Scotch bright pad on heads and mating surface's
 

i know its ok to use green scotch bright pads (by hand only) and wd-40 to remove the old gasket material from the deck and cylinder head mating surface. my question is... how much can you take off of aluminum with a green scotch bright pad? would it be ok if you had a tiny scratch (can barely feel it with a finger nail) on a mating surface and you used green scotch bright pad to "smooth" it out so you really couldn't feel it with your finger nail?

don't bash me if you think its a dumb question.

if im correct on my knowledge (which is iffy lol) it depends alot on gaskets and blind luck. ive put together a couple of shady sealing surfaces and got lucky but that was with the paper style felpro gaskets. now gm mls gaskets if im thinkin right need a really smooth sealing surface but i heard a rule of thumb if you cant hook it with your finger nail you should be ok.. now thats what i think it is and someone else can chime in and confirm or deny this for me that would be good cuz id hate to give out bad information and ruin somethin for someone

I used that method to clean up the block, and polish out some light scratches.
No problems after a the first few 100 miles....
Used stock GM head gaskets.

http://inlinethumb10.webshots.com/48...500x500Q85.jpg

I did the same and have done so for years on alum heads and blocks.
Takes forever though!
I also very carefully use a razor blade window scraper. Dull ones.

3M makes roloc disks that are some type of plastic/rubber with little fingers that make this job ALOT easier!!! There are three colors...green is most aggressive i would use it, but the yellow (medium) and white (fine) are what i used and the made it alot easier than doing it by hand with a scotch pad, althought the guy who posted the pic did an awesome job on his block...i used the gm mls gaskets and have had to problems...i also used a straight edge everywhere just to make sure i was true on the deck

If surface prep/condition is in question, use a Fel-pro MLS gasket as they are design for this exact thing.

yeah i did go with the Fel-Pro MLS gaskets, they sealed up nicely. i was just checking to make sure im not the only one who does this when building a motor. obviously if i felt it was to deep of a scratch then off to the machine shop it would go but for dumb shit like accidentally very lightly scratching the mating surface on a "reconditioned" part :bang: then green scotch bright it is :judge: