Do you use Primer on your engine before you paint it?

-
myasylum

myasylum

Well-Known Member
Joined
Sep 18, 2008
Messages
1,740
Reaction score
4
Location
Las Vegas, NV
Should I use a High heat primer on the block first or does that not matter for the engine.

Also if you do use a primer, should you then use primer on the headers first as well??

Thanks!
 
I didn't use primer when I painted my 318 Hemi Orange.
Just went to the local Napa and bought myself some Rust-O-Leum 1200 Degree High Heat Spray Paint in "Chrysler/Chevy Orange".
I wiped the block all down with mineral spirits after cleaning any grease off of it and just sprayed away.
Worked great, haven't had any issues with the paint, still looks brand new.

However, I didn't paint my manifolds, so I don't know how it would have held up on them.
In retrospect, I should have, but my friend insisted it wouldn't look good, but frankly, rusty manifolds don't look any better...
 
yes use high heat primer and make sure your block is spotless and use first clean on it before. Follow the instructions for the paint and use clear and the paint will adhere very nicely.
 
Whats this High temp Ceramic paint that they have now?? Is that a better paint? Or is that just more of a marketing gimmick?

And what about this "etched" primer? Whats that all about?

They have a high temp clear?
 
What about temp paint?

500 for block
1200 for headers?

What is suggested?

Thanks!
 
I haven't had too much luck finding a header paint that will last longer than a few hundred miles. Even the 1200 degree stuff. Best bet would be to get them ceramic coated or let them rust.
 
whatever you use make sure the block is extremely clean before you lay paint on. When you think you got it as good as possible. Do it again two more times, then spray:cheers:
 
i'd use high temp. primer and paint on both your block and headers, it will just prolong the life of the paint and help the headrers from rotting out.
 
I just use plain ol' Rustoleum bright red for the block (it appears to be the same shade as '67 273 red) with Rustoleum brown primer first. I don't think the block gets hot enough to need header paint on it.

As far as headers go, I've tried all the "high heat" rattle can stuff, and it never lasts. I mentioned it (that header paint sucks) to a guy who does powdercoating and stuff and he said that if you look closely at the directions, they state that you need to bake it (or start the engine) about 20 minutes after applying the header paint.

Ha!.....good luck, I could never install the headers that fast and I don't have an oven that big at my house. Anyway.....that's what the directions said on the header paint I was using. I ended up just nickel plating my headers for $50.
 
A stupid question, couldn´t too thick of paint layers on the engineblock get the engine to overheat or keep a higher temp?
 
I'd say minimal, if at all. The water jacketing is doing all the heavy lifting in that dep't. I'll bet if you wrapped the whole engine in fiberglass insulation, you might see a change, but I doubt it.

I did wonder the same thing, when I go to the junkyard and see all those engines with one inch of crud all over them......it does make you wonder.
 
Over on Moparts, some guys are useing BQ paint for the headers, & surprizeingly enough, its holding up from what they say.

I would use primer on the block before painting, i'm going to do that this time around, primer not only seals, but it tends to hold on to metal better then paint, & paint really holds on to primer well.
 
I have painted dozens of blocks and I have never used primer on them.....I get the 500 degree duplicolor engine paint....just make sure your block is clean, wire brush the hole thing and then brake clean it all so there is no oil residue and then spray it right down with the engine paint. its all about personal preferance. I have seen guys go as fasr and angle grinding casting marks and primering and blockinging and primering and blocking and putting it in a booth and painting auto paint and painting it to look like glass when done. All comes down to what you want to see it look like and what you want to spend and how much work you want to put into it
 
I use por-15 manifold paint. never tried it on headers, but seems to work well on manifolds
 
Whatever you do.

Make sure you atleast get 1200 degree paint for your headers or it will just burn off (brown and flake then rust) and NEVER clear them lol...seen guys do it and it always turns headers brown.

Good luck
 
I've done it both ways. Without primer is probably OK, but I think I get better results with primer. Enough better to justify the extra hassle? Who knows.

I use Rustoleum red oxide primer. I typically brush the one coat on the castings and spray one coat on the tins before assembly (I prime the inside of the block casting as well). Then after the engine is assembled, I thoroughly degrease and spray a second coat. Finally I spray a couple coats of color. I keep some old valve covers around as masking shields if I'm gonna put fancy ones on, and unpainted intakes look totally gay to me so I really don't mask much off besides the ports.
 
Well, some one ask for pics so... here they are.
First of all, I'm not a very good painter, second... I've never done this before.
One thing I did find out is what "thin coats" really were. I had some issues I had to fix, not really understanding what "thin" was. I now understand that THIN means THIN!
It's under 60 degrees here now too already so that don't help much either, so I'll just be letting it sit for awhile.
As you see I did use 500 degree primer. We'll see what happens with that.
It didn't seem, at first that the paint wanted to adhere to the primer. That's where the "thin coats" came in real handy and I painted a few layers.
I have to areas to touch up I know. I left the oil pan black. Don't ask me why? I don't think it will look bad. Kind of Halloween looking :)

here it is...

7.JPG


10.JPG


12.JPG
 
C130 Chief said:
I've done it both ways. Without primer is probably OK, but I think I get better results with primer. Enough better to justify the extra hassle? Who knows.

I use Rustoleum red oxide primer. I typically brush the one coat on the castings and spray one coat on the tins before assembly (I prime the inside of the block casting as well). Then after the engine is assembled, I thoroughly degrease and spray a second coat. Finally I spray a couple coats of color. I keep some old valve covers around as masking shields if I'm gonna put fancy ones on, and unpainted intakes look totally gay to me so I really don't mask much off besides the ports.
Click to expand...


YOU PAINT THE INSIDE OF YOUR BLOCK?????????????
 
myasylum said:
Well, some one ask for pics so... here they are.
First of all, I'm not a very good painter, second... I've never done this before.
One thing I did find out is what "thin coats" really were. I had some issues I had to fix, not really understanding what "thin" was. I now understand that THIN means THIN!
It's under 60 degrees here now too already so that don't help much either, so I'll just be letting it sit for awhile.
As you see I did use 500 degree primer. We'll see what happens with that.
It didn't seem, at first that the paint wanted to adhere to the primer. That's where the "thin coats" came in real handy and I painted a few layers.
I have to areas to touch up I know. I left the oil pan black. Don't ask me why? I don't think it will look bad. Kind of Halloween looking :)

here it is...
Click to expand...

It does not look too bad.

as in thin coats.....I guess i would call them dust coats...good way to start a base for the paint to stick to,you just walk around a good foot away from the blockwhile you are spraying until you get a complete even looking "dust" coat. the hole block should be grey but not so thick that you cant still see the block

I then go through with a "thin" coat,about 6 inchs away from the block with even pass's and until you have uniform solid grey color. let that dry and then do the same thing one more time as a final coat.
Then repeat the process with your color.

It will dry in 60 degrees but it will stay "tacky" a bit longer but you should still be fine....its just more ideal in warmer temps.

Looks like from your pictures that your primer laid a "little" thick in spots,mostly on the right side of the block and on the water pump and in the freeze plugs.
I usually ad a couple spurts extra on my freeze plug for added rust protection anyhow.

As for color,not sure if its just the pictures but looks like you may need to run one more coat of color...almost loks transparent in certain areas like it could use another coat.

Otherwise, I think your on the right track and I think you will figure it all out.

I have learned that spray painting is a good skill to learn early on in life and have under your belt of skills of trade lol.
 
Outsider said:
That suprises you?
Click to expand...


Yes lol....it does, I have seen guy's paint the insides of there blocks and through use and temperature changes and oil being exposed to the paint.....its no good.

Even more so if your engine has blow by and the oil gets even a little bit gassy smelling,before long your just asking for it to break the paint down and then where does it go?

plugs your lifters and pushrods and sucks to the bottom of your oil pump pick up screen and then no oil gets to your engine and then you dust an engine over a couple dollars worth of paint on the inside of your block.

I have personally seen it happen and will not do it lol.

If anything I would have the inside of the block professionally Teflon coated if you are worried about the inside of your block.

But paint? your asking for trouble,not to mention.....who cares what color the inside of there engine is lol? your never going to see it.

Somewhere I have and engine building guide that explains why not to get paint in the engine and what causes it to break down and also mentions certain chemicals that expel from the paint due to heat and oil and fuel contamination which can inturn break down the viscosity of the oil.

I don't know, I just know I do not paint the inside of my engines but to each his own i suppose.
 
Nice job!

Those are the heads not the block. That little bit of over spray isn't going to harm anything. Don't worry about it myasylum.
 
mullinax95 said:
Nice job!

Those are the heads not the block. That little bit of over spray isn't going to harm anything. Don't worry about it myasylum.
Click to expand...


Some one else had commented about painting the inside of the block....thats what I was refering to.

As mullinax has mentioned though...a little over spray will not hurt anything.

What I am saying you should not do is to actually do a paint job of the inside of the block or the inside of the heads.

Sorry if I made it sound asthough a little overspray would cause total engine failure lol,that is not what i meant.
 
One coat of rustoleum primer on the inside of the block. Never had a problem. Helps seal the casting and aids drainback a little. First engine I did this to was an IH 345 in like 1988. Still runs like new last I heard.
 
You must log in or register to reply here.
-

Back
Top