BMW Engine Codes

You may come across many acronyms and short hand "codes" while shopping for parts for your BMW. The BMW E-chassis and F-chassis codes are obvious. But another code refers to the type of engine used in your BMW. BMW engines evolve from one generation to the next but generally derive from one original design. For example, the inline-6 cylinder engines in the E34, E36, E39, E46, E53, Z3 and Z4 can all trace their origin to the M50 introduced in 1991. With revisions and updates over the years it's unlikely that parts will simply interchange so knowing the specific engine type can be very helpful when sourcing parts. BMW has gone through several variations on the engine designations; from the 1960s to the 2000s they had the "M" engine family (not to be confused with BMW Motorsport); from the 2000s-2010s they had an N engine code; from the mid 2010s they have a new modular B engine family. Below are charts detailing the BMW engine family codes with a handy de-coder image so you know how each code is broken down. We concentrated on engines used in the US market, as well as BMW Motorsport production (S code) and racing (P code) engines.

This list is some of the more common engine code designations that a US enthusiast may encounter. Engines may change from one type to another based on different factors, including model year and even geographical region. This list includes the engine code, number of cylinders, engine size, the BMW models it's typically found in, and other important information. We have intentionally left off engines not commonly available or known to the US market.

M Code (1964-2006) Regular Production Engines
Engine Code Engine Size (liters) # of Cylinders
and layout
# of Valves Camshaft and Valve Timing HP Rating Torque Rating Active Years Example Models Features
M10 1.6, 1.8, 2.0 I4 8 SOHC 98-104 104-107 1964-1985 2002, E21 320i, E30 318i M31 turbo version = 168hp
M20 2.0-2.7 I6 12 SOHC 121-168 120-180 1983-1992 E21 323i, E30 325e, E30 325i, E34 525i M20B25 = 325i engine
M20B27 = 325e engine
M21 2.4 I6 12 SOHC 84-114 112-162 1983-1985 524td turbo diesel
M30 2.5-3.5 I6 12 SOHC 175-208 159-225 1968-1993 E9 2800, E24 633CSi, E28 535i, E34 535i carburetor up to 1975;
1982-1988: 3.4L 8.0:1 compression
1988-1989: 3.5L 9.0:1 compression
M40 1.6, 1.8 I4 8 SOHC 102-113 104-120 1987-1991 E30 318i Euro models
M42 1.8 I4 16 DOHC 138 129 1988-1995 E30 318is, E36 318i, E36 318ti S42B20 used in BTCC racing
M44 1.9 I4 16 DOHC 138 133 1996-1999 E36 318ti, Z3 1.9 US OBD-II models