engine paint

I know this is going to sound like a stupid question but here goes....about 10 years ago I had my 383 out of my Coronet and cleaned it up with engine degreaser and painted it Hemi Orange out of a spray can (High Temp Engine Paint) Shortly after that the paint peeled...a couple of years later I detailed the engine bay, removed the motor, cleaned and wire brushed it down and sprayed it again...fast foward to now..it's peeling again...in both cases High Temp Engine paint was used....help...

I had the same problem with so-called "Engine Enamel" (but only once). Won't be using that crap again!

I too would be interested in hearing from those whose engine paint DID stay attached to the block...

Did you degrease it?

I just use whatever enamel paint is at Home Depot in a color I like, I follow the directions and it lasts. Painted the 318 in my Diplomat apple green 20 years ago, still there, no peeling. But I don't have a resto car either so the correct color doesn't matter to me.

Never had a peeling problem, and the 1st engine I painted was in the early '70s. Oldest one I have is still fine 33 years later.
That's rattle-can engine paint, rattle-can "industrial" paint (race cars, non-OEM greys), or Bill Hirsch paint from a gun.
It's critical to start with a clean, grease-free surface.
I always use a primer with some zinc content, though others here don't prime at all.
I scuff the tin with a red Scotchbrite pad after cleaning & before priming.

Ironically, the worst "luck" I've had is with powder-coated wheels; I'll never do that again.

I suspect it may not be the paint but rather the surface preparation. After cleaning and before painting, the surface should be prepped with a suitable wax and grease remover. Some brake cleaners will work as will acetone followed up with an alcohol rinse. Your local paint supplier may be able to help as well.

I can't speak for the OP, but I definitely used Grease & Wax Remover then a rinse/wipe (think it was brake cleaner).
Yes, surface prep is usually the most common cause of paint failure, but I knew that and followed directions
I suspect the machine shop sprayed some kind of gray coating or paint on the block to keep it from rusting. Where the paint has come off in big sheets, there is hardly a trace of rust underneath. Maybe I should have sanded first!

It may have been exposed to some sort of contaminant like silicone ( think lubricant overspray) and that can be a real problem to get rid of, especially on a porous surface. Sanding typically would only spread it around. The only other thing I can think of would be to use a metal etch solution.

I use paint from www.hirschauto.com and have never had a problem. I have even brushed it on with no brush marks.

thanks to everyone for their input on my problem...I did use an engine degreaser and wire brush and cleaned the block as best I could....I'm going to do this again but this time I'll try using the brake cleaner and wire brush...while I agree that the problem might be the prep, I did do prep work last time...maybe the third time will be the charmer..thanks again to everyone for your input...I might look into a high temp primer..

Maybe consider finishing of the cleaning using body shop quality lacquer thinner and wiping real well with clean rags before you paint, also an epoxy primer or some good quality etch primer.

I agree, I have used their paint from a rattle can and a quart, always a good result. High solids, dries fast, forgiving of my mistakes. I have it on two engines.

I use to wipe the block with acetone, then wipe with muritic acid and then a dulted baking soda water wipe to neutralize the acid followed by clean water. One more wipe with acetone.

Get the block very warm to the touch and lay on light layers of color. I had a old electric wall oven that I built a sheetrocked and R19 insulated paint oven that was 4 foot cubed inside for baking parts. Set it to 150F for 1/2 hour.

All these new paint formulas are crap without the lead and other dangerous chemicals.

Hirsh paint is the best..flows nice...
https://youtu.be/NI5rdp0R15o

The wire brush will likely absorb and spread any remaining contaminants into the pores of the cast iron. With the problems you have had I would strongly encourage getting a metal etch solution from the local auto paint store. Then etch prime,and paint away. Good luck

After cleaning I use laquar thinner wipe it down and use etching primer. Never had a problem. Next one I do is gonna be powder coated although I know that peels after a few years I like it. I'm hoping the new stuff is better.