Make Engine Paint Stick

[Sharps40]

So, my new engine is 5000 miles down the road. Everything was cleaned and degreased and painted with VHT engine paint.

Carb cleaner removes it.

Oil removes it.

Water removes it.

Raising the hood removes it.

Air rushing by the motor removes it.

Looking at it makes it loose its gloss and then wear off.

The only place it won't come off is the intake manifold....nothing short of an atomic bomb can remove it from there.

So....do engines / tins get primed first? If so what kind of primer?

Or am I living in the misery zone of no paint is ever gonna stick and should just pop for a totally chromed block and tins. (which would look great with the black accents of hoses, belts and perhaps gaskets)

[62 Barnfind]

I was worried about the same problem when I painted my engine. So when I took it out I cleaned, degreased and sanded the whole thing before I painted it. Used Dupli-color engine primer before it was painted. I haven't drove it much just up and down the neighborhood, but it is still holding even on the exhaust manifold. I hope this helps!

[PGSigns]

I just use the duplicolor and it does well. I hit mine with brake clean and then wipe it down with enamel reducer or prepsol, blow it off with air and then let it sit a few hours. The last thing that goes on as a cleaner needs time to fully evaporate off the metal.I also try and heat the engine to above 60 degrees if doing one in the winter and never have an issue. What did you use for cleaner and degreaser? Sounds like it left a thin film on a lot of the metal.
Jimmy

[Sharps40]

It was stripped and degreased with some prepsol. The reman block came with a coat of black, don't know if it was paint or some other type of rust blocker. Pretty much wiped off. I think yer right......porus old iron probably holding onto a lot of oils. Ah well, maybe a chrome valve and side covers and a nice polished aluminum manifold heat shield and let everything underneath peel. As it is its not too bad. 6 months old and looks like a well cared for older motor. Carb cleaner seems to be the best paint stripper under the hood though!

And a basic flaw.....didn't use primer or even see duplicolor engine primer on the shelf. Figures.......engine paint ain't like house paint, no primer mixed in the base color. HA!

Ah well.....chrome it is....cause Chrome Will Getcha Home!

[66farmer]

VHT does have a primer. I used it on my exhaust and it worked good.

[NEWFISHER]

My trick:
Spray bottle of laquer thinner, wire brush. Dry and then spray with bumper chrome rattle bomb, the stuf sticks to anything. Let dry several hours then prime and paint.

[K98AL]

I've painted engine blocks with hardened (two-part) enamel before. Nothing affected that stuff! Painted lots of Harley jugs&heads with Krylon engine paint. It stayed well, too, but surfaces were typically sandblasted first.
Getting the paint to the metal with ZERO oil between is the key.

[Sharps40]

Well heck if if Poormans Chrome sticks to everything I could be blingin by the weekend!!

[ultrahd4me]

I also started with a remaned 250 marine engine that had the black primer. I sanded mine with a 3m 220 grit pad on my 4" grinder, then i used the tractor paint from TSC in Kabota orange. I sanded the block and parts then cleaned them with acetone, followed by 3 coats of paint sprayed with a gun. The engine turned out great. I sold the truck, but I think the paint has held up good on the engine.

[NEWFISHER]

Originally Posted by Sharps40

Well heck if if Poormans Chrome sticks to everything I could be blingin by the weekend!!

I always Paint over it and use it as the foundation on greasy parts, but hey you can run it shiney

[siggyfreud]

Probably just needs more prep than was done. Really need to degrease it will, and then either etch it with acid or really rough it up. The iron is porous and should take paint OKAY, but giving it more material to latch on to never hurts.

[K98AL]

Originally Posted by siggyfreud

Probably just needs more prep than was done. Really need to degrease it will, and then either etch it with acid or really rough it up. The iron is porous and should take paint OKAY, but giving it more material to latch on to never hurts.

There's probably plenty of grease and oil in the pores of that cast iron -
when it heats up, oil starts comin' out, lifting the paint off.

[Apache809]

Glad you started this thread. Good info. Thanks

[Sharps40]

I think I'm gonna let er rust!

[64fleetside]

Nothing beats regular automotive acrylic enamel with hardener for engine paint, you will need a spray gun though.

[theastronaut]

Oven cleaner with stainless bristle brushes to get the gunk off, then use an epoxy primer, and then urethane single stage with hardener. It's worked on my magnesium VW engine block for the last 20k miles so it should do good on cast iron. Magnesium is pretty tough to paint successfully!

[Sharps40]

Originally Posted by theastronaut

Oven cleaner with stainless bristle brushes to get the gunk off, then use an epoxy primer, and then urethane single stage with hardener. It's worked on my magnesium VW engine block for the last 20k miles so it should do good on cast iron. Magnesium is pretty tough to paint successfully!

I'm definatly gonna let it rust....! That's a lotta work. I wonder if plasti dip would stick?

[Rich 5150 69]

Not sure why your having issues with the paint sticking other than the builder what ever they did not do before painting, oils coming out of pores, when I built my last engine ( 400 sm blk ) after got it back from the machine shop I mixed up a batch of tide clothes soap in a 5 gallon bucket hot water, scrubbed inside and out, using hot water to rinse, repeated four times, then got the block as hot as I could get it with water and then blew it dry with compressed air, used simple polyurethane stainless paint brushed it on, still looks good today after ten years. No flaking, peeling..

[Sharps40]

I think when I get ready to change the intake manifold I'll wire wheel off all the paint, clean er up good with oven cleaner and try primer and paint either spray can or brushed on. Then replace the tins with chrome or luminum so they won't be peeling later too.