What is the best process for painting a cast iron block ,I have a new block with light surface rust.

Also if I use aluminum heads should they be painted they are the dart ones with the special coating.

I never had luck with the spray on engine paint. Has anyone tried Por 15?

we always use a light etching primer and then just use the duplicolor GOOD engine paint not the cheap 3 or 4 dollar a can stuff the 6-8 dollar a can engine enamel and never have any problems. sometimes we use the duplicolor engine enamel clear over the paint depending on situation and it seems pretty tough.

I like Deltron for single stage engine paint. Clean it thoroughly and wire brush it if need be then apply a good epoxy primer like PPG's DPLF then shot on the single stage. Durable as all heck and easy to clean.

Stupid question here, but am I correct in assuming the engine is out of the boat? If so, take it to a reputable machine shop and have them runt he block through a boiler/washer. Afterwards, the machinist will take grinding pads to any rust (no it won't damage the block). I'd recommend putting the block back together as a long block, plugging all holes, and using the GOOD duplicolor or engine enamel mentioned by Gh700xx. It's probably be easier to paint it with cheap valve covers on and then paint the covers you plan to use separately or throw some chrome stuff up top.

I do this on all engines I build and, most recently, a 23 T-bucket replica that I built. It's been 3 years and counting with not so much as a chip of paint even with some oil clogging up my evacuation tubes making a mess on the block. Personally, I like black paint and have found it keeps the engine cooler by a few degrees, but the temp difference isn't really noticeable if you are going for looks over balls to the walls performance.

Also, if you do go with the spray can engine enamel, don't use any of that fancy crap (ex. mirrored finish for whatever color) that says it will with stand a nuclear meltdown kind of heat. That over priced crap will end up in your bilge and have you slamming your head repeatedly on the engine cover for using it.

that is true forgot to mention that barnacle

Thanks to all for the advice

Glass Dave ? Any Idea how hot the Deltron can get before it loses Its bond. I Did not think about using it on an engine, I am sure a black car in the sun gets pretty hot in Arizona! I think this is the way I will go unless I hear otherwise.

I have tried all the spray engine paints and never had good luck.

The spray cans require some really good prep work. I've never used the Deltron, but am looking into it. If it's like the ceramic header paint and claims it can withstand 1200 degrees I'd be skeptical.

Deltron is ppg "fleet" paint. Absolutely zero in common with "rattle can" quality paint.

How much is deltron? If it's like $100 for paint IMO that's nutz.... And to do it right you need to buy primer too.