Originally Posted by adianaty

Don't get me wrong, the ring gap is certainly not right and needs to be increased. But this damage is not initiated by ring gap alone. Ring gap in itself will not melt the piston or cause the land to break off. You have to have excessive cylinder pressure and heat i.e. detonation. Here is Mahle's own description of the failure. See page 20.

http://www.scribd.com/doc/47784054/M...ushings-Manual

These hypereutectic pistons are like glass when they are loaded up under detonation and are unforgiving. e55amgrockets car made 619whp so let's assume that is over 700hp's but he did it with some excellent race gas that takes some work to get to detonate. If it was gaps alone, he would have had piston failure pushing that much through his motor. I've seen plenty of the hypereutectics go in other platforms and truth be told, they always blow up pretty fantastically and never have light wear like a forged piston. My only point to anyone is, if you are going to go so far as open her up to increase the gap, spend the extra $1500 for the forged pistons since I wouldn't reuse the rings anyway. Mahle's run $1950 for pistons, rings, and pins. Call me ridiculous but I wouldn't tear my engine apart and put the stockers in considering for $1500, I would NEVER have to worry about it and have a fully forged bottom end. The original purpose of the thread is spot on. Going into the motor before damage on these cars makes a tremendous amount of sense to fix both the ring gap and in my opinion, replace pistons with forged units early if you are really going to push it.

Originally Posted by Forrest Gump 9

831/932!!! Damn, that's a healthy dose of laughing gas.

Originally Posted by e55amgrocket

I couldn't agree with you more. I've made well over 600hp on a motor with 120k miles. I also put down 831/932 the night before playing with the nitrous before the RTR pulley ate the crank and again not a problem with the piston/rings. Im also running pretty aggressive timing and didn't take any timing out for the nitrous and it was completely fine. 99% of that was due to the 120+ octane fuel and the other 1% was knowing where to stop with the timing. The guy that is trying to repair my crank was amazed that a stock car had a crankshaft like we do. That's tells you a lot and the rods are extremely strong to being a forged rod with a relatively short stroke. Timing/detonation is what causes the ring land failure and melted pistons. Race gas will let you be a lot more "reckless" with the tune but only to a certain point. I'd much rather have a very safe street tune and give up 20-30hp than take a chance on broken pistons.

Originally Posted by SterlingE55

Great Jehovah's Witness!