Porsche flat-twelve engine

Overview

The Type 912 engine was Porsche’s first twelve-cylinder unit, created by chief engineer Hans Mezger under Ferdinand Piëch and Helmuth Bott. It was an air-cooled 4.5-liter design that essentially bolted together two of Porsche’s existing 2.25-liter flat-six racing engines. The layout was a 180-degree flat-twelve, with twin overhead camshafts driven by centrally mounted gears, twin spark plugs fed from two distributors, and a large horizontal cooling fan also driven from those central gears. To save weight, the engine used titanium, magnesium, and other exotic alloys originally developed for the lightweight Bergspider hill climb cars.

Some weight-saving tricks were simple—like a birch wood gear shift knob—while others were extreme, such as using the car’s tubular frame itself as oil piping to route oil to the front cooler. At Le Mans, the heavily favored Gulf-backed John Wyer Automotive team entered three 917Ks: two with the 4.9-liter engine and one with the 4.5-liter. Two 917 LH cars also competed, one in white and red trim from Porsche Salzburg.

Those drivers were also listed on the team’s other car—a red and white 917K with the 4.5-liter engine, qualified 15th by Hans Herrmann and Richard Attwood—but they did not drive it after their own car failed. That 4.5-liter car picked up the nicknames Hippie Car and Psychedelic Porsche from the team and media. In the end, it was the red and white #23 917K from Porsche Salzburg, with the standard 4.5-liter engine, that won overall at Le Mans. Driven carefully through heavy rain by Stuttgart’s Hans Herrmann and Englishman Richard Attwood, the car secured Porsche’s first overall victory at the race, which saw only seven ranked finishers.