It’s amazing to me to see just how far Legos have come since I remember playing with them as a kid back in the ’70s. Yes, I’m old. But that doesn’t matter. What does matter is that today, you can build an engine from Legos, then power it with an electric motor to see how it operates, then take it apart to inspect it. It’s nerd-dom at its finest.
In this video, YouTuber legomaniacman shows off how the dual-overhead-cam, V8 Lego Technic engine runs when powered by a 9-volt RC motor. The Technic series of Lego parts is so far advanced from the unrealistic parts I remember snapping together as a kid, but it’s also an amazing way to turn your child into an engineer before they are even into high school.
He’s got this thing geared up to run about 2,000 rpm with the variable-speed RC motor, and the clatter of the gear-drive timing set combined with the dyno drive system—along with the simulated dyno cell—makes for an entertaining video, especially as he winds it up and down the RPM band. While it’s running, he pops off one of the cylinder heads so we can check out the pistons in action. As it winds up, the pistons are moving quickly enough that they simply become a blur.
Think about it like this—that little plastic crankshaft is turning at 33.34 cycles per second. Sadly, we don’t know what the stroke is, so there’s no way to calculate the piston speed, but it’s quicker than the naked eye can see.
Quite frankly, with the loose manufacturing tolerances of the gearsets, I’m surprised this thing didn’t rattle itself apart in the first 30 seconds of runtime. It sure is fun to watch it whirring away, though. Enjoy!