The International Cessna^® 170 Association

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Warranty

That's a big reason NOT to paint them.

So I've often wondered, do black cylinders cool better than other colors or unpainted?

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A solution to painting cylinders that I like is to go to the Marine dealer (or order from West Marine) and buy the common spray can of Mercury black paint. It's thin enough to hold close to spray into the cyliner fins and get coverage without running, and it's a good match for the Continental black. (and it's a high temp/anti-corrosive engine paint that's designed for both aluminum and steel outdrive units.)

Black assists cooling by radiation, and that's one reason that radiators, intercoolers, etc. are frequently painted that color as well. From some cut-and-paste files I've collected:

"The theory is that black is a better emitter of infrared (heat) energy. A hot engine in a cold surrounding, radiates energy from the hot object to the cold. The amount of radiant cooling is (generally) dependent upon the temperature of the emitter (engine) and how efficient the engine is at radiating energy -- its emissivity. This derives from Kirchoff's Law where good absorbers are also good emitters. Since black is a good absorber of energy (that's why it's black) it's also a good emitter. A black object emits more radiant energy (cools faster) than a white or gold object that emits less radiant energy per unit of time. Painting an engine black increases the amount of radiant energy emitted by the hot engine to its colder surroundings and it will be cooler than a non-black engine."
You can paint your engine any color you like and not notice much difference though, because these engines are mostly cooled by convection rather than radiation. I doubt you'd see more than a few degrees in flight regardless of color.... the most difference would be noticed during ground operations. I personally believe the most common reason engines/radiators/etc are painted black though, is because that color draws less attention to them, and they are easier to keep clean.
I like the older Continental engines in their original black and grey, if only because it is more "correct". It looks odd to me to see a 170 with a TCM gold engine in it. But...you guys know me...

Another point about seeing these things (radiators etc) in black that George didn't mention is black is probably cheaper to make and then buy in quantity at the production plant.

gahorn wrote: I like the older Continental engines in their original black and grey, if only because it is more "correct". It looks odd to me to see a 170 with a CM gold engine in it. But...you guys know me...

I agree George, I like the black and grey also, and thanks for the other info. About 15 years ago I got a "barn find" 1946 Aeronca Chief 11BC 85hp. It had about 350 hours total time and had never been recovered or otherwise messed with. I went through the plane completely and did a lot of research to make it correct to the original.

The plane had the original grey and black engine in like new condition. I had the grey color matched and still have the formula for it in Delstar if anyone is interested. I do not know if Continental only used the same grey color in later years though.

The black color also hides oil leaks. Grey will show the leaks quicker.

John

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I paint the heads and barrels black, that's how they were. I use Dulux or Delstar acrylic enamel and bake them two hours at 200 degrees for a really nice finish. Testing my memory here but I think the intake tubes were also black. I actually had some of the early cast rocker covers and those were black also. But that's the C-85. I have an old overhaul manual for that which shows the colors really well. Ok, but I think it's neat to see how they really were.

Now, what color was the cad plating? (this is a test)

All the aluminum parts were alodined prior to painting in accordance with the TCM ovhl manual. All steel parts were heated with infra-red heaters, then painted with enamel. Black was painted on all cylinders including barrels, heads, and covers. Accy's were painted black also. Cases (crank/accy) were painted grey. Ign harnesses were originally black, but most folks ignore that these days.
The Mercury paint is a gloss, but when painted on cases and cylinders (which were all sandcast or roughed up) it loses a bit of that gloss.

A longtime friend and radiator shop owner/operator told me numerous times that a radiator will cool better if left unpainted. However most folks want them painted black as they "look" better if they are where they can be seen through the grill. He always left his personal ones unpainted. BTW his method of painting them was to cut/thin the black paint with gasoline. OSHA, the city & EPA would have had a fit if they had known

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I prefer to use the exact part number called for whenever possible.
But it may be helpful to know the purpose for which certain types of washers are designed.

Plain washers are inserted under screw heads or nuts to provide a suitable bearing surface while tightening and to protect the component from damage due to rotation of the nut or screw head.
Lock washers are used to prevent loosening due to vibrations, movement or temperature variation. Common types include:
1-single coil spring washers normally made of square section spring steel, cut, twisted and chisel-edged, and best used where a torqued fastener is utilized. May be used in conjuction with a plain washer in bolt, all-thread, nuts, and screws. (Never re-use this type washer in torqued service.);
2-thackerey double coil spring washers made of flat section steel or phosphor bronze;
3-"shakeproof" washers punched from spring steel; also commonly called "star" washers, and mfr'd in both external and internal-toothed versions, primarily used in high-vibration service where marring of a sealing surface is unimportant or where electrical or electrolytic continuity is critical;
4-crinkle washers made from berylium copper and used when a lighter spring pressure is required in friction service;
5-tab washers used when a more positive locking action is required. (The tab is bent up against the nut face, thus preventing it from turning.)

Hope this helps.