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Vintage Video Double Feature: Chevrolet Learns You Some Stuff

Chev-splaining differentials, torque converters, and diesel fuel injectors

Aaron GoldWriterGetty ImagesPhotographer

It's really a shame that YouTube didn't exist 85 years ago, because back then, Chevrolet was all about explaining stuff. It made a decidedly non-metric ton of films with the Jam Handy organization (oh, do we love that name) covering everything from dealer sales training to straight-up promotion of new Chevrolet models. Among our favorites are the films where they explained how stuff worked, for which they built some rather nifty demonstration models. Some of the technologies explained are, obviously, outdated; I think we can all live our lives without an intimate familiarity with the knee-action independent front suspension. But a lot of the seemingly simplest bits of our cars are the most difficult to figure out, and Chevy had some great explanations, with great visual demonstrations, too.

Around the Corner (1937)

I think we all know what a differential looks like, but actually figuring out what all those little gears do can be a little tricky. We all know they turn at different speeds—but why? And when? And how? Around The Corner tackles this in a most innovative way: Tinkertoys! (Or at least something that looks a lot like Tinkertoys.) Chevy explains the differential with a nifty little model that starts off as a basic rear axle and adds the parts needed to allow the wheels to spin at different speeds. Piece by piece, the video works its way up to the differential we know and love.

Those familiar with Chevy's industrial films know it wouldn't be a Jam Handy jam without a little entertainment, so this film starts off with a little motorcycle stunt riding—which, believe it or not, makes a perfect segue into the science.

The Velvet Glove (1951)

Ah, the automatic transmission torque converter—all but universal today (sadly) and almost universally misunderstood. The problem with explaining a torque converter is that it's difficult to build an operational model that shows off its functions, even with computer modeling. I have heard that General Motors once built a working see-through torque converter, and it cost as much to make as a couple of their cars. This film, while perhaps not quite as good in its explanation as Around the Corner, does a rather decent job explaining the basics of the Powerglide transmission's torque converter, using what looks for all the world like a modified shower head.

What makes this film rather interesting, to me at least, is the other stuff it explains. Chevy had only offered automatic transmissions in its cars for two years in 1951, so the film not only shows how Powerglide works, but how one drives it, and what problems it solves when compared to a manual transmission. It's good, car-geeky stuff. You'll note, by the way, that the film is mostly silent on the planetary gear set and its shifting mechanism. That's because the early Powerglides didn't shift. Selecting Drive locked them into high gear, with the torque converter providing variable drive speeds and torque multiplication. If you needed a lower gear, you manually shifted into Low. Ah, how far we've come.

BONUS TRACK: Diesel—The Modern Power (1938)

This film, made for Electro-Motive, GM's rail subsidiary, is a great explainer of the diesel engine. You probably know the basics of a four-stroke diesel (though I had no idea about the "fire syringe"!), but the explanation of the switch to the two-stroke cycle and details on how unit injectors and superchargers work are pretty cool, as is the breathless newsreel-like coverage of the early streamlined diesel trains these engines powered.

Incidentally, the Winton 201A engine featured in the film turned out to be a lemon. GM's Electro-Motive Division incorporated the lessons learned into the 567, the engine that almost singlehandedly killed the steam locomotive.

Just when you think the film can't get any more interesting, there's an appearance by Charles Kettering, inventor of the self-starter and the coil-distributor ignition (and one of my heroes). He answers the question, "When will I get a diesel in my car?" Funnily enough, his answer was not "1978 and it's going to suck."