Flathead Engine paint

Hello All, I'm in the process of rebuilding my Stude flathead straight 8. I have the block and head stripped to bare cast iron. Should I prime these parts first and then spray with proper color engine paint? What would be a good primer if it's needed? Thanks for any tips!

No need for primer unless you are grinding and polishing it for a show car finish.

Bill Hirsh has engine paint for everything, flathead Studebaker green, $39 a quart.

http://www.hirschauto.com/ENGINE-ENAMEL/productinfo/EE-QUART/STU%20GREEN/

I agree with Rusty in that thousands of engines have had the "spray bomb rebuild" and turn out just fine for runners, but you've already done the nasty part of the job in getting it stripped to bare metal so why not go the extra mile to help it last longer? Basically primers come in 3 families.... etching primers that go for adhesion only, primer/sealers that help seal against color and moisture movement through the porous primer, and primer surfacers that are used to help level the metal for a smooth high gloss finish. In your case I would suggest a coat of a good quality non-sanding primer/sealer if this is a driver. A few years ago I would have suggested something like PPG's DP-90, but I think that product has been replaced with lead-free versions. I think the last version I saw was called DP-LF (for lead free) but a good chat with your local automotive paint supplier will likely come up with something similar. If you are going for a customized show quality finish (a true restorer would call it over-restoring) and you have ground the block smooth, then I would use a good 2 part high solids primer/surface, and wet sand it with 360 grit before painting. If you are down to spray bombs, try to get the same brand as your paint, or there could be compatibility issues. Generally even though the spray bomb may describe itself as a primer/surface (ok... spell check won't let me call it a surfacer with an R) it will be too thin to have any real levelling qualities, but may enhance the adhesion slightly, and prevent it from rusting longer in a high humidity situation.

I meant that primer is NOT needed. Just use the engine enamel, either brush or spray, your choice. Be sure the engine is free of grease, oil and dirt and the paint will be fine. The factory never primered them.

Now, if you want a perfect "show car" finish you could grind the castings smooth, build up coats of primer and sand smooth but that would actually be less durable than just plain paint. Show car finish will chip and scratch easier and may not stand up well to the engine's heat.

My Stude is my Baby, not a show queen. I'll go with the CLEAN block and the engine color. Sounds like the right thing to do. Thanks guys for your experience!