: "Finally, I stripped, sanded, and painted the pulleys and brackets using the DHT enamel primer and DHT semi-gloss enamel engine paint. These came out OK, not great (and I re-did twice). Not sure why, but the paint was reacting and kept wrinkling."
: Welcome to the world of EPA reformulated spray bomb paints. I created a thread on just this subject. Very frustrating trying to get a smooth good finish if you spray the paint like we used to. Yep, looks great, nice and glossy/shiny so you go and spray another top coat, or even clear to get some depth, and you watch the paint "crinkle" and "craze" on you once nice part. Sanding it down to get rid of the defect and respraying only brings the poor qualities back, or worse, adds a few more of the imperfections you were just trying to get out! LOL
Here is what I learned. Spray your paint, let it stand about 5 minutes to dry slightly, and then hit it with another coat - being careful not to overload the paint so you get runs, but not too little that you get a dry spray look either. If you want to clear it, wait another 5 minutes and hit it with clear.
It used to be you would wait about 20-30 minutes for the paint to dry a little and then re-spray -this does not work with these paints. And if you think the primer should help, it doesn't. Tried several different types. What I found best is the metal etching spray bomb primer. It is a green in color when sprayed. It will dull out to more of a flat green when it gets near to being dried out - doesn't take too long. When you see the change, hit it with your color coats as above.
The other way is to spray your color and then let it sit for about 2 weeks so that ALL the slow drying solvents evaporate and the paint hardens. Then you can put another cover coat or clear on, but again, not too heavy or guess what?
I found spray bombing my brackets & pulleys very frustrating and had to fight with them to get a good finish. I finally accepted that a few were going to have to be OK with the minor blemishes and I don't suspect too many people will see them anyway - its just that I know about them. LOL
The other option is purchasing paint from the local autobody/paint supplier and spray painting with a spray gun. I have all the equipment to do this, but didn't care to go through all that just for brackets & pulleys as mine is not a show car and spray bomb was cheaper and more convenient.