Jalopnik has just named their Engine of the Day as being the legendary M10 engine designed by engineer and race driver Baron Alex von Falkenhausen. The engine was the basis for every New Class model.
In all, over 3.5 million M10/M12 series engines were produced during a 27 years lifespan.
Courtesy of U.S Auto Parts, here is the history behind the M10 engine:
“In the late ’50s, BMW management thought that a 1300 cc engine should be used in the New Class. Considerations of road tax, total weight, and installed engine volume suggested an engine with a modest displacement.
On the other hand, Alex von Falkenhausen felt the new engine should be capable of 2000 cc. He was able to convince the BMW board to accept a 1500 cc engine, and then he designed a 1.5-liter that could be easily expanded to a 2.0-liter.
“I thought we needed to have a good 2-liter“, he said. “So when they agreed to build a 1500, I designed it so it could easily be made an 1800 and then, with a new casting technique, a 2-liter. It was only a year before they wanted a 1600, then in another year an 1800.”"
Some of the popular BMW models powered by this engine or its variations were E21 and E30 3-series cars, and some models from the E12 and E28 5 Series.
Further reading: BMW Engines: From M to N