Originally Posted by rbm
Can you reveal the secret of you "patented cleaning method"? I see you painted right over the existing finish on the cam cover and crankshaft cover. Did you use rattle can finish or spray gun to do the work? Also, did you prime before the topcoat?
Sorry I missed this post.
Cleaning the cases I use brass wire brushes of various sizes and shapes in a hand drill. Set the speed quite low to avoid damaging the aluminium surface (brass wire brushes are less aggressive than steel).
I use some light oil as a lubricant on the surface (WD40 is ideal). Then more WD40 to clean and lift the dirt that the brushes remove.
Finish off with a good thorough wash with detergent. Oil is the enemy of the casings as it allows the dirt to stick and get ground in. Lastly I use a quality polish just as I would on a painted surface for protection.
When it came to the crank and cam covers, I cleaned and polished the ribs and the BMW logo before masking. The paint then went on over the masking tape.
No primer. I just keyed the old finish and then used aerosol cans of satin black enamel.