BMW M10


The BMW M10 is an SOHC four-cylinder petrol engine which was produced from 1962-1988. It was BMW's first four-cylinder engine since the BMW 309 ended production in 1936 and was introduced in the New Class sedans.
Over 3.5 million M10 engines were produced during the M10's 26 year production run, and it was used in many BMW models.
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 to design an engine with a displacement of, however he felt that this would be insufficient for the company's future needs. Therefore, he convinced BMW that the capacity should be instead and he designed a block that could be expanded to in the future.

Design

The M10 has a forged crankshaft, counterbalance weights, five main bearings and a chain-driven camshaft. The block is made from cast iron and the head is made from aluminium. The initial version of the M10 had a bore of and a stroke of, resulting in a displacement of. It had hemispherical combustion chambers, an aluminum alloy head and two valves per cylinder. 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 then "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.
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The M41 version produces, has an 8.3:1 compression ratio and fuel is supplied by a Solex 32 DIDTA carburettor.
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The M98 version produces, has a compression ratio of 9.5:1 and uses a Pierburg 1B2 carburettor.
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The M10B18 version produces, depending on specification. The bore is and the stroke is.
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The M118 version has a displacement of and produces, depending on specification. The bore is and the stroke is.
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The M05 version has a displacement of and produces, depending on specification. It has a bore of and a stroke of.
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The M15 version used the Kugelfischer mechanical fuel injection and produced. It was also known as the tii engine.
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The M17 version produces. It has compression ratio of 9.0:1 and uses either a Stromberg 175 CDET or a Solex 4A1 carburettor.
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The M43/1 version has a compression ratio of 8.1:1 and produces.
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The M64 version produces. It has a compression ratio of 9.3:1 and uses Bosch K-Jetronic mechanical fuel injection.
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The M31 version uses a KKK turbocharger and produces. It has a compression ratio of 6.9:1 and uses Kugelfischer P04 mechanical fuel injection with a sliding throttle plate.
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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.