10 Most Unusual Production-Car Engines of All Time

The stats are the stuff of legend: The Bug’s 8.0-liter, 1000-plus-hp W-16 is the most powerful and complex production engine in history. It has 64 valves, four turbochargers, and enough pavement-shredding grunt—as much as 1106 lb-ft at 3000 rpm—to wrinkle God’s underwear. Its W-shaped, 16-cylinder layout, essentially an orgy of narrow-angle Volkswagen VR4s, has never been used before and likely never will be again outside of perhaps another Bugatti. Oh, and it came with a warranty.

Bugatti Veyron 16.4 Road Test

This is a once-in-a-lifetime engineering unicorn, kind of like what would happen if the Apollo space program and Ferdinand Porsche somehow jointly got the Titanic pregnant. If that ain’t interesting, we don’t know what is. (2011 Bugatti Veyron 16.4 Super Sport pictured.)

At the beginning of the past century, automotive frontiersman Charles Yale Knight had an epiphany. Traditional poppet valves, he reasoned, were too complicated, the attendant springs and followers too inefficient. His solution was dubbed the sleeve valve—a sliding sleeve around the piston, driven by a geared shaft, which exposed intake and exhaust ports in the cylinder wall.

Amazingly, it worked. Sleeve-valve engines offered high volumetric efficiency, low noise, and no risk of valve float; disadvantages were few but included high oil consumption. Knight patented his idea in 1908, and it later appeared in everything from Mercedes-Benzes to Panhards and Peugeots. The technology fell out of favor when poppet valves became better able to cope with heat and high rpm. (1913 Mercedes-Knight 16/45 pictured.)

Imagine that you’re a 1950s carmaker being pitched an experimental engine. This German dude named Felix walks into your office and tries to sell you on the idea of a three-pointed piston spinning around inside an oval box, burning fuel as it goes. It looks like a ball of fire in a bingo cage, or maybe a football knocking around in a washing machine. And not only does it run, but it’s also incredibly balanced.

The rotor itself is triangular with convex faces, and its three corners are called apexes. As the rotor spins within the housing, it creates three chambers that are responsible for the four phases of the power cycle: intake, compression, power, and exhaust. Each face of the rotor is always at work on one stage of the cycle. If it sounds efficient, that’s because it is—sort of. Horsepower outputs are high relative to engine displacement, but they suck fuel like whoa because the combustion chamber is elongated.

Weird stuff, no? You know what's weirder? It was in production until 2012 in Mazda's RX-8 sports car. (1967–1972 Mazda Cosmo 110S pictured.)

Connecticut’s Eisenhuth Horseless Vehicle Company was formed by John Eisenhuth, a New York man who claimed to have invented the gasoline engine and had a nasty habit of getting sued by his business partners. His 1904–07 Compound models featured an inline three-cylinder engine where two outer cylinders powered an unignited, “dead” middle cylinder with their exhaust gases; the middle cylinder provided the engine’s output. The outer cylinders were huge, with 7.5-inch bores, but the inner, at 12 inches across, was larger still.

Eisenhuth claimed a 47-percent increase in fuel economy over a standard engine of similar size. He also went bankrupt in 1907. Go figure. (1906 Eisenhuth Compound Model 7.5 pictured.)

Leave it to the French to design an interesting engine that seems ordinary at first glance. Famed Gallic manufacturer Panhard, largely remembered for its eponymous suspension rod, powered its postwar cars with a series of air-cooled, aluminum-block boxers. They were distinguished by unit construction—the block and the cylinder head were one casting—torsion-bar valve springs, a roller-bearing crank, hollow aluminum pushrods, and exhaust pipes that doubled as engine mounts on one variant.

Displacement varied from 610 cc to 850 cc; output was between 42 hp and 60 hp, depending on model. The best part? The Panhard twin remains the oddest engine ever to notch class wins at the 24 Hours of Le Mans. (1954 Panhard Dyna Z pictured.)

Strange name, sure, but the engine is even weirder. The 3.3-liter Commer TS3 was a supercharged, opposed-piston (each cylinder has two pistons with their crowns facing each other, and there are no cylinder heads), single-crankshaft (most opposed-piston engines have two), three-cylinder, two-stroke diesel engine.

The Rootes Group dreamed up this beast to power its Commer-branded trucks. The TS3 offered ingenious packaging, connecting-rod rocker arms the size of a small cat, and at 270 lb-ft of torque, more grunt than many larger diesels of the time.

Confused? Watch the animation here. (Commer bus with TS3 pictured.)

Think the Commer was smart? This one puts it on the trailer. England’s Lanchester Motor Company was founded in 1899. The firm’s Lanchester Ten, introduced a year later, featured an air-cooled, twin-crankshaft, 4.0-liter flat-twin driving the rear wheels. One crank lived above the other, and each piston had three connecting rods—two light outer ones and a heavier one in the center. The light rods went to one crank, the heavy rods to the other, and the two shafts counter-rotated.

The result was 10.5 hp at 1250 rpm and a remarkable lack of vibration. If you’ve ever wondered what engineering elegance looks like, the engine in this car is it. (1901 Lanchester pictured.)

Like the Veyron, the limited-production Cizeta (née Cizeta-Moroder) V16T supercar is defined by its engine. The 560-hp 6.0-liter V-16 in the Ciz’s belly isn’t a true V-16. If you go by firing order and construction, it’s merely two flat-plane V-8s sharing a single block and joined by a central timing case. This makes it no less insane. Because the engine is mounted transversely, a central shaft feeds power into a rear-mounted transaxle.

The Cizetas are rarer than honest politicians, with just a tiny number built. The true production number is a secret, of course, but one of them occasionally surfaced in L.A., where its owner revved it mercilessly prior to customs officials seizing it in 2009. (1991 Cizeta-Moroder 16T pictured.)

The Commer Knocker engine was actually inspired (if that’s the right word) by this French family of opposed-piston engines that were built in two-, four-, and six-cylinder form until the early 1920s. Here’s how it works in two-cylinder guise: Two pistons drive the crankshaft in the conventional manner. Opposing the two pistons is another set of two vertically opposed pistons joined by a crosshead. In turn, this crosshead drives two long connecting rods coupled to the crank at 180 degrees relative to the lower pistons. The opposed pistons effectively form the cylinder heads. A six-cylinder engine thus has 12 pistons and a crank with the torsional rigidity of spaghetti.

The production engines ranged from 2.3-liter twos to 11.4-liter sixes. There was also a monster 13.5-liter four-cylinder racer that was the first car to top 100 mph, driven by Louis Rigolly at Ostend, Belgium, in 1904. These crazy Frenchmen, obviously unfettered by conventional thinking, also ran a crude form of fuel injection in their earliest engines. (1900 Nagant-Gobron 14/15 hp Type C Victoria pictured.)

If the idea of your engine rotating behind you seems like a good one, then the Adams-Farwell, hailing from Dubuque, Iowa, is your car. Well, it wasn’t the whole engine rotating: just the cylinders and pistons, because the crankshafts on these three- and five-cylinder engines were fixed. Arranged radially, the cylinders were air-cooled and acted as a flywheel once the engine was up and running. Drive was taken off the cylinder assembly via a short, single chain, and the units were light for the time—190 pounds for the 4.3-liter three-cylinder and 265 pounds for the 8.0-liter five.

The cars themselves were rear-engined, with the passenger compartment mounted far forward, perfect for getting absolutely destroyed in an accident. Bearing in mind the lack of mechanical reliability in the early days of motoring, we wonder exactly how comfortable you would feel about 265 pounds whirling at 1000 rpm behind your calves. (1906 Adams-Farwell 6A Convertible Runabout pictured.)