You can treat that cover with Ospho, available at Ace Hardware or any Big Box hardware store in the paint department.
Wear rubber gloves, apply with a cheap paint brush. It is real runny and will flow into tight spots.
Let it sit overnight. If there is a white powdery residue present, wet a blue paper towel with Ospho and wipe down the cover with it. This will remove the powdery bi-product of the rust conversion chemical process. Since the rust conversion was already completed, no further reaction will occur, and you can wipe down the cover with your favorite degreaser/paint prep product. I like to use acetone for such small parts. Acetone evaporates pretty fast, but with such a small part, it works fine.
I use Rustoleum metal etching primer, followed up with rattle can paint. High heat paint is not necessary for covers, blocks, heads or intake manifolds in my experience.
Last edited by 52Carl; 09/26/2023 12:24 AM.
