To Paint an Engine

[Cole J. 71]

Hello all, I have recently been refreshing the kohler k241s of my '72 Charger 10. I am to the point to start considering paint, and I'm unsure of what is safe for paint and what is not. The main body of the block was painted originally and I plan to repaint that portion at least but my concern is with the cooling fins. Is it safe to paint the iron fins or should I leave them bare to allow more exposure? If painting is safe, what type of paint can I use? I have been considering a heavy duty epoxy paint but would that allow proper cooling? The last thing I want is for my freshly rebuilt engine to have a nuclear meltdown. 

I appreciate the help! 

[roadapples 6,983]

If I  were  painting those fins I  would just mist them for a little color. Not a heavy coat. Just my opinion...

[seuadr 489]

so, i've read a lot about this on motorcycle forums, and the general consensus is that it won't harm anything, but it is also very difficult to get a really good job that doesn't flake because of the rapid heating/cooling cycles.

[Jeff-C175 7,206]

17 minutes ago, Cole J. said:

what type of paint can I use?

 

High Temp of course!  (but you knew that already?)  I think you may be asking about brand names?  I've had good luck with VHT high temp engine paint.  I don't think you'll get the flaking on cast iron.  That happens on aluminum mostly.  You get a real good bond on rusty old cast iron.   

 

You might think about finding a blasting house and having them hit that with walnut shells first.

 

I doubt the paint will affect heat transfer much, if at all.  In fact, if you paint it BLACK you may actually IMPROVE the heat transfer!

 

Edited April 7, 2021 by Jeff-C175

[Achto 29,349]

I paint my engines with the same acrylic enamel that I use to paint the rest of the tractor. The main part of the block gets 3 coats of paint, the cooling fins get 2 coats.

 

I have never had issues with the paint or with cooling. 

No matter what paint you use, it will discolor by the exhaust port.

I always leave my cylinder heads bare aluminum.

[pacer 3,177]

14 minutes ago, Achto said:

I paint my engines with the same acrylic enamel that I use to paint the rest of the tractor. The main part of the block gets 3 coats of paint, the cooling fins get 2 coats.

 

I have never had issues with the paint or with cooling. 

No matter what paint you use, it will discolor by the exhaust port.

I always leave my cylinder heads bare aluminum.

 

Sounds like @Achto does almost exactly the way I do it. 

 

Prolly catch some flack for saying that I 'sand' blast the engine (coal slag) -- I bolt the head on with old gasket, put an old plug in, bolt the pan on, valve cover with gasket, double mask all the 'openings' -- in other words keep the 'sand' out, and get it cleaned. Last couple I've done I left the head in its nicely cleaned aluminum look. If care is taken with masking/blocking inlets it works just fine. And since I use "sunrise red" I put about 3 coats on for a really nice looking engine. As mentioned there will be some browning around the exhaust and somewhat around the head, with whatever you use.

[The Tuul Crib 7,339]

I did the same thing on my sixteen as 

@Achto did.Left  the head bare aluminum

Color on the rest.

[ranger 1,798]

If you wanted to paint the fins black, wood burner stove rattle can black is quite good for this application. I’ve used it before for exhaust pipes, etc.

Doug.

p.s. This stuff dries ok, but actually uses the heat from the stove/engine/exhaust, whatever, to fully cure.

Edited April 7, 2021 by ranger

[little red riding horse 223]

VHT rattle cans are great , they do primer , colour and clear coat .... 

 

[ranger 1,798]

In the ‘1960s’ we used to paint the cylinder barrels on our motorbikes  (British), with “ Blackboard” paint. It was cheap, and seemed to withstand the heat ok.

 

Doug.

[oliver2-44 10,678]

4 hours ago, pacer said:

 

Sounds like @Achto does almost exactly the way I do it. 

 

Prolly catch some flack for saying that I 'sand' blast the engine (coal slag) -- I bolt the head on with old gasket, put an old plug in, bolt the pan on, valve cover with gasket, double mask all the 'openings' -- in other words keep the 'sand' out, and get it cleaned. Last couple I've done I left the head in its nicely cleaned aluminum look. If care is taken with masking/blocking inlets it works just fine. And since I use "sunrise red" I put about 3 coats on for a really nice looking engine. As mentioned there will be some browning around the exhaust and somewhat around the head, with whatever you use.