If one engine is good, two must be better, especially when they break down so often. That was the logic behind the 1907 Carter Two-Engine Car.

In the early development of the automobile, unorthodox ideas were more commonplace. After all, the automobile was an unorthodox idea itself. There was far more room for  experiment back then, as who knew what the next great idea might be. Take for example the 1907 Carter Two-Engine Car, the creation of Howard O. Carter, a native of  Detroit. (He was no apparent relation to Byron Carter of Cartercar, and there are several more stories there.)

According to Scientific American in November 1907, the idea of a dual-engine auto came to Carter when his conventional single-engine vehicle broke down and left him stranded—a common occurance in those days. From that, he reasoned, a car with two complete engines would offer greater reliability. In the event of a mechanical mishap, one could simply start up the second engine and be on one’s way.

This belt-and suspenders approach to automotive engineering immediately reminded us of Henry Ford’s decision that same year to revert his six-cylinder Model K from dual to single ignition. As he saw it, the need for a second complete ignition system was a blatant admission that the first one must not be any good.

In the Scientific American report, there were multiple versions of the Carter Two-Engine proposed, equipped with four or six-cylinder engine pairs. Hwoever, all used the same basic drivetrain layout as covered by Carter’s patent, U.S. no. 845850. The engines were mounted side-by-side, linked to a midship-mounted transmission with a pair of silent Morse chains and cone clutches. Thus the driver could select either engine, depending which one was functioning  at the time, we suppose, or engage both when total power was called for.

Trade journal stories of the period typically showed a pair of air-cooled inline fours of 20 hp each, but in 1908 Motor described a water-cooled version with two inline fours of 284 cubic inches each and a combined 70 hp. Considerably larger than the standard Carter, it boasted a 132-inch wheelbase and a price of $5,000.

There’s a period postcard that shows a Carter Two-Engine Car in use by the Washington DC Fire Department. (Image courtesy David Greenlees of The Old Motor.) We can imagine the appeal of the Carter for fire personnel: the promise of total reliability, a quality that many automobiles of the time did not possess.

Indeed. Carter’s advertising declared, “The car with the right principle is reliable under all conditions.” Another slogan was “two hearts beating as one.” However, the purported reliability came at considerable weight, complexity, and not to mention, cost: $2,250 for the standard air-cooled Model A and $5,000 for the deluxe 70 hp version.

Carter first announced that the cars would be produced in Detroit, then made plans to construct a plant in Maryland, predicting that production would soon reach 20,000 cars per year. However, it is unknown how many were eventually built; we’re guessing probably no more than a handful. We’ve never heard of any examples still in existence, but if there’s one around we’d be thrilled to learn about it.