Do piston rings rotate and if so how much? ........ I know 2cycle rings are

[Qikbbstang]

prevented by a pin so they will not get an end stuck in a transfer/exhaust port. But on an auto engine not sure how much or even if there is anything that would make em spin

[jayb]

I assume that they rotate through 360 degrees as the engine is running because they are never in the assembly position when the engine is taken back apart.  How fast would probably depend on ring groove clearance, size and design of the ring, cylinder wall prep, etc.  I don't know of a rate of rotation, if that's what you are asking...

[chris401]

That has been mentioned at work. If a compression test (cylinder leak down test) show low in test cell they will run longer and recheck. Rings rotate and give accurate reading.

[GJCAT427]

Yrs ago someone did a vidieo about this subject. As I recall they proved that the rings do indeed rotate, It was avery detailed report, showing before and after pictues of the ring location in the clyinder wall.

[Barry_R]

They do rotate - fairly slowly if things are working properly.  Sealed Power (and others) have run tests on this.  If I recall correctly they only averaged around 12 RPM in the Sealed Power testing with a wide range of variability.