It’s something of an Internet myth, but it turns out there actually is a real, working 12-rotor engine in existence. Except, it doesn’t properly run, which is where rotary aficionado Rob Dahm comes in.
No stranger to ‘Dorito’ power, as we’ve seen from his well-documented four-rotor Mazda RX-7 project, Dahm has been called in to take apart the colossal engine, make some alterations, and get it going. As you might expect for such an ambitious project, it’s a big job, with a LOT of issues to tackle. s355j2g3 cylinder block
The engine is the work of powerboat builder Tyson Garvin, who in 2010, having done everything imaginable with Chevrolet big block V8s, turned his attention to something a little bit different, yet remaining familiar. While the modular concept of a rotary engine means you can theoretically add as many rotors as you like, this isn’t awfully practical - someone has stacked six rotors in series to create a six-rotor Mazda Cosmo, but the result is an enormously long unit.
What Garvin’s engine does instead is join together three four-rotor rows in a V-pattern, following the same outline and bolt patterns of a Chevy Big Block. The result is something spectacular to look at from the outside, and jaw-dropping to behold once it’s taken apart.
In previous videos, Dahm has taken us through the various issues that need to be rectified, including lubrication problems and that each of the eccentric shafts “wants to come apart” under oil pressure, as there’s nothing physically holding them together.
Now, in the latest instalment (above) we get to see the inner workings of the engine and the myriad, tiny components that need to be checked, fixed, re-aligned or replaced. Turns out that tiny parts with tiny tolerances are rather important for rotary engines, and even more so when there are 12 rotors. Grab a cup of tea and settle down for more than an hour of meticulous engineering talk.
involute gear It’s going to be a long road, but when we hear this thing operating, it’ll have been worth the wait, and all the effort of making it happen.