Two Cranks, Four Cylinders...

…and eight pistons.


While it sounds remarkably like a first-time engine build gone awry, it was actually a development engine from Ford, designed and built by Eugene Farkas.
In the 1940’s, Mr. Henry Ford was experimenting with lightweight, tube-framed cars, attempting to create a structurally rigid, but overall simple-to-construct car. And what better to power such a car than a very unique powerplant. Understanding Ford’s mindset of simplicity is key in the development process (even if this seems a bit extreme for only seeking to eliminate some engine vibration!). You see, the world was changing, and getting more and more complex. Ford wanted to retain the simplicity of the Model T, but create something powerful, efficient and reliable to work in then-present day America. The four cylinder engine illustrated this simplicity, but it lacked the balance of a V-8 (far less torsional vibration, even in a solid-mount configuration). In his quest for a vibration-free engine, this twin-crank eight was born...

Granted, it’s technically a four cylinder, but with two cranks and eight pistons, each moving in the opposite direction on combustion, thus balancing either side of the assembly. The engine had an overhead-cam, with a chamberless design (leaving the the actual combustion chamber in the block), running 1.5-inch valves. At 83 cubic inches (2.25-inch bore, 2.625-inch stroke), and running such a short stroke, this design would’ve been great for some high-RPM action, but, sadly, suffered from poor crank design (the billet cranks had no counterweights on the cheeks, thus exposing the center mains to some heavy abuse, consequently deforming at higher speeds). The cranks, incidentally, were geared together via herringbone gears (a pair each of left-and-right-hand helical gears per side), which were as quiet as a standard, single helical gear, but suffered no thrust issues. A large idler at the rear of the assembly acted as the flywheel, with the pressure plate (from a V-8 60) bolted to it. Furthering the quest for low vibration, the driveshaft speed was low, as the idler tgransferring power spun at roughly on-half of engine speed. A simple design engineered to arrive at the solution!

Another interesting fact is that this engine was constructed mainly of cast iron (aside from the aluminum oil pan). At the time, almost all of Ford’s experimental powerplants utilized aluminum. This considered, the assembly only tipped the scales at around 260 lbs, and looked pretty slick, too:



Looking back, a simpler solution, such as rubber motor mounts, isolators, etc, may have been the more logical, stop-gap answer, but Mr. Ford had sought perfection in design, and running a solid-mount would have reinforced that notion. Besides, it was a pioneering effort like this that makes for such a great story…

As always, I invite you to check out my website at www.problemchildkustoms.com for more stories, and plenty of hot rod and custom car design.