Primer on engine ?

[JEFF CLAPP]

Would it be advisable to use primer on the engine? I use JD Buff Yellow primer sealer on most all the other parts. What does everyone else do ?

 

[mgonitzke]

I prime anything that gets painted unless the paint instructions state not to. It will burn off the exhaust port unless you use high temp paint.

 

[mgwin]

Go lightly on the primer and paint for the engine. Those cooling fins need to be able to dissipate the heat. I personally do not paint the head either.

 

[JEFF CLAPP]

Yes sir. I probably want paint the head either. Thank you for the advice.

 

[Doug Rusk]

Wouldn't scare me to paint the head but I would use engine paint and try not to coat it too heavy. As said already due to cooling concerns I probably wouldn't not prime anything other than the time work around the motor, if that. It probably wasn't primered originally

 

[mgonitzke]

Aluminum head should be left bare. I would still paint the cooling fins on the block though...a thin layer of high temp paint will have better heat transfer properties than the layer of rust that will form if it is left unpainted.

 

[jdrong]

Well, possibly, here we go again with the paint on cooling fins discussion. It's not solvable, too much information, not enough actual knowledge. For every theory against painting fins there will be a theory that says the opposite. I will agree that putting on enough paint to clog fins will cause overheating so there are the extreme conditions that will make a noticeable difference. In this case Google is the enemy, too much info from people that are only repeating what they read and have no actual experience.

 

[JEFF CLAPP]

Well, possibly, here we go again with the paint on cooling fins discussion. It's not solvable, too much information, not enough actual knowledge. For every theory against painting fins there will be a theory that says the opposite. I will agree that putting on enough paint to clog fins will cause overheating so there are the extreme conditions that will make a noticeable difference. In this case Google is the enemy, too much info from people that are only repeating what they read and have no actual experience.

Point taken. So far, no primer on the engine block , prime only the engine sheetmetal with high temp primer , and possibly will be ok using Ironguard paint with hardner ??

 

[mgwin]

Not sure about cast iron, but no primer on regular metal will cause the paint to flake off easily later on. At least that is what I have seen.
I have also seen paint flake off of primer, because the primer was not properly prepped before painting.
As Matt stated, the engine will rust if not treated with something. Cast iron loves to rust.

 

[jdrong]

Primer sticks to metal better than paint does. Paint sticks to primer better than it does to bare metal even if it is the so called direct to metal type of paint. A light coat of primer on all bare metal will always help with paint adhesion. Catalyst or hardener will usually help paint to cure faster, be tougher and more able to stand up to spills and the elements. Aluminum takes extra prep for good paint adhesion but the head is mostly covered by sheet metal and will not rust so I wouldn't worry about painting it. If you're worried about cast iron rusting, a light coat of primer, finish assembling the engine and top coat the assembly. One more thing, if primer sealer is allowed to sit for more than a specified amount of time (usually 24 hours) it should be scoffed off. 3M Scotchbrite pad or the equivalent will suffice. Primer surfacer should always be sanded. It's always best to follow instructions on the can no matter what anyone tells you.

 

[JEFF CLAPP]

My only concern at this point is if the primer sealer i am using will be resistant to heat enough to stay on. Has anyone used the JD Buff Primer Sealer on a small engine ? I have seen replacement engine blocks and other assemblies in the JD primer sealer when i worked for a JOHN DEERE dealership. The yellow color should cover easily under the Ironguard yellow.

 

[jdrong]

My only concern at this point is if the primer sealer i am using will be resistant to heat enough to stay on. Has anyone used the JD Buff Primer Sealer on a small engine ? I have seen replacement engine blocks and other assemblies in the JD primer sealer when i worked for a JOHN DEERE dealership. The yellow color should cover easily under the Ironguard yellow.

My experience with heat resistant paint is that it is mostly a scam. I've used everything from automotive paint to spray cans on engines of all kinds, they all hold as well as the so-called heat resistant, well maybe not the cheapest of cheap paints though. If the metal is clean and preferably roughed up a bit, the paint will either bake on or burn off in the same places. This is just my personal experience. I don't think I have ever used JD Primer Sealer so I don't have direct experience with that.

 

[jlord]

What about the paint they sell for brake calipers in the auto-parts stores? It seems that if it will take the heat of brake calipers, it might just work for engines.

If that doesn't work, then how about wood stove black/polish ? That I'll take up to 850 degrees or so.

 

[jdrong]

I used the cheap black spray can Rustoleum on my new calipers years ago, still there. I don't believe calipers get much hotter than engines unless you're racing. As far as my experiences go, hi-temp, vht paint, etc., when used on exhaust parts will all do the same, whatever is used to carry the pigments (resins or whatever) will always burn away quickly leaving only the paint pigment. Most pigments will burn away quickly too, the exceptions may be black, white, or aluminum. You are then left with a powdery pigment that has no ability to prevent rust and will sooner rather than later wash, wear or blow away. This pertains to headers, exhaust manifolds or ports near the exhaust, even CC mufflers. I read that graphite paint worked well on exhaust manifolds. I thought I would try it when I had the exhaust manifolds off of my 350 V8 street rod. They looked like brand-new manifolds but as I expected, lots of smoke when the engine was first started and burned away the resins. I assume what was left was just the graphite which looked good longer than I thought it would.

 

[jlord]

I used the cheap black spray can Rustoleum on my new calipers years ago, still there. I don't believe calipers get much hotter than engines unless you're racing. As far as my experiences go, hi-temp, vht paint, etc., when used on exhaust parts will all do the same, whatever is used to carry the pigments (resins or whatever) will always burn away quickly leaving only the paint pigment. Most pigments will burn away quickly too, the exceptions may be black, white, or aluminum. You are then left with a powdery pigment that has no ability to prevent rust and will sooner rather than later wash, wear or blow away. This pertains to headers, exhaust manifolds or ports near the exhaust, even CC mufflers. I read that graphite paint worked well on exhaust manifolds. I thought I would try it when I had the exhaust manifolds off of my 350 V8 street rod. They looked like brand-new manifolds but as I expected, lots of smoke when the engine was first started and burned away the resins. I assume what was left was just the graphite which looked good longer than I thought it would.

I've got headers on my truck. As soon as I bought them I got them "ceramic coated" by Jet-Hot company with Jet-Hot’s Ultra. Good for up to 2500 degrees F. If it's good enough for NASCAR and John Force, it's good enough for me.
If the price is too high, you can get a decent product off of Eb*y called "Cerakote C series". It's an air dry product, so you don't need a high temp oven to cure it.

 

[jdrong]

I've got headers on my truck. As soon as I bought them I got them "ceramic coated" by Jet-Hot company with Jet-Hot’s Ultra. Good for up to 2500 degrees F. If it's good enough for NASCAR and John Force, it's good enough for me.
If the price is too high, you can get a decent product off of Eb*y called "Cerakote C series". It's an air dry product, so you don't need a high temp oven to cure it.

I wouldn't think that ceramic coating is paint and not feasible for use on CCs. I also wouldn't think anyone would try to ceramic coat their Kohler engine or exhaust pipe, muffler but.... you just never know.

 

[JEFF CLAPP]

I also agree. I'm not interested in ceramic coating anything on this cub. I certainly want a nice tractor when done but something I can drive and use if needed. I might take it to local fairs or tractor shows but I not building a museum piece. What was good enough for IH is good enough for me.