The Freevalve engine impressed us mightily when Christian von Koenigsegg showed it to Jalopnik on a 2014 drive in Sweden. Today, the concept is alive and well, and Wesley Kagan, a “builder” in the best traditional sense, has applied the technology to a 6.5-horsepower Harbor Freight Predator engine.
In the video, Kagan walks us through the entire design process and eventually through a test run. The project began with Kagan’s realization that the cost of a custom camshaft for his PorscheCart engine would run to thousands of dollars.
Kagan asks the question: How do you drive an engine’s valves without a mechanical device? One solution to eliminating hardware like camshafts, followers, rocker arms and such may be Freevalve. Kagan’s adaptation uses pneumatic force rather than electromagnetic, but he’s working on two — hopefully — interchangeable designs for his project.
The intrepid gearhead put on his Doc Brown lab coat and said “where we’re going, we don’t need cams.”
Kagan gutted the Harbor Freight engine, threw out the rocker arms and replaced them with his homebrew version of the Freevalve system, which uses a Hall effect sensor, an Arduino board and air-pressure solenoids to drive the valves.
The entire process was not without some hiccups, and the build itself proved hazardous when a pressurized retainer pin shot out of the assembly with enough force to bury itself in Kagan’s drywall. But the project goes on and modestly succeeds, impressing even its builder, who simply exclaims “Wow, that’s incredible.” How many times have we said the same after a shoddy job in our garages?
It’s a work in progress, certainly. The Harbor Freight/Koenigsegg tech engine does not accelerate at the moment. But all projects are in the test-bench stage at some point. We can’t wait to see what Kagan comes up with next and hope we see a bigger, more impressive version of this on the road in his PorscheCart.
The project is open-source, and the video includes links to project files for those of you who would like to assemble your own Freevalve engine. Even if this is not in your wheelhouse, you can use this project to get you in a wrenching mood. Channel that energy and get into your garage this weekend.