Beretta.net

I have a 90 gt with a 3.1, last week when coming home from work when the #6 cylinder spark plug was blown complety out of the head taking the threads with it. Has anyone ever heard or have this happen? any ideas on what caused it, i have a couple of ideas.

very high compression would cause this. thats all i can think off

Im thinking it was over tightend if it pulled the threads out.....

Jeeze that is strange!  Are you 100% sure that's what happened?

-Jason

Yea I have stripped numerous spark plugs, but never taken out the threads on the head.

This is odd.

Maybe detonation, but very unlikely, or maybe not tight enough, wobbled until it broke out?

I figured out what happened guys. I had a collasped lifter on the #6 cylinder exhaust side. What happened was when i traveled home the beretta is pulling 3000 rpm to keep up with the flow of traffic,( city highway traffic) And when i let off the throttle to get off my exit i heard a couple backfires, then when i got to stop sign at the end of the exit I heard a loud ticking noise. What happen was both the intake and the exhaust valves were closed when one of them was to be open and built up too much pressure and blown the plug loose, i drove the car home, approx 2 miles, when i pulled in the drivway thats when the plug was blown complety out of the head. and it took the threads out with it. It really did some damage to the plug port. I'm going to put a junkyard engine in it just cause its cheaper than getting new parts to repair the one thats in there now.