New to me A4

[nyvoyager]

I have an engine sitting on a pallet in the yard, fired up, test run and ready to go in.
I still need to clean it up and think I would like to paint it.
can anyone provide a procedure that they have had success with?
I'd greatly appreciate.
When I painted my last engine it all seemed to rust faster and I'd like not to repeat that experience.

[Al Schober]

Simple question - answer isn't so simple. As perhaps you suspect from your last engine paint job.
What's on the engine now? How is it holding up? Suspect the answers are 'don't know' and 'OK'.
Paint is usually applied in two layers. The primer is first layer (sometimes two coats) which bonds to the base and provides a 'tooth' for the finish layer. The finish layer gives you the color/gloss you want and protects the primer from the elements.
Unless you're going to remove the present paint, the present coating is your base - not bare metal. ANY coating you apply will adhere no better than the present paint. Going to a hi-tech primer (2 part epoxy) doesn't make sense unless you're going down to bare metal (or at least clean solid rust).
OK, top coat. How protective? Top of the line is probably 2-part urethane for high gloss and durability. The stuff can kill you if you don't use proper protection (outside air supply, etc). No experience with 2-part epoxy top coats. I'm going to purposely avoid any comparison between alkyd (or urethane) enamels and latex paints.
Let's stick with 1-part paints. Spray or brush? Do you want to spend your time masking or painting? Engine on a pallet? - there's not much to mask. I'd go spray - rattle can or spray gun? If you don't already have a compressor, go rattle can. Rustoleum is a good brand.
Hope this helps.

[nyvoyager]

Thanks Al
It is the original A4 paint
It is not likely I will strip to bare casting
I will re-read the options you presented and probably have additional questions