I noticed that after 30k miles old plugs will round out and the gap widen compare to new, and the surface is more porous and rough.
So if you cut a slot in the middle to create a sharp edge (like the NGK V power) and regap it, can you keep using the same plugs forever?
What else other than the tip wears out?
So if you cut a slot in the middle to create a sharp edge (like the NGK V power) and regap it, can you keep using the same plugs forever?
What else other than the tip wears out?