I pulled my motor a couple months back and pulled the heads last month. Get a call from my local dyno shop where I do all this work and my bud tells me that one of my pistons does not look right.

So I get there last night and interesting enough, he was right. You can see a good portion of my top ring fully exposed. The piston was coming apart somehow.

I was going to just use them again, sorta laughing at all you guys with forged pistons, thinking I was saving a buck when you spent good money of forged pistons when you didn't need to, well, I will be joining your ranks again this season.

Still ran the times in the sig with this problem, crap exhaust, and just started to tune the thing.

 

I run the KB's & ran the times in sig on a 150hp n2o. I was planning on working my way up to 200hp\225hp on a two stage setup . Who put the engine together? Did they gap the rings to KB's tolerances. Even a lean condition can bust these pistons if the rings aren't gapped correctly. Makes me wanna rethink my game plan. Stock hypers can usually handle that much?

 

sounds like the rings "butted" and broke the top of the piston, There is a ring end gap chart in the box with the pistons and needs to be adheared to, too little end gap rings expand and butt together and expand further pushing the top of the ring land. "Hyperslugs" as you call them deflect heat into the rings causing them to expand, thus ring gap is VERY important in these pistons, trust me I've been down this road. The pistions are veary durable with the correct ring gap.

 

I built that engine.

I gapped the rings @.060 matched to each cyclinder bore.

The engine ran on the dyno 11.0-12.0 AFR.

Rings were $200.00 tool steel top ring.

I was planning on running 150 shot hence the ring gap.

It might have been a bad piston...being that only one crapped on me.

Something I forgot to mention, my motor overheated twice due to my elec wp dying. But, I build loose motors so if it did cause a problem, why not all the pistons?

I planning on making around 430-450 rwhp and then spray a 100 shot on it and question the durability of the KB hyperslug.

 

If you gapped the rings correctly (sounds like you did) then maybe you got a bum piston, sounds like that might be the case because you only have one bad hole.
I would probably go forged sence you hav to pull it all apart.
I talked to a couple of my machine shop friends and they quit using them cuz they are heavy and they are prone to breaking the top ring land. I have a set in my 11sec monte and they have been fine, but i hear I am in the smaller %age. They also said that they are prone to breaking if you overheat. Good luck