Watch Rob Dahm Try To Assemble A 12 Rotor Engine

Rob Dahm sits in front of a bunch of Mazda rotors looking slightly overwhelmed

Photo: Rob Dahm via YouTube

Sure, the rotary engine may be an oil-eating machine filled with Nazi-designed spinning tortilla chips that turn money into nightmares, but god, I love them. My first car was an RX-7, and while, somewhat tellingly, I haven’t owned another rotary since, I think about them often. Not as often as Rotary Stifler, aka Rob Dahm, though, and especially not since someone gave him a homemade 12-rotor marine engine to try to get running.


Yes, 12 rotors. It’s a lot to contend with, even for a rotary expert like Rob. This engine was cooked up and built by a guy, which means it has all kinds of idiosyncrasies and quirks that have to be dealt with to get this pile of parts that hasn’t run since 2008 back into fighting shape. Maybe it’s just my natural love of schadenfreude, but seeing an hour-and-a-half-long video of people organizing springs and seals and figuring out rotor timing on this one-of-a-kind motor with very little documentation is so satisfying, which is why I’m sharing it with you.

In addition to the massive organizational challenge presented by this many rotors, Dahm and company have to try to figure out what made this engine kick the bucket in the first place, then try to prevent it from happening again. This involves working with a ton of custom-machined parts, astronomical prices for even Mazda-based rotary engines and then doing some A Beautiful Mind level mathematics so that not only are all the rotors timed appropriately, but they’re also set up so that a modern computer can run the ignition and also so it won’t blow up or shake itself to pieces.

There’s a lot of moving parts. OK, well, not that many; it’s a rotary, but as a figure of speech, it works. Enjoy.