1923 Chevrolet Series M Copper-Cooled

The 1923 Chevrolet Series M Copper-Cooled model served as definitive proof that nobody is right every time. Engineering genius Charles Kettering, who'd devised the electric self-starter years earlier, got another bright idea in the early 1920s: an air-cooled engine.

1923 Chevrolet Series M Copper-Cooled
The air-cooled 1923 Chevrolet Series M was beset by overheating problems. See more pictures of Chevrolet Series cars.

Air cooling wasn't new, as verified by the success of the Franklin. But Kettering's concept, promising on paper, proved to be a disaster.

GM wanted an engine that was high in performance, light in weight, low in cost, and easy to maintain; a tall order, but not impossible.

Kettering exhibited the Copper-Cooled engine in January at the New York Auto Show, vowing that it would eventually replace water-cooling. Smaller than usual, it displaced only 135 cubic inches and yielded 22 horsepower (at 1,750 rpm). Cooling was accomplished using U-shaped copper fins bonded to separately cast cylinders.

Priced about $200 higher than the water-cooled Superior B series, which was essentially an upgraded 490, the Copper-Cooled Chevrolet wore the same body as the Superior B, but weighed some 215 pounds less.

Because of uneven air distribution, production engines began to overheat badly, causing severe detonation. Breathing poorly when hot, power also fell sharply.

Production stopped after 500 cars, and nearly all were recalled. By 1923, Chevrolet was the chief GM rival to Ford, but this fiasco didn't help Chevy's image.

1923 Chevrolet Series M Copper-Cooled
The Series M was Chevy's last attempt at
an air-cooled engine for nearly 40 years.

1923 Chevrolet Series M Copper-Cooled Facts
Weight (lbs.)
Price range (new)
Number built
Series M
1,700 (approx.)

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