Anyone who has ever seen or driven a car, probably knows how an engine functions, but have you ever wondered just how small they could get? If so, then wonder no more as we’ve rounded up seven of the world’s smallest running engines for your viewing enjoyment, like the V12 above. Continue reading to see more.

7. Miniature V8 Engine

For non auto enthusiasts, a V8 engine is essentially a V engine with eight cylinders mounted on the crankcase in two banks of four cylinders, in most cases set at a right angle to each other but sometimes at a narrower angle, with all eight pistons driving a common crankshaft. This miniature engine may look small, but it’s fully functional, though the only real practical use would be in miniature vehicles.

6. Tiny 4-Cylinder Engine

Built by George Luhrs, the “Quarter 4-Cylinder Engine” is touted as the smallest of its kind. It took him approximately 600-hours to complete and no details were spared during the build, as you can see from the images above. Hopefully, we’ll get to see this installed in a mini vehicle sooner than later.

5. Papercraft V8 Engine

This fully-functional V8 Engine was made entirely from paper by Yeesjob, with the exception of its internals. It sports many moving parts, including a compound crankshaft, a rapid cooling fan, and a complex compound gearbox etc. The engine is powered by 2 x 1.5V D batteries and weighs 6.6-pounds.

4. Air-Cooled 4-Stroke Mini V12 Engine

A A V12 engine is basically a V engine with 12 cylinders mounted on the crankcase in two banks of six cylinders, usually but not always at a 60-degree angle to each other, with all 12 pistons driving a common crankshaf. Despite it being designed for R/C models, this 4-stroke V12 engine is touted as the world’s smallest. Featuring a 21mm bore, 87cc displacement, air cooling, and two camshafts.

3. LEGO V8 Engine

Yes, an auto enthusiast has built a working V8 engine using just LEGO parts. This tiny engine peaks at a maximum of 1780 revolutions per minute, which was made possible by adding timing gears in the rear to prevent torsion in the crank and cam. Currently, it’s running in a double cam setup.

2. Smallest V12 Engine in the World

Sure, you can’t stick this tiny V12 engine in a car, but it’s fully capable of running when powered up. In addition to the inspiring movie music in the video preview, you’ll see that it’s “constructed with a combination of stainless steel, bronze and aluminum; the finished product runs off of compressed air and has a displacement of 12 cubic centimeters.”

1. Smallest V8 Engine

With a displacement of just 44cc (3/4″ bore and stroke) and measuring just 5-inches in length, this tiny V8 engine is touted as the world’s smallest. Even more surprising, the only things not made by the creator of this engine are a few standard parts, the OS carburetor, and ME8 spark plugs.