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 and was used in many car models.
The first models to use the M30 engine were the BMW 2500 and 2800 sedans. The initial M30 models were produced in displacements of 2.494–2.986 cc 152.2–182.2 cu in, with later versions having displacements of up to 3.430 cc 209.3 cu in. As per the BMW M10 four-cylinder engine from which the M30 was developed, the M30 has an iron block, an aluminium head and an overhead camshaft with two valves per cylinder.
The engine was given the nicknames of Big Six and Senior Six, following the introduction of the smaller BMW M20 straight-six engine in the late 1970s. The M30 was produced alongside the M20 throughout the M20s production, and prior to the introduction of the BMW M70 V12 engine in 1987, the M30 was BMWs most powerful and largest regular production engine.
Following the introduction of the BMW M50 engine in 1990, the M30 began to be phased out.
Wards have rated the M30 as one of the "Top Engines of the 20th Century".
The M30 was originally developed in the late 1960s, loosely based on the BMW M10 four-cylinder engine first used in the BMW New Class sedans and coupes. Initially, the engine code was "M06", until it was later renamed the M30.
Common features between the M10 and M30 include a profile lowering 30-degree slant to the right, a crossflow cylinder head a gas flow head in later designs and chain-driven camshaft with rocker arm valve actuation. Further similarities include a cast-iron block with an aluminium head and a forged crankshaft. The first two M30 engines introduced were the 2.788 cc 170.1 cu in and the 2.494 cc 152.2 cu in versions, which both used an 86 mm 3.39 in bore.
2.1. Versions M30B25V
The first 2.494 cc 152.2 cu in version of the M30 was introduced in the 1968 E3 2500. This version uses dual Solex Zenith 35/40 INAT carburettors, has a compression ratio of 9.0:1 and produces 110 kW 148 bhp in most applications. It has a bore of 86 mm 3.39 in and a stroke of 86 mm × 71.6 mm 3.39 in × 2.82 in.
The M30B25 has previously been called the M06 and M68, prior to BMW retroactively renaming it the M30B25V V for Vergaser - carburettor in German.
- 1973–1976 E12 525 - 107 kW 143 bhp, Solex 4A1 carburettor
- 1968–1977 E3 2500
- 1976–1981 E12 525
- 1977–1979 E23 725
- 1974–1975 E9 2.5 CS
2.2. Versions M30B28V
The M30B28V version produces up to 125 kW 168 bhp and 235 N⋅m 173 lb⋅ft, depending on the model year, carburettor and country. It has a compression ratio of 9.0:1 and initially used dual Zenith 35/40 INAT carburettors. The bore is 86 mm 3.39 in and the stroke is 86 mm × 80 mm 3.39 in × 3.15 in.
This version has also been known as the M06 and M68, prior to BMW renaming it the M30B28V.
- 1977-1979 E23 728 - 125 kW 168 bhp, Solex 4A1 carburettor
- 1971-1971 E3 Bavaria - United States only
- 1974-1976 E12 528 - 121 kW 162 bhp, dual Zenith INAT carburettors
- 1968-1971 E9 2800 CS
- 1968-1977 E3 2800 / 2.8L - 125 kW 168 bhp
- 1976-1978 E12 528 - 125 kW 168 bhp, Solex 4A1 carburettor
2.3. Versions M30B28
In 1977, Bosch L-Jetronic electronic fuel injection was added to the 2.788 cc 170.1 cu in version. Power increased to 135 kW 181 bhp and torque increased to 240 N⋅m 177 lb⋅ft.
- 1977-1978 E12 528i - North America only, 129 kW 173 bhp, 9.0:1 compression ratio
- 1979-1987 E24 628CSi
- 1978-1981 E12 528i
- 1981-1987 E28 528i
- 1979-1986 E23 728i
2.4. Versions M30B30V
Based on the M30B28V version with a 3 mm 0.12 in larger bore, the M30B30V produces 132 kW 177 bhp and 255 N⋅m 188 lb⋅ft, uses dual Zenith 35/40 INAT carburettors and has a compression ratio of 9.0:1.
- 1971-1974 E3 3.0 S / 3.0 L / Bavaria
- 1971-1975 E9 3.0 CS
- 1971-1972 E9 3.0 CSL
- 1976-1979 E24 630 CS - 136 kW 182 bhp, Pierburg 4A1 carburetor
- 1977-1979 E23 730 - 135 kW 181 bhp, Solex 4 A 1 carburettor
2.5. Versions M30B30
The fuel injected version of the 2.986 cc 182.2 cu in M30 debuted in 1971 in the E9 3.0 CSi and initially used the Bosch D-Jetronic mechanical fuel injection system. In 1976, the fuel injection system was upgraded to Bosch L-Jetronic electronic fuel injection. The M30B30 produces up to 149 kW 200 bhp and 272 N⋅m 201 lb⋅ft, depending on the model year and whether a catalytic converter is fitted. The compression ratio is 9.5:1.
- 1972-1973 E9 3.0 CSL - 149 kW 200 bhp
- 1976-1976 E12 530 MLE - South Africa only, 147 kW 197 bhp
- 1972-1975 E3 3.0 Si - 147 kW 197 bhp
- 1977-1978 E24 630CSi - North America only, 129 kW 173 bhp
- 1988-1990 E34 530i - 138 kW 185 bhp
- 1971-1975 E9 3.0 CSi - 149 kW 200 bhp
- 1986-1994 E32 730i - 138 kW 185 bhp
- 1975-1978 E12 530i - North America only, 131 kW 176 bhp
2.6. Versions M30B32
Despite having a capacity of 3.210 cc 195.9 cu in, this engine appeared in many cars badged so as to suggest 3.3 L 201 cu in of displacement- such as the 633i, 3.3 Li, and 733i. The compression ratio is 8.8:1. In the E24 633CSi coupe, the M30B32 uses Bosch L-Jetronic electronic fuel injection. The US version used L-Jetronic from 1978 until mid-1981, changing over to Motronic digital fuel injection in June of that year. The 1979 732i is BMWs first use of Boschs Motronic fuel injection. The bore is 89 mm 3.50 in and the stroke is 86 mm 3.39 in.
- 1984-1986 E30 333i - South Africa only, 145 kW 194 bhp
- 1982-1984 E28 533i - North America only, 135 kW 181 bhp
- 1976-1979 E3 3.3 Li - 147 kW 197 bhp
- 1979-1981 E12 533i - North America only, 135 kW 181 bhp
- 1977-1984 E23 733i - 147 kW 197 bhp in Euro spec, 130–145 kW 174–194 bhp in USA spec
- 1973-1975 E9 3.0 CSL - 152 kW 204 bhp, 3.153 cc 192.4 cu in
- 1976-1984 E24 633CSi - 145–147 kW 194–197 bhp in Euro spec, 128–130 kW 172–174 bhp in USA spec
- 1979-1986 E23 732i - 144 kW 193 bhp
2.7. Versions M30B33V
The carburetted M30B33 produces 139 kW 186 bhp and 289 N⋅m 213 lb⋅ft. It has a bore of 89 mm 3.50 in and a stroke of 88 mm 3.46 in.
- 1973-1975 E3 3.3 L
2.8. Versions M30B34
The M30B34 engines sold in Europe and most other markets used a 10.0:1 compression ratio and produced 160 kW 215 bhp. In North America and Japan, the M30B34 used an 8.0:1 compression ratio and produced 136 kW 182 bhp. In all markets, the Bosch Motronic digital fuel injection system was used. The bore is 92 mm 3.62 in and the stroke is 86 mm 3.39 in.
- 1985-1988 E28 535i / 535is / M535i
- 1982-1987 E23 735i / L7
- 1982-1987 E24 635CSi / L6 - 163 kW 219 bhp in Euro spec
2.9. Versions M30B35
This engine has a capacity of 3.430 cc 209.3 cu in, despite the "B35" model code. It produces 155 kW 208 bhp and 305 N⋅m 225 lb⋅ft, has a compression ratio of 9.0:1 and uses Bosch Motronic 1.3 digital fuel injection.
- 1986-1992 E32 735i
- 1988-1989 Rayton Fissore Magnum 3.5
- 1988-1989 E24 635CSi
- 1987-1992 E34 535i
The M30 was the basis for the turbocharged M102 and M106 engines.
The Alpina B10 Biturbo used a modified version of the M30, with two turbochargers and forged pistons. Producing 265 kW 355 bhp at 6000 rpm and 520 N⋅m 384 lb⋅ft at 4000 rpm, the engine made this car the fastest sedan in the world. The final 50 M30 blocks were shipped to Alpina for use in the final 50 B10 Biturbos.
3.1. Turbocharging M102
The M102 was produced from 1980 to 1982. It was BMWs first turbocharged six-cylinder engine.
The M102 also known as M30B32LAE has a displacement of 3.210 cc 195.9 cu in. The KKK K27 turbocharger produces 9 psi 0.62 bar of boost and an air-to-air intercooler is used. The compression ratio is 7.0:1.
The M102 produces 188 kW 252 bhp and was used in the E23 7 Series, in the model was designated "745i". The M102 was not available in right-hand drive cars, leading to the South African 745i using the BMW M88 naturally aspirated DOHC straight-six engine instead.
- 1980–1982 E23 745i
3.2. Turbocharging M106
The M106 also called M30B34MAE replaced the M102 and was produced from 1982 to 1986.
Some of the M106s upgrades over its predecessor are a result of the M30B34 version of the M30, which was also released in 1982. These upgrades include Bosch Motronic engine management and an increased displacement to 3.430 cc 209.3 cu in. The compression ratio was increased from 7.0:1 to 8.0:1.
Peak power output is the same 185 kW 248 bhp as the M102, however it occurs at lower RPM and peak boost is reduced from 9 to 6 psi 0.62 to 0.41 bar.
There was no direct successor to the M106, however BMWs next turbocharged engine was the BMW N54, introduced in 2006.
- 1982-1986 E23 745i
The M30 powered a series of E9 CSL and E24 6 Series coupes to European Touring Car Championship ETCC throughout the 1970s and into the middle 1980s, even though a more powerful DOHC 24-valve head had been developed for high-performance motorsports and street use.
The BMW M88 high-performance engine is based on the M30 block.