ORIGINAL: earlwb
On a 4 stroke engine, it does not matter.
On a 2 stroke engine you place the ring gap in between 2 or the ports on the engine, so that the end of the ring doesn't catch in a port.
Earl, it depends on the two stroke engine. The Fox .74 Eagle IV for example has a free rotating ring which will not catch on a port. When I first got the engine, I noticed that the gap could be seen through the exhaust port and called FOX thinking that may be a problem. They explained that the ring is free rotating and in fact will rotate as the engine runs.
Bruce