I can't imagine loctite would totally insulate things, I know it's an insulator but there would still be plenty of metal on metal contact. Blue is good for 300 degrees red 450. But I'd probably go with some plugs that didn't have the screw on end if that's the case.

I've not have any issues like that on any of my bikes or scooters, but then again none have had an engine as big as on the Morgan, and I don't know that I ever ran plugs with a screw on nipple.