If debris went out the exhaust, it would wind up inside the cat.

 

I can't really tell from the first picture but it almost looks like cylinder 1 was experiencing detonation.

Can you take a better picture of the plug? Mainly the ground strap so we can look closer

 

I'll try and take some close up pics of mine, cause same thing happend to me, except on all four. I think there might be a bad batch of Iridium plugs out there where the ceramic insulators were not properly sintered. The insulator appears to have turned to dust.

 

Well, here is a picture of my four plugs. I pulled them after the dyno runs and this is what I found.



There was absolutely no sign of detonation during the dyno run. And the datalog of the knock sensor confirmed this. I replaced the plugs with copper core ones and the car is running fine. I have never seen insulators disappear like this. I can only assume that there is a batch of defective Denso plugs out there. I'll pull the head and check out the internals, but only after I get my spare block and head built, and that won't be for another 8 to 10 weeks.

 

fperra,
That's pretty shocking I'm assuming I had slight detonation as I could occasionaly hear light ticking near redline(sounded like pins dropping on glass) I'll be doing a compression check soon. I may even check the valve clearances too. I already have the ems on order as the Vortech electronics are just a band aid

 

I recently installed Denso IK-24

 

Car still runs fine. I Boroscoped the pistons and could see nothing abnormal. Anyone else have this problem with Denso plugs?