Clearcoat on engine

-
4spdragtop

4spdragtop

FABO Gold Member
FABO Gold Member
Joined
Aug 28, 2009
Messages
41,865
Reaction score
25,857
Location
Ontario Parts Unknown
I've read lots about the clearcoat yellowing on an intake manifold. Most I've read is when using it on an intake. Also those intakes always appear either "raw" or painted aluminum. My question, is how does/would it work on the engine when painted oem colors? In my case red. Would the yellowing be noticeable with a red base? Discoloring the heads/block?
I'm finishing up my sb build and I've already put some chips in it just sitting on the stand lol. I used MP oem red paint over top of Duplicolor engine primer.
Thanks
Steve

20240202_094527.jpg
 
Ain't but one way to find out! Looks good for now!
 
I don't think I'd clear it- I was always under the impression that engine enamels needed to go through a number of heat cycles to fully cure and toughen them up; and clearcoating may prevent that ("outgassing" if that applies here?). Maybe I'm mistaken- its not like that's never happened before. :)
I'd just touch up your boo boos with paint and a Q-tip and run it.
 
I have used spray can clear on intakes in the past and it did turn yellow after some run time. It also stained easily when gas gets dripped on it. This last round I used my spray gun to shoot base and clear but have not run it yet to see if there are any issues. The local shop that I purchase my paint from claims this paint will be much more durable and that there should be no yellowing from heat. Hope they are right!

IMG_2138.jpeg
 
I paint my intakes with fuel resistant silver ceramic spray bombs.
Duplicolor and Rustoleum are both good brands, color fast for over 7 years now on several cars.

IMG_2863.jpg
 
Thanks all. I was wondering if the paint needed to go thru heat cycles to fully cure/harden. I clearcoated with Duplicolor engine clearcoat the black bracketry, but nothing directly on the engine/red.
I would hate to clear it on the stand and have all the red get messed up.
@Darter6 is that clearcoated, or paint?
RustyRatRod said:
Ain't but one way to find out! Looks good for now!
Click to expand...

Darter6 said:
I paint my intakes with fuel resistant silver ceramic spray bombs.
Duplicolor and Rustoleum are both good brands, color fast for over 7 years now on several cars.

View attachment 1716200995
Click to expand...
 
Hey Steve...you might find this approach a little different or backward but my Dad taught me to heat the engine surface with a simple propane torch to get quick and more durable adherence to the metal. Obviously this shortens the curing process. The first time I did this would be back in the early 80's. I did a 318 in a 273 red (it was actual high temp engine paint). I sold the engine to a high school friend of mine for a 4 door mopar of some sort. Joe was not at all mechanically inclined so every so often he would come by to have me look at his car. That engine looked good for years and it was driven daily. As for the non yellowing clear...you have to pay up for quality paint. If I do another aluminum intake I might try the Darter6 method! That intake sure looks great. If I don't I will paint the aluminum the same color as the engine. Does the aluminum look good for a while? Hell yes but I am over that. The one you have on the stand looks nice Steve.
 
4spdragtop said:
I've read lots about the clearcoat yellowing on an intake manifold. Most I've read is when using it on an intake. Also those intakes always appear either "raw" or painted aluminum. My question, is how does/would it work on the engine when painted oem colors? In my case red. Would the yellowing be noticeable with a red base? Discoloring the heads/block?
I'm finishing up my sb build and I've already put some chips in it just sitting on the stand lol. I used MP oem red paint over top of Duplicolor engine primer.
Thanks
Steve

View attachment 1716200960
Click to expand...
Looks fine to me Steve. I used the same paint you did and I primed before final coat. Left the primer for two days with garage at about 70 degrees.

No clear.

Duplicolor Hi -Temp red.

Light coats.

Came out great!
 
Thanks Jeff. I have read and seen about using a torch on a block as cast is porous. And if there is another build I may try that approach.
I already had engine mostly assembled(finally) and started the cosmetic side of things. When we did the 273 it was brush-on from Eastwoods and is/was very good. Unfortunately getting that stuff shipped up here is foolish...
jeff alder said:
Hey Steve...you might find this approach a little different or backward but my Dad taught me to heat the engine surface with a simple propane torch to get quick and more durable adherence to the metal. Obviously this shortens the curing process. The first time I did this would be back in the early 80's. I did a 318 in a 273 red (it was actual high temp engine paint). I sold the engine to a high school friend of mine for a 4 door mopar of some sort. Joe was not at all mechanically inclined so every so often he would come by to have me look at his car. That engine looked good for years and it was driven daily. As for the non yellowing clear...you have to pay up for quality paint. If I do another aluminum intake I might try the Darter6 method! That intake sure looks great. If I don't I will paint the aluminum the same color as the engine. Does the aluminum look good for a while? Hell yes but I am over that. The one you have on the stand looks nice Steve.
Click to expand...
 
I too want to protect the visual look of my aluminum heads and intake manifold. I was interested in powder coating them clear, but worried about the finish yellowing.

I believe the best way is to coat the intake with a thermal coating, the heads, not sure. And I know that is costly.
 
Steve, I used Rust-Oleum (high heat) on my Manifold, and it is great! Says 2000 degrees, and gas and oil resistant
 
Ceramic Cast aluminum and no clear. Everything I ever cleared with rattle cans yellowed from heat. I regretted this clear on my engine. I have finished several with just cast aluminum ceramic and they still look great.

Steve 065.JPG


Steve 066.JPG


Steve 096.JPG


Steve 097.JPG


Steve 098.JPG


100_0483.JPG
 
Let’s not forget what a few drops of gasoline does to the clear. The color once heat soaked a few times handles the gasoline pretty good. Clear will turn yellow, peel, check and do all sorts of crazy stuff.
Joe
 
Clear works fine on an engine. Duplicolor and VHT both make high temp clear engine paint. I'm sure that other companies do also. I have used the Duplicolor clear with ceramic (over Duplicolor engine paint, of course), and it worked fine.
 
Powder coat clear yellows really bad. I did a 340 6 pack intake and it sat on a shelf for a couple years and yellowed terrible. I blasted that crap off it. Keep in mind that was just sitting on a shelf, never on an engine.
 
You must log in or register to reply here.
-

Back
Top