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 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, but felt that this would be insufficient for the company's future needs. He convinced management that the minimum capacity should be, and offered an engine that could be expanded to a maximum of.

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 and a stroke of, resulting in a displacement of. The peak power rating was.

Naming conventions

The engine was initially known as the "M115". Over the years, variants of the engine were given various codes. In 1975, the engine became known as the "M10", then in 1980 it was given the standardised BMW engine code of M10B18.
The M115 and all related engines have become retroactively known as the "M10" family.

Versions

1499 cc engines

The M115 version has a displacement of and produces. It has a bore of and a stroke of. 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:
The M116 version has a displacement of and produces. It has a bore of and a stroke of. 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—
  • 1966-1975 BMW 1600-2/1602—
  • 1967-1968 BMW 1600 ti—
The M41 version produces, 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, 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 has a displacement of and produces, depending on specification. The bore is and the stroke is.
Applications:
The M118 version has a displacement of and produces, depending on specification. The bore is and the stroke is.
Applications:
  • 1963-1968 1800—, 8.6:1 compression, Solex 36-40 PDSI carburettor
  • 1963-1966 1800ti—, 9.5:1 compression, twin Solex 40 PHH carburettors
  • 1964-1965 1800tiSA—, 10.5:1 compression, twin Weber DCOE-45 carburettors
  • 1974-1981 E12 518—, 8.6:1 compression, Solex 38 PDSI carburettor

    1990 cc engines

The M05 version has a displacement of and produces, depending on specification. It has a bore of and a stroke of.
Applications:
  • 1965-1970 BMW 2000CS—, 9.3:1 compression, 2x Solex 40 PHH carburettors
  • 1966-1970 BMW 2000C—, 8.5:1 compression, Solex 40 PDSI carburettor
  • 1966-1972 BMW 2000—, 8.5:1 compression, Solex 40 PDSI carburettor
  • 1966-1971 BMW 2000ti—, 9.3:1 compression, 2x Solex 40 PHH carburettors
  • 1968-1976 BMW 2002—, 8.5:1 compression, Solex 40 PDSI carburettor
The M15 version used the Kugelfischer mechanical fuel injection and produced. It was also known as the tii engine.
Applications:
The M17 version produces. 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.
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. 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. 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.