Engine Paint...powder coating or just high temp?

[Flinkly]

the engine is in the shop now, and i was wondering what your opinions are on engine paint. i know mine needs some, but with all the fluids that are bound to leak, should i go for a more chemical resistant powder coating or just regular high temp black?

oh, and i'm not particularly interested in keeping it "original" but it will be a satin black on block, head, pan, endplates, and timing cover. the valve cover will be alloy and most everything else will be silver.

when would the best time for painting be? before or after assembly, and what should i tape off? should the whole endplates be painted although alot will be covered?

thanks for all the insight guys.

 

[Brosky]

Re: Engine Paint...powder coating or just high tem

Powder coating requires a baking process that may not be practical for your needs. It can be rather expensive due to the process and masking that will need to be done. With whatever system you choose, parts stripped to bare metal, you have the perfect opportunity to do it right from the start.

POR15 makes a great very durable coating system and I suspect that others may have some ideas as well. The POR15 solution is not cheap, but will last a long time if applied properly. And it can be brushed on for those spots that are hard to spray evenly.

This will get you to the High Temp page and you can check it out from there:

https://www.por15direct.com/s.nl/sc.2/category.235/.f

 

[dklawson]

Re: Engine Paint...powder coating or just high tem

Engine blocks do not need high-temperature paint. The car's cooling system keeps the maximum temperature of the head and block close to 200oF. If you get the block so hot that you damage the paint, you've got more serious problems to worry about.

Regarding POR... people use the term almost exclusively when talking about their "Paint Over Rust" signature product. That isn't really necessary on engines either... but you can use it there as a primer/sealer. POR also makes some excellent enamel paints for engines. I used their A-H Green paint for the block on my Mini. It covers cast iron beautifully with a brush. You can thin it with mineral spirits to spray on surfaces like valve covers that look better sprayed. They offer a lot of OEM colors as well as the black you said you're interested in. The POR enamels are VERY thick with a very high percentage of solids. Great product.

When to paint is up to you. The factory is likely to have painted the engine AFTER assembly. That is certainly the easiest option (both for you and them) as it minimizes the amount of masking.

 

[PeterK]

Re: Engine Paint...powder coating or just high tem

Duplicolor engine paint comes in a wide array of colors and is easy to apply and adheres as well as anything. That's what we use on the engine block and head.

 

[Flinkly]

Re: Engine Paint...powder coating or just high tem

what about problems of paint adhesion with engine oil or brake fluid? i don't see myself getting brake fluid on the engine, but just in case...

is the normal temp of 185 alright for most paints? i figure whatever i have done, it will be engine paint, so i guess someone would have thought of that already.

i'm just questioning since i haven't done it before and want to do it right the first time. /ubbthreads/images/graemlins/rolleyes.gif

 

[Alan_Myers]

Re: Engine Paint...powder coating or just high tem

[ QUOTE ]
Duplicolor engine paint comes in a wide array of colors and is easy to apply and adheres as well as anything. That's what we use on the engine block and head.

[/ QUOTE ]

That's what I use, too. A $5 rattle can of paint is all that's really necessary and can do a super job. Why spend more unless you are doing something really custom (i.e., matching exterior paint color)?

I recently only had to do minor touchup on an engine that I know was last painted completely 25+ years ago with a rattle can of semi-gloss black. The stuff lasts a long time and it was easy to match.

One of the key properties of "engine paint" is resistance to oil and fuel, in addition to moderate temps. Not all coatings are resistant to fuel and oil, even if they are rated "more durable than paint" in other environments.

I'd certainly never use powder coating, largely because of the cost, possible hassles due to the thickness of the coating, having to send it out to a coater, and it's virtually impossible to touch up (which is almost certain to eventually be needed on an engine). Also, unless the more expensive and difficult to apply high temp variety of PC is used, heat right around the exhaust manifold will likely damage it eventually. Most powder coating uses temps in the 400F range for curing. Temps next to the manifold can get that high (but elsewhere on the engine there shouldn't be a problem).

I'd also never use standard POR15 coatings (or similar). I don't know how it would hold up with heat and oil, but my main reason for not using it on an engine is that the finish is simply too difficult to remove. (The same applies to powder coatings.) There are often times during a future repair or rebuild when you want to clean off all coatings and finishes - either the entire block or spot cleaning - to insure proper gasket sealing, etc. Stubborn thick coatings can get in the way or otherwise cause leaks or misalignments. Standard engine paint comes off pretty easily, when you need it to remove it. Powder coating and POR15 require extreme measures to get them off.

I'd suggest painting after the major assembly is done, say just before the manifolds, filter head, valve cover, etc. are installed. Just be sure to degrease everything well, then carefully mask off areas such as the ports, manifold mating surfaces, valve train, etc. I like to paint the front engine cover and sump pan separately, but that's up to you.

/ubbthreads/images/graemlins/cheers.gif

 

[tomshobby]

Re: Engine Paint...powder coating or just high tem

What ever paint or coating, remember that it will most likely be an insulating surface so don't put it on thick.
Unless your engine compartment will be hotter than the inside of your engine. /ubbthreads/images/graemlins/wink.gif

 

[dklawson]

Re: Engine Paint...powder coating or just high tem

I repeat my comment above that POR engine paints are enamels (like what's in the rattle cans... only much thicker) and therefore not hard to remove... when you want to remove them. They are formulated as engine enamels and resist oil and antifreeze. Most paints are affected by DOT-3 brake fluid. I'm sure there are exceptions.