The internal combustion engine with a flathead layout is the kind of simple but powerful design you’ll find in the Ford Model T and many other early cars. In this video, YouTuber JohnnyQ90 creates a small but fully functional example and showcases the entire project.
Where almost all modern combustion engines place valves on top of cylinders, flat heads place them on the sides. This is why some people refer to this design as a sidevalve.
The tiny engine displaces just 1.06 cubic inches (17.5 cubic centimeters) and weighs 3.31 pounds (1.5 kilograms). It runs on gas, like a full-sized flathead. There’s even a working carburetor.
The manufacturing process includes everything you would do to install a flathead machine, except the parts are much smaller. It’s like modeling a car, but in the end, you have a fully functional machine.
Piston assembly involves the vice to fit the wrist pin through the connecting rod. There’s even a small piston ring to attach.
The valvetrain is even more complicated to build. The process includes keeping the valve lifter at a certain tolerance.
After most of the assembly, the video is cut to the point where the engine has the fuel, coolant, and oil lines in place. On initial startup, the machine sounds like it’s running pretty rough. Also, one of the front seals is leaking oil.
In the end, the engine snored. His voice was reminiscent of a small grass trimmer. Unfortunately, there is bad news because the starter motor failed. Judging from the assembly process, the replacement of parts does not seem too complicated.
Kit to build this the machine sells for $999.99, but a discount for the first 50 buyers lowers the price to $799.99. This person also has accessory collection $149.99 that includes starter spark plugs, radiators, and more.
We previously saw JohnnyQ90 work when he made a mini two-rotor Wankel engine that cranked up to 18,000 rpm and sounded amazing. He also assembled a nitro-fueled V8, 1/10 scale with a pair of carburetors.
