I made a 4 cylinder car engine to look like a Honda VTEC engine. I call it a LEGO LTEC. Has more power than a civic :P
I used the shape of the cylinder head for sound reverberation and a large plate that the air from the pistons hit to make exhaust noises. No valves as it would of slowed down the motor. This is what I call a sound engine, not a scale model of the workings of an engine. Can be disassembled like a real engine.
Video quality might suck, would of took all day to upload 800mb
See pictures of the engine on my MOCpages:
http://www.mocpages.com/moc.php/421667
Also support my 1970's Racecar on LEGO Ideas!
https://ideas.lego.com/projects/121162