I`ve been using Duplicolors Engine enamel spray can paints for years, never had any issues with it lifting on staining, even with gasoline, both pump gas and VP leaded race fuel. The black Mercury tall pentroof valve covers that I have had on the past 2 428s and current 427 were painted probably 20 years ago, and still look nice and shiny. I prefer to have sheetmetal engine pieces, like oil pans and valve covers hot tanked to remove any oil residue, which removes any old paint as well, and after a hot water rinse, blow them dry with compressed air. No primer, just the engine enamel, always worked and looked great. You will have trouble if the parts or paint is too cold.