To break in say... a 3W or DA 150, we all pretty much agree to run a petroleum based oil-gas mix before switching to a synthetic like Amsoil. (not that you need to swithc to a synthetic, but this is the hypothetical situation). We have been told to do this for a certain amount of time OR gallons. How much time or how many gallons. I've heard as little as 4 gallons, and as much as 12. Let's hear it.

Tim, I really can't imagine that you would need more than 4 gallons. The main thing that you are trying to do is seat the rings. When you determine this by the consistant amount of good compression that you are seeing both hot and cold and that the compression is no longer improving and that the rpm is no longer increasing then it is probably time to switch to synthetic. If you switch too early, you aren't going to damage your engine. It may simply take longer for the rings to seat because less wear is taking place.

My 2 cents worth,
Ken

When was the last time you broke in a weed eater or a chainsaw? I have seen a lot of hype about this and what I do is put it in the plane and fly it. What helps seat a ring is heat cycles, heat it up for a flight, then let it cool off and do it again. I also hear some people say when it breaks in it will swing a certain prop, if it wont swing a prop now, it wont swing it later. Arter a ring is seated you are not going to realize a thousand RPM increase,a couple hundred at best. I do beleive in putting enough engine in a plane so I dont have to have it wound up ALL the time, Just take it 50 to 75% the first 4 flights and then have some fun.