I"m running a trick kit on my 2002 5.3 and I finally had time to actually tear the engine down again. I'm running about 7 lbs with a black bear tune. Last time around, a bad batch of fuel caused a hole in #7 piston. I went through the whole thing and put a set of wisco pistons in it. About 3000 miles later she went to knocking. I assumed that I had bought cheaper bearings and spun one. Once I got it apart, the #2 piston was trashed. This time the skirt was wore about a sixteenth of an inch and the cylinder wall was scored pretty badly. Needless to say, I won't buy wisco again. I don't know if the piston clearance wasn't high enough or what the deal was but, they were supposed to be ready to go and boost capable.

What would you guys recommend I try next? I was thinking about putting 6.0 heads on it with stock gm pistons or maybe even dropping a 6.0 in it instead. I haven't really decided what I want to do. My end goal is around 450-500 horsepower. Anyone have any ideas?

 

Wow. Talk about a stroke of bad luck! I think you'd be happy with a stock 6.0 with a cam and turbo mods to the motor.

 

I was kind of thinking that a 6.0 with about 6-7 lbs out of my 70mm turbo wouldn't be bad...

I guess I'm not 100% sure how well that turbo would mate with a 6.0 though.

 

Black bear tune huh? That a live tune I hope? Most of the time these Pistons are damn strong. Sounds like it's something more than just breaking parts. There is something else missing. These Pistons can hold up to a ton of abuse. 7lbs isn't enough to make them pop without other factors.

 

Yeah I'd have to agree not sure it was a piston issue especially at only 6-7lbs... I have ran countless amount of nitrous bottles (150) and around the same amount of boost as you without issue as well as others here on this site. What plugs are you running?

 

Get rid of that garbage black bear tune. A tune will make or break an engine. And looks like it broke yours, twice.

 

Tell us about your fuel system.

 

#7 both times? Sounds more like a fueling issue than a bad set of pistons.

 

He said the second time #2 was messed up. Could be a combination of things.

 

I think everyones first reaction here is to look at factors that were present in both situations... Mail order tunes can be hard, especially when you deal with the volume that BB does. How do you KNOW it was bad fuel? That sounds kind of like an excuse for a tune that was not 100%... especially on only 7# boost.