I painted my iron BBC engine block with DPLF followed by PPG DBC base and PPG clear. I've read that automotive urethane is fine to use on engines so that's what I used.
However, I now need to paint my valve covers and intake manifolds which are aluminum. I don't think I can use the same process because aluminum requires different preparation and primers. They are clean, new, and have never been used on a running engine.
Has anyone here tried this, and what did you use? I did an internet search on the subject and some people recommend zinc chromate primer, some recommend etch primers, and there are a lot of other opinions. I want to topcoat with the same PPG base and clearcoat.