Probably the number one breaker of rings is detonation (pinging). Excessive/frequent overheating can weaken the rings, especially old high-mileage rings which can lead to breakage. Lousy fuel? Well yes...if it causes detonation. Poor timing can cause detonation, but you can still get it with the timing spot on in many cases, depending on load.
Last edited by TigerDan; 03-14-2007 at 08:38 PM.