BMW M10

The BMW M10 is a SOHC inline-4 petrol engine which was produced by BMW from 1962-1988. It was the company's first four-cylinder engine since the BMW 309 ended production in 1936 and was introduced in the New Class sedans.

The M10 was used in many BMW models, with over 3.5 million being produced during its 26 year production run.

The turbocharged BMW M12 engine— used in the Formula One racing— was based on the M10 engine block and produced up to 1400 PS in qualifying trim.

Following the introduction of the BMW M40 engine in 1987, the M10 began to be phased out.

Development
Baron Alex von Falkenhausen — an engineer and racing driver — designed the M10 in the late 1950s. He was asked by BMW to design an engine with a displacement of 1.3 L, but felt that this would be insufficient for the company's future needs. He convinced management that the minimum capacity should be 1.5 L, and offered an engine that could be expanded to a maximum of 2.0 L.

Design
The M10 has a cast iron block and an aluminum alloy head with hemispherical combustion chambers and two valves per cylinder. It features a forged crankshaft, counterbalance weights, five main bearings and a chain-driven camshaft.

The initial version of the M10 had a bore of 82 mm and a stroke of 71 mm, resulting in a displacement of 1499 cc. The peak power rating was 80 PS.

Naming conventions
The engine was initially known as the "M115" (the last two digits representing the 1.5–litre capacity). Over the years, variants of the engine were given various codes (most of them starting with "M1" and the remaining digits relating to the capacity). In 1975, the engine became known as then "M10", then in 1980 it was given the standardised BMW engine code of M10B18 (where "M10" represents the series, B represents petrol (Benzin in German) and the "18" represented its then 1.8–litre capacity).

The M115 and all related engines have become retroactively known as the "M10" family.

1499 cc engines
The M115 version has a displacement of 1499 cc and produces 55-60 kW. It has a bore of 82 mm and a stroke of 71 mm. Lower power models have a compression ratio of 8.0:1, while higher power models have a compressions ratio of 8.8:1. Fuel is supplied via a Solex 38 PDSI carburettor.

Applications:
 * 1962-1964 BMW 1500
 * 1975-1977 BMW 1502

1573 cc engines
The M116 version has a displacement of 1573 cc and produces 63-77 kW. It has a bore of 84 mm and a stroke of 71 mm. The standard specification has a compression ratio of 8.6:1 and uses a Solex 38 PDSI carburettor. The 1600 ti version has a compression ratio of 9.5:1 and uses twin Solex 40 PHH carburettors.

Applications:
 * 1964-1966 BMW 1600— 63 kW
 * 1966-1975 BMW 1600-2/1602— 63 kW
 * 1967-1968 BMW 1600 ti— 77 kW

The M41 version produces 90 PS, has an 8.3:1 compression ratio and fuel is supplied by a Solex 32 DIDTA carburettor.

Applications:
 * 1975-1980 E21 316

The M98 version produces 55 kW, has a compression ratio of 9.5:1 and uses a Pierburg 1B2 carburettor.

Applications:
 * 1981-1983 E21 315

1766 cc engines
The M10B18 version produces 90 - 105 PS, depending on specification. The bore is 89 mm and the stroke is 71 mm.

Applications:
 * 1969-1972 1800— 66 kW, 8.6:1 compression, Solex 36-40 PDSI carburettor
 * 1971-1975 1802— 66 kW, 8.6:1 compression, Solex 38 PDSI carburettor
 * 1980-1983 E21 320i/320is— U.S. only, 75 kW, 8.8:1 compression, Bosch K-Jetronic mechanical fuel injection
 * 1980-1983 E12 518— South Africa only, 77 kW, 10.0:1 compression, Bosch K-Jetronic mechanical fuel injection
 * 1982-1987 E30 316 — 66 kW, 9.5:1 compression, Pierburg 2BE carburettor, Ecotronic.
 * 1982-1988 E30 318i— 77 kW, 10.0:1 compression, Bosch L-Jetronic electronic fuel injection
 * 1981-1988 E28 518i— 77 kW, 9.5:1 compression, Bosch LE-Jetronic mechanical fuel injection.

1773 cc engines
The M118 version has a displacement of 1773 cc and produces 90 - 130 PS, depending on specification. The bore is 84 mm and the stroke is 80 mm.

Applications:
 * 1963-1968 1800— 66 kW, 8.6:1 compression, Solex 36-40 PDSI carburettor
 * 1963-1966 1800ti— 81 kW, 9.5:1 compression, twin Solex 40 PHH carburettors
 * 1964-1965 1800tiSA— 130 PS, 10.5:1 compression, twin Weber DCOE-45 carburettors
 * 1974-1981 E12 518— 66 kW, 8.6:1 compression, Solex 38 PDSI carburettor

1990 cc engines
The M05 version has a displacement of 1990 cc and produces 100 - 120 PS, depending on specification. It has a bore of 89 mm and a stroke of 80 mm.

Applications:
 * 1965-1970 BMW 2000CS— 88 kW, 9.3:1 compression, 2x Solex 40 PHH carburettors
 * 1966-1970 BMW 2000C— 100 PS, 8.5:1 compression, Solex 40 PDSI carburettor
 * 1966-1972 BMW 2000— 100 PS, 8.5:1 compression, Solex 40 PDSI carburettor
 * 1966-1971 BMW 2000ti— 88 kW, 9.3:1 compression, 2x Solex 40 PHH carburettors
 * 1968-1976 BMW 2002— 100 PS, 8.5:1 compression, Solex 40 PDSI carburettor

The M15 version used the Kugelfischer mechanical fuel injection and produced 130 PS. It was also known as the tii engine.

Applications:
 * 1970-1973 2000tii
 * 1972-1974 2002tii
 * 1972-1974 E12 520i

The M17 version produces 115 PS. It has compression ratio of 9.0:1 and uses either a Stromberg 175 CDET or a Solex 4A1 carburettor.

Applications:
 * 1972-1977 E12 520

The M43/1 version has a compression ratio of 8.1:1 and produces 81 kW.

Applications:
 * 1975-1979 E21 320— Solex 32-32 DIDTA carburettor
 * 1975-1979 E21 320i— USA only, Bosch K-Jetronic mechanical fuel injection

The M64 version produces 92 kW. It has a compression ratio of 9.3:1 and uses Bosch K-Jetronic mechanical fuel injection.

Applications:
 * 1975-1978 E21 320i
 * 1975-1979 E12 520i

The M31 version uses a KKK BLD turbocharger operating @ 7psi and produces 125 kW. It has a compression ratio of 6.9:1 and uses Schafer PL 04 mechanical fuel injection.

Applications:
 * 1973-1975 2002 turbo

Related engines

 * The highly successful M12 turbocharged motorsport engine was based on the M10 engine block.


 * The S14 engine used in the E30 M3 was based on the M10 block.