Mazda Cosmo Sport: The Space-Age Coupe That Tamed the 'Devil's Claw Marks'

The rotary engine is the most gloriously stubborn idea in the car world. There are no pistons going up and down. Instead, a triangular rotor spins inside an oval-ish housing, and its three tips sweep out the intake, compression, combustion and exhaust phases as it goes round. It's smooth, compact and powerful for its size. In the early 1960s, nobody could make one last.

The deal with NSU

Felix Wankel's design was developed with Germany's NSU, and when NSU announced it, carmakers around the world queued up for licences. Mazda (then Toyo Kogyo) signed in July 1961. Then the problems started.

The worst one: chatter marks. The seals on the rotor's three tips juddered against the housing wall and gouged wavy scars into it, ruining the engine. Mazda's engineers called them "the nail marks of the Devil." After years of trial and error, they cured it with new apex seals made of high-strength carbon infused with aluminium. Plenty of other licensees eventually gave up on the rotary. Mazda didn't.

The car

The result went on sale in May 1967: the Cosmo Sport, sold for export as the 110S. It was one of the first production cars with a twin-rotor Wankel, a 982cc 10A unit making 110 PS. Each rotor had two spark plugs, fed by twin distributors, to keep combustion stable whether you were stuck in traffic or flat out on the expressway.

The body looked as if it had been beamed in from orbit: low, long and slim, with a cockpit set far back. Mazda claimed a top speed of 185 km/h. The cars were essentially hand-built, at about one a day, and only 1,176 were made over two series before production ended in 1972.

84 hours of proof

To prove the rotary wasn't fragile, Mazda chose one of the most brutal races in the world: the 84-hour Marathon de la Route at the Nürburgring in 1968. It entered two near-standard Cosmos. One slid off with a tyre problem after 82 hours. The other finished fourth overall, behind Porsche and Lancia.

Why we love it

The Cosmo Sport is the start of one of the car world's great love affairs. Mazda would go on to build rotary RX-7s and RX-8s and even win Le Mans with one, in 1991. But it all started here, with a tiny company refusing to accept that the Devil's claw marks couldn't be beaten.

Want to know what one actually costs? The Mazda Cosmo Sport Quirk Database entry logs real auction sold prices, each linked to its result.