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Pop the hood of any modern car, and you’ll find a similar sight. Four, six, or eight cylinders, a starter, an alternator, and a handful of other recognizable bits and bobs. If you see an engine, even one that isn’t in a car, there’s no mistaking it for what it is. That wasn’t always the case, though. We’ve been building engines for over 100 years, and they’ve changed dramatically over the decades. Let’s check out some of the most unusual engines of all time.
Dating back to 1885, one of the earliest automotive engines only had a single cylinder. Surprisingly, it used the same four-stroke model that you see today but had one cylinder located beneath the driver’s seat. Easy to use, easy to maintain, and inexpensive to manufacture, these single-cylinder engines only generated around two horsepower. Nothing like the power that we see out of today’s engines!
The V-twin is perhaps the father of our modern v-configuration engines. These two-cylinder piston engines were the first where multiple pistons used a common crankshaft while configured in a V-formation. These first started appearing in the 1920s for early turn-of-the-century car models. You can still find them today in limited applications such as in the Morgan 3-Wheelers.
We’re not talking about the horse, though the concept is nearly as strange. This four-cylinder engine might not seem like much at first glance, but instead of a straight 4-cylinder engine, the pistons sit in a two-by-two grid. Each set of two pistons would also use a single connecting rod in the shape of a V that would bend and flex as the pistons moved up and down. It looks as strange as it sounds, and while it might have been a great cheap alternative to the Model T back in the day, it’s not a viable option today from an engineering standpoint.
Who needs pistons when you can use a round combustion chamber and one oddly-shaped triangle attached to your crankshaft? The Wankel rotary engine technically has three combustion chambers that are constantly moving. One acts as the intake, one acts as the combustion chamber, and the third acts as the exhaust chamber, regularly cycling fuel in and out of the engine. There are no new cars with rotary engines as of 2021 though there are rumors that Mazda might bring the design back as a range-extender for their hybrid electric vehicles.
The Boxer Six
When you think about an engine with six pistons, they usually come in one of two configurations — straight or V. The Boxer six takes it a bit further, flattening out the V-shape into a flat square with three pistons on either side. It sounds strange, but it is a very well-balanced and quiet-running engine. The flat design also gives the engine a lot of contact area, meaning you can air-cool it instead of using a radiator.
More is better, right? Well, that must have been the thought process behind the invention of the H-16. This monstrosity of an engine has sixteen cylinders, with two lines of eight stacked on top of one another. Each set of two pistons is attached to each crankshaft. They generate a lot of power but also have a lot of problems. They even have a history of blowing up during races!
The Napier Deltic
If you thought the Wankel engine’s triangle-shaped piston was strange, wait until you see the Napier Deltic. Six cylinders are attached to three crankshafts in a triangle configuration, with each set of two pistons sharing a single combustion chamber. These were two-stroke engines, rather than four, making it simpler to construct because there was no need for intake and exhaust valves. We might see more Napier engines today, but the company was bought out after WWII and switched to making things like turbochargers.
The Napier Lion
Twelve cylinders might seem easy. All you need to do is squish together two inline sixes, and you’re good to go, right? Not if you’re an engineer from Napier. The Napier Lion is a W-12 engine — three 4-cylinder engines arranged into the shape of a W. While the W-Style engine isn’t exactly unheard of. You’ll find a 16-cylinder W-engine in a Bugatti Veyron or Lamborghini Aventador. A car equipped with two W-12 lions broke a land speed record and became the first vehicle to exceed 350 mph.
If you thought W-shaped engines were weird, wait until you get into the radial. This unique design looks like a starfish with five pistons all connected to the same point on the crankshaft, each with its own combustion chamber. They don’t need to have five cylinders necessarily, but they almost always have an odd number of cylinders. It was more popular on aircraft than in vehicles and fell out of popularity when we switched to turboprop aircraft engines.
The Wasp Major
Odd-numbered cylinders aren’t totally unheard of, though you’ll usually find them in even-numbered pairs. The Pratt and Whiney Wasp Major threw sense entirely out the window with four banks of seven cylinders each for a total of 28. This massive beast could generate upwards of 3,500 horsepower, or over 4,000 once they went totally over the top and added turbochargers. You definitely won’t find this on a highway near you.
What Unusual Engines Are the Most Unique?
Which of these engines do you find most unusual? We’ve come a long way since the one and two-cylinder models that launched the entire automotive industry, but there are still some limits to what we can — and should — do with a car engine. These 10 unusual engines take imagination to the next level.