If we had a nickel for every automotive CEO who seems fixated on the letter X, we’d have two nickels. Which isn’t a lot but, well, you know how the meme goes. The history of auto giants pushing weird ideas through, to the benefit or detriment of the company, goes back about as far as the combustion engine itself. One of Henry Ford’s most interesting was the X-8, an eight-cylinder engine that he’d hoped would give Ford a ten-year advantage over its competition.

That didn’t exactly come to fruition, as you might have guessed. The V8-powered Mustang GT is proof. But later developments would prove the X-8 was actually ahead of its time. Here’s what’s worth knowing about Ford’s innovative eight-cylinder engine.

A Look At The Ford X-8

The Ford X-8 engine was essentially a pair of V4s paired on a single-plane crankshaft making one throw for the front cylinders, and one for the rear. The V4s were configured so you had one V pointing up and another pointing down, hence, the X configuration.

Ford’s team experimented with water-cooling and overhead-valve models, but they ultimately went with an air-cooled L-head layout, with a fan situated at either end of the crankshaft. This was intended to eliminate the need for a radiator, freeing the body designers to play with more sleek profiles.

Ford applied for the patent for the engine in 1920, but it wasn’t approved until 1927. Design was handled largely by Eugene Farkas, a Hungarian-born, Royal Joseph Technical University-educated engineer who had made a name for himself designing Ford’s Model T and Fordson tractors.

Is It Possible To Drive One Of These Things?

Double-check the specs we’ve listed above, and you’ll notice we don’t have any data on horsepower, torque, zero-to-sixty, or fuel economy. That’s because this engine never actually made it into production.

The X-shaped configuration introduced heating and lubrication problems that even Ford’s best minds couldn’t solve. An estimated two dozen prototypes were built in hopes of creating an X-shaped engine that could reliably power a passenger car without overheating and breaking down, but they never quite got there. The Ford Model A was initially designed to house the X-8, but would eventually debut on December 2, 1927, with a conventional 200.5 cid four-cylinder under the hood.

The X-8 was generating friction, not just under the hood, but in the company, as well. It took pretty much all of Ford’s closest advisors to talk him out of this crazy X-shaped engine idea, and he finally dropped it in 1926. When the patent office finally got back to him a year later, it must have felt like adding insult to injury. But, the X-shaped engine did not die out with the X-8, it just wouldn’t be Ford to finally push the concept through to production, and these engines wouldn’t find their way into passenger vehicles.

This is where Henry Ford proved to be a few years ahead of his time. With World War II just around the corner, the X configuration would soon turn out to be very useful in military applications.

Rolls-Royce built a 42-liter X-24 aircraft engine from 1939 to 1942, known as the Rolls-Royce Vulture. This motor was made by pairing a couple of V12s, resulting in a power output of around 1,450 to 1,550 hp. General Motors built a pair of X engines for naval ships. The first, the 16-184, turned out to be very effective in submarine chasing boats. The second, the 16-338 built in 1944, was less reliable.

The most recent iteration of the X configuration concept would be the ChTZ Uraltrac 12N360 X-12, launched in 2015 for Russian Armata tanks. The tank engine cranks out somewhere between 1,500 and 2,000 hp.

Pre-War Engines

The idea of putting an X-shaped engine in a passenger car may seem kind of ridiculous today, but remember, this was the anything-goes pre-war era. We were still figuring the whole “horseless carriage” thing out back in the 1920s, so you saw some really wild experimentation, with automakers racing to develop something that would give them an edge in this new industry. Here are some of the most unusual examples:

Gobron-Brillié Opposed-Piston Engines

Gobron-Brillié was a French automaker founded in the late 1890s, with their flagship engine, up until 1903, being an internal-combustion motor with two opposed pistons in each cylinder. The two pistons would spark combustion by coming together in the center, like pinching your finger and thumb. The engine was mounted at the rear, and the automaker was producing around 150 cars each year in the early 1900s.

Gobron-Brillié would expand upon the opposed-pistons concept with a pair of four-cylinders producing up to 60 hp, and an 11.4-cylinder six-cylinder producing up to 75 hp. Gobron-Brillié would stick with the opposed-pistons idea up until 1922, when the automaker finally caved and built a conventional 1.5-liter cylinder, which sold poorly, and Gobron-Brillié would file for bankruptcy by the end of the 1930s.

The Spinning Adams-Farwell Engines

The Adams company built a three-cylinder engine with a spinning crankcase and cylinders, with the idea being that you wouldn’t need a flywheel, since the rotating engine components would act as their own flywheel, and you wouldn’t need a radiator, since the design would be air-cooled. The engine was rear-mounted, with the limited-production engine making it into a limited production run of 20 to 25-hp Adams-Farwell Model 6s for public sale.

As weird as the engine was, the car itself was strange, too. It was a “convertible,” but the roof stayed where it was. The part that converted was the driver’s bench seat, which could retract and form a splash board in poor weather.

In 1906, the car was renamed the Series 6, and the engine was upgraded to an 8-liter, 45-hp five-cylinder rotary. A 50-hp Model 9 with an innovative four-speed transmission would launch in 1908. The rotary engine still exists, in concept, today, with brands like Mercedes, Audi, and Chevrolet occasionally experimenting with the design, but you won’t find any new production cars in this bonkers configuration.

The Still-Impressive Doble Steam Engines

Steam-powered engines date back to the 1600s, at least as far as we know. They became a commercial product sometime around the turn of the Century, with the most iconic probably being the Doble steam car. Developed from 1909 to 1931, the Doble was noteworthy for its fast-firing boiler and electric starter. The 1924 Series E model was known to run for up to 1,500 miles on a single 24-gallon water tank, and more recent tests of existing Doble cars see them running at speeds of around 120 mph.

The 1925 Doble E-20 could produce around 150 horsepower, and would operate much like a steam engine in a train. The electric starter would spark the kerosene fuel, boil the water, pushing the superheated steam through the double-compound engine to drive the rear axle of the car. Steam engines fell out of favor with the proliferation of combustion power, but mainstream brands were still creating experimental, performance, and one-off steam-powered vehicles well into the 20th Century, with General Motors having created a steam-powered Chevelle and Grand Prix in 1969.