ive seen it many times were a block gets painted then soon after the paint flakes off. whats the best way or your secret to painting a block?

 

Probably because there's still a film of oil (including oils from soaps) still on the block. I've found that paint sticks best to metal if you use some fine sandpaper on it first (high grit like 1000) to kindof "etch" it to help the paint stick better. If you do this, make sure you wash it again to get the sandpaper grit off first.

 

Soda blast the block, I would stay away from sandblasting. Soda blaster is water soluble. Or wire wheel and sand paper as well.

 

i had the white crusty looking corrosion on my block. i ended up using a product called "AlumaBrite" or something like that to remove the corrosion. it's an aluminum safe acid wash used for shinning up sail boats. followed that with soap and water, let it dry in the sun and hit it with 8-10 light coats with a bit of dwell time in between.

the motor hasn't been reassembled (or run) so it hasn't heat cycled yet, but my expectations are high.

 

I used a bunch of brake clean and different types of brushes to get into all the spots. Then used some etching primer and then my paint. It's been in the car and ran and I've had no issues. I have other friends who did the same thing with great results.

 

I agree with sc34dc4. I too did the brake clean and brushes/red scotchbrite and used the etching primer and paint. It has never flaked off or nothing! Its also pretty cheap to do...

 

Brake clean, a red skuff pad. Use blow gun to blow of debris, use a wax and grease remover. Apply a primer sealer for better adhesion vs without and the the final color coating.