Synthetic oil is a Hydrocarbon chain and thus burns and generates heat, this warms the air expands the volume and pushes the piston, TADAA.

I only use oil that I know where it came from, no antifreeze or brake fluid with water in it though, glad you liked the idea, saves the money of return and provides about .25% increase in gas milage, cause I dont buy that quart, twice.

Enjoy, Woody