BMW M30


The BMW M30 is a SOHC straight-six petrol engine which was produced from 1968 to 1995. With a production run of 27 years, it is BMW's 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, with later versions having displacements of up to. 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 M20's production, and prior to the introduction of the BMW M70 V12 engine in 1987, the M30 was BMW's most powerful and largest regular production engine.
Following the introduction of the BMW M50 engine in 1990, the M30 began to be phased out.
Ward's have rated the M30 as one of the "Top Engines of the 20th Century".

Design

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 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 and the versions, which both used an bore.

M90 engine

The M90 engine, used in several models from 1979-1982, combines the block from the motorsports BMW M88 DOHC engine with the M30's SOHC cylinder head.

Versions

M30B25V

The first 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 in most applications. It has a bore of and a stroke of.
The M30B25 has previously been called the M06 and M68, prior to BMW retroactively renaming it the M30B25V.
Applications:
In 1981, Bosch L-Jetronic electronic fuel injection was added to the version. Peak power remained unchanged at, however torque increased slightly to.
Applications:
The M30B28V version produces up to and, 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 and the stroke is.
This version has also been known as the M06 and M68, prior to BMW renaming it the M30B28V.
Applications:
In 1977, Bosch L-Jetronic electronic fuel injection was added to the version. Power increased to and torque increased to.
Based on the M30B28V version with a larger bore, the M30B30V produces and, uses dual Zenith 35/40 INAT carburettors and has a compression ratio of 9.0:1.
Applications:
The fuel injected version of the 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 and, depending on the model year and whether a catalytic converter is fitted. The compression ratio is 9.5:1.
Applications:
Despite having a capacity of, this engine appeared in many cars badged so as to suggest 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 BMW's first use of Bosch's Motronic fuel injection. The bore is and the stroke is.
Applications:
The carburetted M30B33 produces and. It has a bore of and a stroke of.
Applications:
The M30B34 engines sold in Europe and most other markets used a 10.0:1 compression ratio and produced. In North America and Japan, the M30B34 used an 8.0:1 compression ratio and produced. In all markets, the Bosch Motronic digital fuel injection system was used. The bore is and the stroke is.
Applications:
This engine has a capacity of, despite the "B35" model code. It produces and, has a compression ratio of 9.0:1 and uses Bosch Motronic 1.3 digital fuel injection.
Applications:
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 at 6000 rpm and 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.

M102

The M102 was produced from 1980 to 1982. It was BMW's first turbocharged six-cylinder engine.
The M102 has a displacement of. The KKK K27 turbocharger produces of boost and an air-to-air intercooler is used. The compression ratio is 7.0:1.
The M102 produces 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.
Applications:
The M106 replaced the M102 and was produced from 1982 to 1986.
Some of the M106's 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. The compression ratio was increased from 7.0:1 to 8.0:1.
Peak power output is the same as the M102, however it occurs at lower RPM and peak boost is reduced from.
There was no direct successor to the M106, however BMW's next turbocharged petrol engine was the BMW N54, introduced in 2006.
Applications:
The M30 powered a series of E9 CSL and E24 6 Series coupes to European Touring Car Championship 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.