BMW M10The 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 1400 PS in qualifying trim.
Following the introduction of the BMW M40 engine in 1987, the M10 began to be phased out.
DevelopmentBaron 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 1.3 L, however he felt that this would be insufficient for the company's future needs. Therefore, he convinced BMW that the capacity should be 1.5 L instead and he designed a block that could be expanded to 2.0 L in the future.
DesignThe 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 82 mm and a stroke of 71 mm, resulting in a displacement of 1499 cc. It had hemispherical combustion chambers, an aluminum alloy head and two valves per cylinder. The peak power rating was 80 PS.
Naming conventionsThe 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" represents the 1.8–litre capacity).
The M115 and all related engines have become retroactively known as the "M10" family.
1499 cc enginesThe 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.
1573 cc enginesThe 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.
The M41 version produces 66 kW, has an 8.3:1 compression ratio and fuel is supplied by a Solex 32 DIDTA carburettor.
The M98 version produces 55 kW, has a compression ratio of 9.5:1 and uses a Pierburg 1B2 carburettor.
1766 cc engines
The M10B18 version produces 66 -, depending on specification. The bore is 89 mm and the stroke is 71 mm.
1773 cc enginesThe M118 version has a displacement of 1766 cc and produces 66 -, depending on specification. The bore is 84 mm and the stroke is 80 mm.
1990 cc enginesThe M05 version has a displacement of 1990 cc and produces 75 -, depending on specification. It has a bore of 89 mm and a stroke of 80 mm.
The M15 version used the Kugelfischer mechanical fuel injection and produced 96 kW. It was also known as the tii engine.
The M17 version produces 85 kW. It has compression ratio of 9.0:1 and uses either a Stromberg 175 CDET or a Solex 4A1 carburettor.
The M43/1 version has a compression ratio of 8.1:1 and produces 81 kW.
The M64 version produces 92 kW. It has a compression ratio of 9.3:1 and uses Bosch K-Jetronic mechanical fuel injection.
The M31 version uses a KKK turbocharger and produces 125 kW. It has a compression ratio of 6.9:1 and uses Kugelfischer P04 mechanical fuel injection with a sliding throttle plate.
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.