Refinishing MAN valve covers

Corrosion on the bolts hast been an issue. A light touch of polish and they look as new.

Same as the chrome.
I learned the hard way that the plating on the inside is an issue when blasting and powder coating. The heat can make the inside bubble. Not good as it could let flakes fall in the engine.

Not an easy answer. You don't want them coated on the inside or the gasket surfaces touched. They blast the outside and leave the insides alone. Then, they cover the gasket surface and the inside with a heat proof tape so none of the powder gets on it. For some reason, a couple of the covers with the hole in them for breathers blistered on the inside. I'm gong to have them touched lightly with a blaster so no chance is taken.
Also, they need to blast as little as possible as the blasting generates heat too.

Hope that helps.

Another trip to the powder coater. Ok, so here's what happened- On the covers with the fill and breather holes some of the blasting went through the hole and that's what caused the bubbles in the back. It's just where the bead blast hit it. The chrome on the back is so thin that it comes off really easy. I just had them touch up the two of them that had the chrome starting to lift on the back as I'm taking no chance with anything going in the engine.

I didn't have them sprayed for a couple of reasons. The prep is much more substantial and it will take multiple coats. Best guess to make them look acceptable was $100 to paint vs $30 to powder coat. Also, the medium wrinkle is really the finish I wanted and it works best with powder coat.

Having a booth is a game changer. It was all I could do to run them through our dishwasher to get contaminants off when my wife was gone .

Like all painting, plating and coating the main thing is the prep. In this case, is the blasting so you don't lose the relief of the MAN lettering but you still have a good surface. It just takes some common sense and time.