CC Video: Detroit Diesel 1-71 and 12V-71 – The Smallest “Screaming Jimmy” and The Biggest

Since we’re on a bit of a diesel-fueled jag here, how about we take a listen (and look, although that’s secondary) to the two extreme ends of the 71 family. As you probably know, all of them have 71 cubic inches per cylinder, and they were made in 1, 2, 3, 4, 6, V6, V8, and V12 formats. There was also a V16, but it’s really mostly two V8s joined together.

The 1-71 is the rarest member, made only for a few years, as from 1938 until sometime in 1940. They came in three configurations: a genset, power take off (as in this video) and a marine version. They were rated at 15 hp @1200 rpm continuous. They could make more, as up to 25 hp @ 1600 rpm, but apparently these early versions were not happy at those higher speeds for long.

Speaking of, all DD “Jimmys” sound like they’re revving a lot higher than they actually are. Since they’re two-stroke engines, there’s twice as many exhaust cycles than a four stroke, so they sound just like they’re going twice as fast, as all two-strokes do.

I had a hard time finding a really good 12V-71 video, but this one is pretty good, of a Kenworth hauling 140k lbs crusher out of a quarry, with a little assist at the rear from a loader. It’s running at full speed, which is 2100rpm, at that speed it made 456 hp, unless it’s a turbocharged 12V-71T, in which case it was making 525 hp. Detroit Diesels did not have a huge jump in power when turbocharged, since they already had a mechanical blower out of necessity. In the turbo versions, the blower would cut out and the turbo took over at higher speeds.