Топ-100
  • BMW M57 BMW M57

    The M57 is a water-cooled and turbocharged inline six cylinder diesel engine with common-rail-injection. It was revised twice during its production time. It ...

  • BMW M70 BMW M70

    The BMW M70 is a SOHC V12 petrol engine, which was BMWs first production V12 and was produced from 1987 to 1996. The BMW S70/2 engine, largely unrelated to t...

  • BMW M47 BMW M47

    The BMW M47 and Rover Group M47R are straight-4 Diesel engines. Variants were manufactured by BMW from 1998 to 2007. BMW gradually adopted high-pressure comm...

  • BMW M62 BMW M62

    The BMW M62 is a naturally aspirated V8 petrol engine which was produced from 1995 to 2005. A successor to the BMW M60, the M62 features an aluminium engine ...

  • BMW M43 BMW M43

    The BMW M43 is an SOHC four-cylinder petrol engine which was produced from 1991-2002. The M43 powered base-model cars, while higher performance models at the...

  • BMW M40 BMW M40

    The BMW M40 is an SOHC four-cylinder petrol engine which was produced from 1987–1994. It served as BMWs base model four-cylinder engine and was produced alon...

  • BMW M30 BMW M30

    The BMW M30 is a SOHC straight-six petrol engine which was produced from 1968 to 1994. With a production run of 22 years, it is BMWs longest produced engine ...

  • BMW M4 BMW M4

    The BMW M4 is a high-performance version of the BMW 4 Series automobile developed by BMWs motorsport division, BMW M GmbH. Part of the renumbering that split...

  • BMW M88 BMW M88

    The BMW M88 is a straight-6 DOHC petrol engine which was produced from 1978-1989. It is based on the DOHC version of the BMW M49 engine, which was used in th...

  • BMW M50 BMW M50

    The BMW M50 is a straight-6 DOHC petrol engine which was produced from 1990 to 1996. It was released in the E34 520i and 525i, to replace the M20 engine. In ...

  • BMW M5 BMW M5

    The BMW M5 is a high performance variant of the BMW 5 Series marketed under the BMW M sub-brand. It is considered an iconic vehicle in the sports sedan categ...

  • BMW M1 BMW M1

    The BMW M1 is a mid-engined sports car produced by German automotive manufacturer BMW from 1978 to 1981. In the late 1970s, Italian automobile manufacturer L...

  • BMW M60 BMW M60

    The BMW M60 is a naturally aspirated V8 petrol engine which was produced from 1992 to 1996. It was BMWs first V8 engine in over 25 years. The M60 was replace...

  • BMW M6 BMW M6

    The BMW M6 is a high-performance version of the 6 Series marketed under the BMW M sub-brand from 1983–2018. Introduced in the coupe body style, the M6 was al...

  • BMW M3 BMW M3

    The BMW M3 is a high-performance version of the BMW 3 Series, developed by BMWs in-house motorsport division, BMW M GmbH. M3 models have been produced for ev...

BMW M20

The BMW M20 is a SOHC straight-six petrol engine which was produced from 1977 to 1993. It was introduced eight years after the larger BMW M30 straight-six engine, which remained in production alongside the M20.
The first cars to use the M20 were the E12 5 Series and the E21 3 Series. The initial M20 model had a displacement of 2.0 L 122 cu in, with later versions having displacements of up to 2.7 L 165 cu in.
The M20 began to be phased out following the introduction of the M50 engine in 1990. The final M20 engines were fitted to the E30 3 Series wagon estate and convertible model built in April 1993.
The M20 was the basis for the BMW M21 diesel engine. It is also loosely related to the BMW M70 V12 petrol engine.

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1. History
By the 1970s, BMW felt the need for a six-cylinder engine smaller than the BMW M30, to use in the 3 Series and 5 Series. The resulting M20 had a displacement of 2.0 L 122 cu in, BMWs smallest straight-six engine of its day. Later versions had displacements up to 2.7 L 165 cu in and the M20 was used in the E12 5 Series, E21 3 Series, E28 5 Series, E30 3 Series and E34 5 Series.
Early versions of the M20 were sometimes referred to as the "M60", although the BMW M60 code has since been used for a V8 engine produced from 1992-1996.

2. Design
As per the M30, the M20 has an iron block, aluminium head and a SOHC valvetrain with 2 valves per cylinder. The major differences to the M30 are:
Slant angle of 20 degrees, compared with 30 degrees for the M30.
A timing belt rather than a timing chain
Bore spacing of 91 mm 3.6 in, rather than 100 mm 3.9 in

3.1. Models M20B20
The first models to use the M20 were the E12 520/6 and the E21 320/6, which used the 1.991 cc 121 cu in M20B20. This engine uses a bore of 80 mm 3.15 in and a stroke of 66 mm 2.60 in. The M20B20 initially used a Solex 4A1 four-barrel carburetor, had a compression ratio of 9.2:1 and a redline of 6.400 rpm.
The M20B20 first became fuel-injected in 1981, with Bosch K-Jetronic used. The compression ratio was raised to 9.9:1. In September 1982 coinciding with the release of the E30 3 Series, the fuel injection was updated to LE-Jetronic with a redline of 6.200 rpm. Other upgrades included a larger port known as "731" cylinder head, a lighter block and new manifolds. The M60 designation was finally dropped and replaced with M20.
In 1987, the M20B20 was again revised with the addition of Bosch Motronic engine management, a catalytic converter and a compression ratio of 8.8:1.
The M20B20 was not sold in North America.
Applications:
1977–1982 E21 320/6 carburettor
1982–1984 E30 320i L-Jetronic
1987–1992 E30 320i Motronic
1986–1987 E28 520i Motronic
1981–1982 E28 520i K-Jetronic
1976–1981 E12 520/6 carburettor
1984–1987 E28 520i LE-Jetronic
1984–1987 E30 320i LE-Jetronic
1982–1984 E28 520i L-Jetronic
1988–1990 E34 520i Motronic

3.2. Models M20B23
Six months after the M20 was launched with the carburetted M20B20, the larger, fuel-injected M20B23 was introduced for March 1978. The initial version of the M20B23 uses the same head known as "200" and block as the M20B20 but a longer 76.8 mm 3.02 in stroke crank. The bore is 80 mm 3.15 in. Fuel injection was K-Jetronic, the compression ratio is 9.5:1 and the redline is 6.400 rpm.
The 1982 version used LE-Jetronic, the 731 cylinder head, a compression ratio of 9.8:1 and the other upgrades as the per the M20B20; this resulted in a power output of 139 bhp 104 kW.
In 1984, the fuel-injection, exhaust and camshaft were upgraded to LE-Jetronic and power increased to 112 kW 150 bhp with a redline of 6.500 rpm.
The M20B23 was not sold in North America.
Applications:
1977–1982 E21 323i K-Jetronic
1982–1984 E30 323i L-Jetronic
1984–1987 E30 323i LE-Jetronic

3.3. Models M20B25
In 1985, the M20B25 replaced the M20B23. The M20B25 has a capacity of 2.494 cc 152.2 cu in and initially produced 126 kW 171 PS; 169 bhp without a catalytic converter. It has an upgraded cylinder head known as "885", a bore of 84 mm 3.31 in, a stroke of 75 mm 2.95 in, a compression ratio of 9.4:1, a redline of 6.500 rpm and uses Bosch Motronic 1.1 engine management.
In 1987, a catalyzed model with Motronic 1.3 engine management was introduced. The compression ratio was reduced to 8.8:1 but thanks to the more sophisticated electronics power remained nearly as before, at 125 kW 170 PS; 168 bhp. The uncatalyzed engine was kept in production for Southern Europe and other markets where unleaded petrol was not regularly available.
Applications:
1988–1991 Z1
1989–1990 E34 525i
1985–1993 E30 325i

3.4. Models M20B27
The M20B27 was designed for efficiency thus the e for the Greek letter eta in 325e and low-rev torque. This is an unusual design strategy for a BMW straight-six engine, which are usually designed for power at high RPM. Compared with the M20B25, the stroke is increased from 75 to 81 mm 2.95 to 3.19 in, resulting in a capacity of 2.693 cc 164.3 cu in. As per the M20B25, the bore is 84 mm 3.31 in. To reduce friction and improve efficiency, the M20B27 changes include using the 200 version of the head which has smaller ports, a different camshaft, four camshaft journals and softer valve springs. Due to these changes the rev limit on the M20B27 was reduced to 4.800 rpm. A compression ratio of 9.0:1 was used on the US 528e, and 11:1 on Euro 525e and 325e cars - this was reduced to 10.3:1 in 1985. The initial M20B27 engines produces 92 kW 123 bhp and 240 N⋅m 177 lb⋅ft at 3.250 rpm for models without a catalytic converter. Models with a catalytic converter produce 90 kW 121 bhp and 230 N⋅m 170 lb⋅ft.
Since many markets tax cars based on engine displacement, the etas larger displacement meant that it was not suitable for all markets. It was expressly developed with the American market in mind. BMWs corporate average fuel economy was at risk of not meeting requirements by 1984, primarily due to higher sales of their bigger, more expensive cars in the early 1980s. The first car to use the M20B27 was the US market 528e in 1982.
In late 1987, the fuel injection was upgraded to Motronic 1.3 on the US market plastic bumper 325e Super Eta, the cylinder head changed to the "885" version, the compression ratio was reduced to 8.5:1 and the redline increased to 5.200 rpm. Power output increased to 95 kW 127 bhp at 4.800 rpm.
In the early 1990s BMW South Africa used components from the Alpina C3 2.7 to produce an E30 specifically for Stannic Group N production car racing. The first iteration of this engine used in the E30 325iS produced 145 kW 194 bhp and the second revision, often referred to as "Evo2" or on the VIN plate as "HP2" produced 155 kW 208 bhp.
Applications:
1989–1992 E30 325iS only available in South Africa
1982–1988 E28 525e called 528e in North America
1982–1987 E30 325e, 325e

BMW M3

The BMW M3 is a high-performance version of the BMW 3 Series, developed by BMWs in-house motorsport division, BMW M GmbH. M3 models have been produced for ev...

BMW M6

The BMW M6 is a high-performance version of the 6 Series marketed under the BMW M sub-brand from 1983–2018. Introduced in the coupe body style, the M6 was al...

BMW M60

The BMW M60 is a naturally aspirated V8 petrol engine which was produced from 1992 to 1996. It was BMWs first V8 engine in over 25 years. The M60 was replace...

BMW M1

The BMW M1 is a mid-engined sports car produced by German automotive manufacturer BMW from 1978 to 1981. In the late 1970s, Italian automobile manufacturer L...

BMW M5

The BMW M5 is a high performance variant of the BMW 5 Series marketed under the BMW M sub-brand. It is considered an iconic vehicle in the sports sedan categ...

BMW M50

The BMW M50 is a straight-6 DOHC petrol engine which was produced from 1990 to 1996. It was released in the E34 520i and 525i, to replace the M20 engine. In ...

BMW M88

The BMW M88 is a straight-6 DOHC petrol engine which was produced from 1978-1989. It is based on the DOHC version of the BMW M49 engine, which was used in th...

BMW M4

The BMW M4 is a high-performance version of the BMW 4 Series automobile developed by BMWs motorsport division, BMW M GmbH. Part of the renumbering that split...

BMW M30

The BMW M30 is a SOHC straight-six petrol engine which was produced from 1968 to 1994. With a production run of 22 years, it is BMWs longest produced engine ...

BMW M40

The BMW M40 is an SOHC four-cylinder petrol engine which was produced from 1987–1994. It served as BMWs base model four-cylinder engine and was produced alon...

BMW M43

The BMW M43 is an SOHC four-cylinder petrol engine which was produced from 1991-2002. The M43 powered base-model cars, while higher performance models at the...

BMW M62

The BMW M62 is a naturally aspirated V8 petrol engine which was produced from 1995 to 2005. A successor to the BMW M60, the M62 features an aluminium engine ...

BMW M47

The BMW M47 and Rover Group M47R are straight-4 Diesel engines. Variants were manufactured by BMW from 1998 to 2007. BMW gradually adopted high-pressure comm...

BMW M70

The BMW M70 is a SOHC V12 petrol engine, which was BMWs first production V12 and was produced from 1987 to 1996. The BMW S70/2 engine, largely unrelated to t...

BMW M57

The M57 is a water-cooled and turbocharged inline six cylinder diesel engine with common-rail-injection. It was revised twice during its production time. It ...