Paint flakes off engine

[79wagonator]

That sucks The old paint must have been crappy.
Whatever you used to degrease might have also softened the old paint too.
Try brake cleaner to clean it up. Lots of it.
That's what I used to prep before painting
Maybe it will melt off the old paint. Try a little spot 1st.
It also leaves no residue behind.
Just be careful what else you get it on.
I guess you already repainted though
There might have also been some oils on the machined surfaces still, brake cleaner solves that. 8)

 

[mikester]

Hate to say it but to me it sounds like it wasnt prepped right. Is the motor on a stand ? If it is, take a wire wheel (the cup style that looks like rope and goes on a hand held grinder) and take every spec of paint off. Then take a white rag with lacquer thinner and wipe it down. If the white rag is dirty, theres still oil on the block. The paint wont stick to it. No way. It might take a while but it will come off. I probably used a gallon of thinner prepping a bare block and set of heads for paint. I would rather spend the $16 for the thinner and spend the time doing it than to be pissed later on that the paints peeling because I took a shortcut. I use PPG DP50 epoxy primer and Delstar acrylic enamel for motor paint. I hate using rattle can engine paint because its so thinned out you have to put on multiple coats to get good coverage. To me it looks too thick. Plus you have so many more options as far as color.

 

[jacobdavis1979]

ive never used rust converter or primer on a engine block so my gut tells me that might be your problem. On an old motor not a crate i always used a wire brush to get off the thick stuff then brake cleaner and a rag then wax and grease remover. Then just sprayed down 6 thin coats of engine enamel then when dry went over lightly with a hair dryer. Built at least 9 motors and have yet to see one flake or rust. Even re built one of em and paint was still nice enough we cleaned it with glass cleaner. Ive just never liked rust treatment lol.

 

[MUELLERBU]

My experience do not mix any Plastikote product with any Duplicolor product stay with one product, I was painting some valve colors chevy orange with plastikote paint when I ran out of paint, my buddy ran to the store & bought some duplicolor chevy orange, sprayed it on & the paint was crinkling within 10 minutes, (Kind of a blessing cause the idiot bought Hemi orange instead)