Hot Stuff

I've got a set of thick aluminum MT valve covers on my 79 L-82. Been on it for years and were looking pretty shabby so I pulled them off cleaned them up, sanded them to get a better paint bond and painted them with a good high temp black paint. I didn't prime them. I seem to remember that the paint was supposed to be self priming.When I put them back on the paint and fired it up cracked real bad and now it really looks shabby. Can anyone give me some good advice on painting them that's going to hold and look respectable?

Capt. Shark

I painted my L82 finned covers and they turned out pretty good. Cleaned and sanded and then used self etching primer under hi-temp motor paint and then clear coat. Baked them in the oven, also. No, she wasn't home
That was last year and they have held up well, maybe the self etching primer is the key.

maj75

Sanding isn’t always enough to get good adhesion with paint. Old valve covers tend to get oil on them and this soaks into the porous aluminum. Sanding often just spreads oil contamination. When you paint the covers and they get hot, the oil is released and the paint comes off. Take them to a machine shop that has the hot cleaning machine that they use for blocks. The heat and steam do a better job of getting the old oil out of the casting. Bake the valve covers before you paint, wipe down with acetone and let them dry. Then prime and paint.