powder coat chief cylinders

[cdf6333]

Hi all, couldn't find anything about this so I'll ask. I've had my 46 Chief since 71 and have 54K miles since initial restro in 72-78. Nothing really goes bad except the cylinders get rusty looking after 4-5 years. I know a few guys tried powder coating cylinders and I'm wondering if it holds up for the long haul. Does HD powder coat theirs these days? Does anyone have 4 or more years and 5,000 or more miles on powder coated cylinders? The powder coater doesn't recommend it, why?
Thanks
Bob Courboin, now in sunny Florida

[fabercycle]

It would be my guess that powdercoat will insulate your fins from doing it's job cooling the engine. According to the HD factory, a thin, dull, black coating works the best to help the fins transfer heat to the air.

[larry]

I powder coated the cylinders on a knuck and on a "K". I don't have the miles or years that you want to hear, but I've experienced no issues to date.

[cdf6333]

The new Harleys all have powder coated cylinders, right? I know that OHV engines don't get as hot as our Flatties and a painter mentioned that powder coating will melt (?) at about 400 degrees. Anyone ever, or could ya, check the cylinder temperature of a late Chief? My Chief is down cause of accident, (Dances with Buicks). Or does anyone have more temperature related info on powder coating?
I know Eli Sentman did his 48 Bonne years ago and they looked great. I think 80% gloss (?).
If this works, it'll be a huge help, at least to me who magnetically attracts rain at the radius of my voyage every time.

[larry]

Caswell, and others, offer high temp powder for exhaust systems. I'm using it successfully. I've used standard polyester powder on exhaust, and it doesn't last. It starts flaking off at the bends. It doesn't melt once cured. The high temp, however, looks as good as it did when installed. I used standard polyester on "K" (sidevalve) cylinders, and there's no evidence of deterrioration at the exhaust ports after about 1500 miles. Time will tell.

[cdf6333]

Thanks Larry, I'm just a little confused. Where did you successfully use the "high temp powder"? And do you remember what color ( % gloss ?) you used on the cylinders? Was sandblasting good enough on the cylinders for prep? Thanks again, this is huge help!

[larry]

The high temp I've used only for exhaust. I was simply pointing out that high temp exists. On cylinders, I use semi gloss, standard polyester, but I've no reason to believe that gloss wouldn't work as well. Sandblasting works as well with powder as it does with paint, but on cylinders won't remove the hidden rust. I follow with a metal prep (phosphoric acid) bath, mechanical scrubbing, baking, then re-blasting. That done, paint or powder will last a very long time.

[ChiefTwoKicks]

I agree with Fabercycle, we all know that heat kills. And I'm sure many have also experienced cracked cylinders around the valve seats. I wouldn't risk it for the sake of looks or maybe a little more maintainance after 50k, geez !! I use a high quality high temp stove black or BBQ flat black paint. and I use a small modeling paint brush, by hand. Sure it takes a bit longer to get between the fins, but I'm happy with the results. Seems to last many years. Disclaimer: I live in sunny SoCal, so we don't get the humidity like those in Florida.

[larry]

Is there evidence that powder insulates more, or less, than paint?