1995 Mazda B2300 stuck spark plug

I have a spark plug on the passenger side of cylinder #1 that broke off. I managed to get the ceramic out and blow/vacuum out debris that fell into the bore. However the threaded part of the plug is still ceased in the plug hole. I tried various penetrating lubricants, heating it, freezing it, and trying to back it out with a spiral type screw extractor on an impact gun. Due to the value of the truck, it isn’t worth the cost involved in removing the head, would I be able to tap out the hole and re thread it without removing the head, and if so how could I prevent getting shavings into the cylinder bore? Also would it need to be at bottom dead center to do this?

You should have pretty good access to that plug hole on a B2300. I would thing any one with an acetylene torch would be able to heat it enough to get it out. Barring that I would put that hole at top dead center and stuff the combustion chamber with a grease coated rag or rope before drilling and tapping. You can get it out afterward with mini long nosed pliers or a hook made from a coat hanger.

If you try to drill it out and retap the threads…coat the drill bit with a lot of axle grease. Then coat the tap with the same axle grease. This will give the chips from dropping into the cylinder.