Excessive heat due to lack of cooling or improper needle setting is what seems to stick rings, at least that is what I have seen. Not the oil or ratio used as long as it is a quality oil. I still would never run any oil at 100:1, even Amsoil recommends richer mixtures. To this point I have never had an oil related failure and currently like the Pennzoil I am running at 32-40:1. Just took apart an engine and it was clean shinny with minor deposits that wiped away.