There's just something about miniscule internal combustion engines that we love. They're always powerful for their size and they sound close to their much larger cousins. You just don't see too many installed in equally impressive little cars. Thankfully that's changing.
YouTuber JohnnyQ90 recently swapped the V-twin he has in an old RC 4x4 for a 17.5-cc four-cylinder unit with a three-speed manual transmission. It was way harder than just mounting the new engine and calling it good, though. He had to reconfigure the car's tiny cooling system, route a new exhaust, and wire everything up. After all of the hard work, the end result is awesome.
The engine itself is made by a company called Cison and costs around $1,000 without a transmission. The three-speed (plus reverse) gearbox is also made by the company and costs about $450. Interestingly, the transmission has a 3D-printed aluminum case, a good example of this stuff cheaper and cheaper to the point where it makes sense for applications like small engines or other similar mechanical assemblies.
The transmission and throttle are both controlled with servos and operated via remote control. As with any tiny off-road vehicle, the results are small scale, so not super impressive. The little 4x4 scales a curb and makes it out completely unscathed. Look in awe as it conquers that discarded napkin on the side of the road. Regardless of what this R/C car is doing, it's nice to hear a rumbling four-cylinder soundtrack as compared to the usual whirr of an electric motor.
Ultimately, this little truck is just a cool novelty. Similar to hair-raising supercars, tiny vehicles with real engines don't have much utility. They are interesting as heck though, and for that reason, they deserve to exist.
