and the plug looks like this!




I haven't torn it apart yet but I have a pretty good idea what it looks like with small flecks of alum. on the plug. So now what do I do next? I have a nice bunch of parts. What would you do with my parts? What shortblock would you apply them towards? If I go too big, my cam, heads and headers will soon be undersized. This one was supposed to have 27k miles on it out of a '04 GTO. And it looked it too..... BTW, NA all the way!

 

I'm guessing the ringland came apart....

 

What causes this? I haven't overheated it. Did it go lean? I did have some oil mist from the PCV. Did the oil cause it (detonation)?

 

I can't see the picture at work because of picture filters. Usually, no compression = ring failure, ring land, or destroyed pistons. The usual cause of this is detonation.

 

Do a leak down as your first step.

Did you drop the plug or was it closed like that?

 

LOL, a guy at work said, "you dropped that plug, right?" I showed him the nick on it. It has been hit by something... ie, chunk of ring or piston. I'm positive with what I've seen that I will hear air come whistling out of the dipstick tube. I poured some oil in the combustion chamber and came up with 25psi vs the Opsi I got with no oil.

 

That's a fair indication that you have ring problems and while I don't see how a bent valve would do what you're seeing, I would want a little more proof before I decided - take the heads off or drop the engine.

 

Yeah, I will drop the engine and pull it apart on a stand before I start ordering anything. I guess I should have added that the rest of the plugs looked like new so the excessive fouling would have been proof I didn't drop it after I pulled it out.

 

Does the stock LS1 PCV system create enough oil mist to detonate and cause piston failure? I'm trying to make sense of this so it doesn't happen again. I will have a catch can next time but not sure that is what caused this....

The #7 intake runner is dry. The rest were plenty oily of course. So that means #7 hasn't been sucking for some time. I really think this piston has been dead for a long time.