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The M30 engine was BMW's Big Six engine. Although it shared the six-cylinder arrangement of the Baby Six M20 engine, the M30 is actually a development of the four-cylinder M10, with which it shares a number of design features. The M30 is a chain-driven SOHC engine.

Despite its age, the M30 is a powerful engine and has proved to be a very popular engine swap for its excellent torque characteristics.


The M30 started life in the late Sixties, when the power limits of the M10 were realised. By adding two more pistons to the existing design BMW were able to produce their first six-cylinder engine. Crowned the New Six, it became the eponymous powerplant for BMW's Neu Klasse of cars, the E3 and E9. These big motors rolled off the production line in 1968 in 2.5 and 2.8 litre forms, packing a twin-carb setup to get the juices flowing. A 3.0 version followed soon after.

Throughout the Seventies BMW continuously improved the line-up, expanding the capacity range and introducing a new mechanical injection system. They formed the heart of the E12 range and soon found themselves adapted to the biggest range of cars; the 6 series E24 and 7 Series E23. An improved version of the 2.8 litre even smuggled its way into the E28.

But it was the Eighties that really unleashed the potential of the M30. By boring the block out from its original 86mm to 92mm, and extending the stroke from a pathetic 71mm to a mighty 86mm, BMW were able to claim a capacity of 3.4 litres, which they released in two versions. The M30B34 was an asthmatic "economy" version that did its tour of duty in the North American market, whose requirements for a catalytic converter severely sapped the potential of the engine. In contrast, European markets saw the equal-capacity M30B35. Unfettered by pollution concerns, this monster blew out a mighty 218hp and 225 ft/lb of torque, the results of which can be felt all the way through the rev range.

It is the 3.5 litre version that gets used in the M30 engine swap - if it's good enough for Alpina then it's good enough for you.

The M30 even received a turbocharger for the E23. Released in two capacities, the name was changed to M102 for the 3.2 litre, and M106 for the 3.4 litre version.


Engine Displacement Power Torque Redline Bore Stroke Year
M30B25 2.5 L (2478 cc/151 in³)
2.5 L (2494 cc/152 in³)
110 kW (148 hp) @ 5500 rpm 215 N·m (159 ft·lbf) @ 4400 rpm 86mm 71.6mm 1968–1971
M30B28 2.8 L (2769 cc/169 in³)
2.8 L (2986 cc/182 in³)
130 kW (170 hp)
135 kW (181 hp) @ 5800 rpm
251 N·m (185 ft·lbf)
255 N·m (188 ft·lbf) @ 3500 rpm
86mm 80mm
M30B30 3.0 L (2985 cc/182 in³) 135 kW (181 hp) @ 5800 rpm
145 kW (194 hp) @ 5800 rpm
260 N·m (192 ft·lbf) @ 4000 rpm
275 N·m (203 ft·lbf) @ 4000 rpm
89mm 80mm 1976–1985
M30B32 3.2 L (3210 cc/196 in³) 145 kW (194 hp) @ 5500 rpm 285 N·m (210 ft·lbf) @ 4300 rpm 89mm 86mm 1976–1986
M30B34 3.4 L (3430 cc/209 in³) 136 kW (182 hp) @ 5400 rpm 290 N·m (214 ft·lbf) @ 4000 rpm 92mm 86mm 1982–1988
M30B35 3.4 L (3430 cc/209 in³) 163 kW (218 hp) @ 5700 rpm 305 N·m (225 ft·lbf) @ 4000 rpm 92mm 86mm 1988–1993