Engines Exposed: The Wankel Rotary Shouldn't Work But Somehow It Does

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We take a crack at the mysterious engine made famous by Mazda.

A rotary owner's favorite question undoubtedly is: "How many cylinders does this car have?" A light scoff would then preface the inevitable answer, "none." An argument might occur, but as the rotary owner knows arguments are futile, especially when talking about how many cylinders reside in a cylinder-less engine. However despite their pride rotary owners may not fully understand exactly how the engine works, or more specifically, don't admit that it just shouldn't work. The rotary design basically got its start back in airplanes that flew during WWI.

That engine the planes used was just a circle of cylinders rotating. The modern rotary as we know it was developed by a guy named Felix Wankel, and his design was later adopted by a certain Hanns Dieter Paschke. Then some stuff happened and now someone owns the design. The Wankel rotary can be found mainly in Mazda cars, including some of its very old trucks. Of course the RX-8 and RX-7 immortalized the engine. Let's talk about the design itself though. There are no cylinders, true, but the Wankel rotary does operate on internal combustion and is still a four-stroke. And it is still completely maddening.

After you understand how it works, you'll be astounded as to... well, how it works. You know what? It would be so much easier to show you.

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Is that not the most insane thing you've ever seen in your life? Now you understand that from looking at it, the obvious conclusion is that it just simply should not work. The engineering required is so precise; there is no room for error. At least with a cylinder engine if it's not getting compression then it's possible, in theory at least, to get some thicker piston rings. With the Wankel, if there is just one millimeter off the engine is no good. That's why so many people just buy another rotary if theirs breaks. They don't bother fixing it because there's a long shot it's going to work after being fixed anyway. So why use one at all? There are big big pluses to using a Wankel rotary. For starters, it's extremely small.

The engine in a '80s RX-7 is light enough for someone to pick up with bare hands. If you think about it there's not much to it. There are no pistons, rods, camshafts, crankshafts, no block...there is only housing. See that thing pushed up against the firewall? With the alternator in front of it? That's the whole engine. It's really quite astounding. The other upshot is that it's got low compression which makes it perfect for turbocharging. Mazda didn't miss that memo, as the last generation RX-7s came twin-turbocharged from the factory. There is one weakness with the Wankel and that is what's called an apex seal, which is what seals the rotor housing together. It's not any fault of the design, it's just a bad seal and that's the frustrating part.

Actually, there are a few more downsides as well. The engine has a lot of torque, so it can guzzle gasoline if you're not careful. That's also because it uses what are called oil squirters. The Wankel delivers oil to the fuel in order to help lubricate the seals, which is also where the misconception that rotary engines burn oil came from. This engine has so much potential, it's a real shame that it only saw a few cars in its short life. The final car to get the rotary was the RX-8 and by the numbers, that engine isn't anything to laugh at. Maybe not all hope is lost for the rotary, at least if the RX-Vision concept is any indication. Hopefully a new RX model will come alongside a new Toyota Supra. Let's keep the dream of the '90s alive!


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