Donnie,
This is an excellent idea. They also help you trip most traffic lights (signals). You are right about them being strong = so decide where you want them before they are close to filter.
I've used them on the filter and drain plug for 26,000 miles. Using Amsoil for most of that, 6,000 (3k x 2) of that was with Valvoline 4 stroke MC dino oil.
Then about 10k with RotellaT synthetic. I just went back to 20W50 Amsoil.
I've never seen one spec of anything on plug or where the magnets were mounted on filter (i'd cut near magnet on filter shell and peel it back).
I am hoping my engine was perfectly "broken in". These engines ain't made out of 'lumium, is they? (that's aluminum, for you non redneck types).
