Do piston rings rotate on the piston?

[Dominik]

In his book Power Secrets Yunick elborated around the gap and power loss, and 20 years ago when I read it, lost me.

It relates to a more than linear (cube?) loss depending on the gap. I shall dig out that book.

I did, and he also wrote about rings spinning in the grooves (or was is Bill Jenkins?):


Page 50, center column
Smokey Yunick's Power secrets

"If the head gaskets, the rings and the valves are all sealed tightly, there should not be very much leakage when the the high-pressure air (from a leak-down tester) is fed into the cylinder. It is not possible to gain a 100% mechanical seal in the cylinder, but if everything is in top notch condition, there should not be more than about 4% leakage.

..., if the average is over 8%, you don't have an engine,...

This doesn't sound like much to worry about, but you have to remember that only 1/3 of the heat energy (pressure) developed by each cylinder is actually going to push the piston down. So, if 8% of the cylinder pressure is leaking away, you are theoretically losing 24% of the recoverable flywheel horsepower."