Marmon HCM V-12 Prototype

The new car originated as a sketch created by Howard Marmon after meetings with Fred Moscovics, Marmon’s former vice president and general manager who had moved on to Stutz, and chief engineer George Freers. The name HCM, derived from Howard Marmon’s initials, was applied late in the car’s development.

It was to have a tubular backbone and four-wheel independent suspension, using transverse leaf springs front and rear. Two parallel front springs connected to sliding pillars, a concept initiated by Lancia in 1921, which were anchored to outriggers from the narrow center chassis. At the rear, four springs, two forward and two aft, mounted to the differential housing, which formed the center of the chassis. The outer ends of the springs supported the wheel hubs. Drive was by swing axles. The result was very low un-sprung weight, but ride quality suffered, so the front springs were changed to coils mounted on the pillars above the steering knuckle, as in Lancia’s design.

The transmission was a three-speed unit mounted rigidly to the tubular backbone, through which the driveshaft ran. Behind the transmission was an epicyclic overdrive, in turn rigidly bolted to the differential housing. Problems with lubrication and the shift linkage caused this arrangement to be abandoned and replaced by a standard Marmon Sixteen transmission mounted directly behind the engine.

Howard Marmon decided on a V-12 engine, more powerful than an eight but much more economical than his flagship V-16. Engineering was expeditious and based on the V-16, retained the V-16’s bore, stroke, 45-degree cylinder bank angle and wet-liner aluminum construction. It developed 151 bhp at 3,700 rpm, three-quarters of the V-16’s output from an engine three-quarters its size. Initial tests at the Indianapolis Motor Speedway in July of 1932 confirmed acceleration from 10 to 50 mph in a then-remarkable 12.77 seconds, with a 113-mph maximum speed clocked with racing driver Wilbur Shaw at the wheel.

This car was auctioned off by RM Auctions in August of 2011 at the Portola Hotel & Spa and Monterey Conference Center, Monterey, California.

151 bhp, 368 cu. in. OHV aluminum V-12 engine, three-speed manual transmission, sliding-pillar independent coil-spring front suspension, transverse leaf-spring independent rear suspension, and four-wheel mechanical drum brakes. Wheelbase: 134"

Source: RM Auctions
Photo Credit: Copyright

Gallery: Marmon HCM V-12 Prototype