BMW M30

Infobox Automobile
name=BMW M30 engine


manufacturer=BMW
production=1968–1994
predecessor=
successor=BMW M60 V8
class=Straight-6
engine=2.5 L (2494 cc/152 in³)
2.8 L (2788 cc/170 in³)
3.0 L (2986 cc/182 in³)
3.2 L (3210 cc/195 in³)
3.4 L (3430 cc/209 in³)The BMW M30 is an inline-6 cylinder engine built by BMW and was used in many different models since 1968. It was originally developed in the late 1960s as an extended 2.5 liter version of the robust inline four cylinder BMW M10 first used in the 'Neue Klasse' BMW 1500, with which it shares a number of design features, including a 30-degree cant to the right for a lower profile, a crossflow head design, and a chain-driven single overhead cam with rocker arm valve actuation. The 'Big Six,' also known as the 'Senior Six,' got its informal names after the introduction of a smaller BMW M20 belt-driven SOHC six cylinder in the late '70s.

The M30 powered a series of BMW 6-cylinder E9 and BMW E24 coupes to European Touring Car Championship (ETCC) throughout the '70s and into the middle 1980s, even though a more powerful DOHC 24-valve head had been developed for high performance motorsports and street use.

A production turbo variant of the M30 designated the M102B32 or M102B35 (depending on 3.2 or 3.4 liter displacement) was used in the BMW E23 Seven Series where it was designated "745i", based on a then-current projection that the horsepower produced was roughly equal to that of a 4.5 liter normally-aspirated engine. The 3.5 DOHC M5 and M6 engine was used in the South African 745i from 1984-1986.

The M30 engines all feature Bosch L-Jetronic multipoint fuel injection.

BMW's M30 straight six cylinder engines had the longest production run of any BMW engine, dating back to the 1968 E3 sedans and E9 coupes. The last use of the block was the 1994 E32 730i. Displacement ranged from 2.5 to 3.4 liters with a 100 mm bore spacing.

The M30 engine's bottom end is virtually 'bulletproof' and a true workhorse. The M30's timing chain is designed to last the life of the engine and it will, if the timing chain tensioner is maintained. Unfortunately, over time and use, the plastic parts in it can fail but they are easily replaced. The alloy head is prone to warping if the engine is overheated (especially around the somewhat restricted cooling system passages near the middle), but with regular cooling system maintenance, oil changes, and other routine maintenance, the M30 can routinely run well past 250,000 miles.

= Known Problems [http://www.bmwe34.net/Wiki/tiki-index.php?page=What+will+break] =

"These problems may not necessarily apply to all versions of the M30 engine."

* An "oil spray bar" is mounted above the camshaft. This hollow metal tube sprays oil over the camshaft and rocker arms, but with time the two banjo bolts that hold the bar in place may loosen themselves. As a result, oil passage through the spray bar will get restricted, and the camshaft and rocker arms will not get cooled and lubricated properly, possibly leading to fatal wear.

* On some models, the return valve in the oil filter housing fails with time, thus making oil run out after stopping the engine, instead of keeping it in the housing. While not a critical problem, it results in the engine needing up to five seconds to build up proper oil pressure upon engine start. BMW replaced the oil filter housing with a more durable valve around 1991.

* While not a problem by design, the spacing between the valve rocker arms and the valves must be adjusted approximately every 30,000 km (20,000 miles). Failure to adjust might lead to poor running, increased fuel consumption, and engine wear.

* The engine fan is mounted with a viscous coupling that expands when heated. As the engine becomes warm, the coupling gets a better grip on the fan, thus leading to increased rotation of the fan, and more airflow. If this viscous coupling fails, the fan will only rotate relatively slowly (as driven by the engine by a V-belt), and will not provide sufficient cooling, leading to overheating. Overheating can extremely quickly lead to engine failure, such as a destroyed headgasket or a warped or partly melted cylinder head.

__NOTOC__

M30B25V

Applications:
* 1973-1976 E12 525
* 1976-1981 E12 525

M30B25

Applications:
* 1981-1987 E28 525i

M30B28

2.8 L (2788 cc) Applications:
* 1979-1987 E24 628CSi
* 04/1981-12/1987 E28 528i

M30B30

Introduced in 1986 with the E32, the 3.0 L (2986 cc) M30B30 produced 185 hp. The engine continued in production until 1994.

Applications:
* 1986-1994 E32 7-Series
* 1988-1993 E34 5-Series

3.0 L (2986 cc) Applications:
* 1976-1979 E24 630CS

M30B32

3.2 L (3210 cc) Applications:
* 1976-1984 E24 633CSi

M30B34

3.4 L
* 8.5:1 compression ratio

Applications:
* 1985-1988 E28 5-Series
* 1985-1987 E24 6-Series
* 1985-1987 E23 7-Series

3.4 L (3430 cc)Applications:
* 1983-1993 Europe
* 1985-1993 US

M30B35

* 3.4 liter (3430 cc) SOHC inline-6 cylinder
* 9.0:1 compression ratio
* 208 hp @ 5700 rpm
* 225 ft·lbf torque @ 4000 rpm
* 87 AKI / 91 RON octane fuel or better recommended

Applications:
* 1988-1989 E24 635CSi
* 1988-1993 E34 535i
* 1988-1992 E32 735i

3.5 L (3453 cc) Applications:
* 1978-1983 E24 635CSi

3.5 L (3453 cc) DOHC Applications:
* 1987-1989 E24 M6
* 1984-1988 M635csi/M6
* 1984-1986 745i - South Africa

ee also

*BMW M10 - 4-cylinder engine M30 was based on.
*BMW M20 - 6-cylinder "little six" engine.

References

External links

* [http://www.bmwinformation.com/engines/straight6_m.html BMW Engines - Straight6_m]
* [http://www.vrchlabi.cz/e30/ruzne/enginenumber/ BMW Engine Numbers]
* [http://www.unixnerd.demon.co.uk/enumber.html BMW E Numbers List]