cylinder 3 spark!?

[Driftapparel.com]

Wow this is crazy! Anyone know what it could be?

So when I am drifting or just spinning messing around if I boost too much (it seems) my cylinder 3 spark plug gets smashed and I loose the cylinder until I pull it out and re-gap it. It's all pitted too as if something is hitting it. The wierd thing is that it is only the 3rd spark plug back!

Any input would be greatly appreciated

Thanks
-Brett

[AllMotorS13]

well...something's probably hitting it, haha. what type of plug are you using? anything under a free rev, or is it just under a load? how much boost?

[Driftapparel.com]

I am using the stock NGK spark plugs ill post the code tonight after I get home. I was using wrong spark plugs before and it was doing it all over the rpm range now that I have the right ones in its only under boost. Stock S13 redtop SR20 boost.

Thanks alot

[AllMotorS13]

i believe they should be bkr6e for a relatively stock SR. not sure why it would only mess up #3. have you tried actually looking through the spark plug hole into the cylinder?

[HalveBlue]

Check the top of the piston for any marks that would indicate the piston hitting the spark plug. Also check the threads for the spark plug hole for any damage.

Perhaps the piston rod isn't seated correctly on the crankshaft? Bad bearing? Loose con rod bolt?