Sorry, you're not very clear on your comment, are you saying the SPARK-PLUG actually blew out of the cylinder head ?? or something different .. if it was the plug, I'm sure you must have more of a problem, like maybe the plug was installed with a Heli-Coil and it stripped out, or improperly installed ?? and you put it back in HOW ?? screwing it in, or just plopping it in the hole ?? makes no sense to ME ..?????
EDIT: this could have been the white smoke problem from the very "git-go"