help broken valve cover bolt

Ease outs suck juicy dead arctic gay diseased monkey buttholes. All they do is go into the hole and expand the fastener against whatever it's screwed into. Usually breaks the ease out off. Your best bet is to do what Del suggested. Stick a nut on top and build up weld until you weld it to the nut, then back it out. You have to be precise and not weld to the head, just weld the bolt to the nut.

If you can weld a next size down or smaller washer through the hole to the broken stud/bolt then you can weld a nut to the washer. The washer acts as a guide to keep weld off the other surface.