When an exhaust stud goes bad on a car, I replace it by drilling it out, tapping it a bit, throwing some tools around, drilling it again, then go to an air motor, have a beer and finally it comes out. When I screw the new stud in I butter it up with Never-Seize to make it easier the next time.
Here's the problem: I've been asked to replace a broken stud on a Pawnee tow plane. It's a 4 cylinder pancake engine with aluminum heads. The studs are steel and there's a helicoil in the head.
Do you Lok-Tite the OD of the helicoil, insert it, then duck butter the stud with never-seize? Never-seize all or it?
Are copper nuts a help or hinderance?
What does the FAA think about this? I'm sure there are rules, I just don't know them yet.
Dan

