW (114 hp) @ 5500	165 N·m (122 ft·lbf) @ 4250	6200	1987
		83 kW (111 hp) @ 5500	162 N·m (119 ft·lbf) @ 4250	6200	1987

Components

Head

Rocker Cover

Despite the three styles of Head, the rocker cover is interchangeable across all M40 engines. It is positioned on 8 studs and fixed with M10 nuts. It has one hole for the Oil Cap, and one port for the breather hose.

When removing and replacing the rocker cover, it is worth replacing the rocker cover gasket.

Breather Hose

To balance the pressure inside the head, a rubber hose runs from the top of the rocker cover to the throttle body.

Servicing

Main article: Basic M5x Servicing

See also

• Engines
• M10
• M42