(fwd) (re: engine tin painting

[Veeduber <Veeduber@aol.com>]

In a message dated 97-12-31 01:40:27 EST, you write:

<< I would like to take 
 issue with you on your analysis of the effect of color on the 
 cooling....
 
 The engine cools by both radiation and conduction.  Radiated heat 
 will be absorbed by the tin itself, but only if the tin is a 
 good absorber.  Most of this heat will be transferred to the 
 layer of air that flows next to the tin.... >>
 
Jim,

I'm sure you're correct.

I'm equally sure that it doesn't really matter, for the reason you yourself
have stated in your message.

The next time you're roaring down the road at sixty miles an hour, climb into
your engine compartment and feel the tin-ware.  (You may also do this while
the engine is running on a test-stand if you wish.)

You'll find that you can rest your hand on the cylinder-head tin-ware just
above the exhaust stacks (the hottest tin-ware on the engine) with very little
discomfort, aside from your unusual position (assuming you're roaring down the
road at sixty miles an hour, etc).   

It appears that so long as the blower is spinning the shrouding does not
absorb an appreciable amount of heat.  Or, if it does, it is immediately
carried away by the air-flow within the shrouding.

Now consider this:  Let us say that you treat your shrouding with something
that makes it transparent to radiated thermal energy, or as nearly so as you
can get it.  Where does that radiated heat go?

I suggest it goes into your engine compartment, and from there, into the
blower... and back over your engine.

Personally, I'm content to follow Volkswagen's lead when it comes to the color
of the engine's tin-ware.  Over the years I've seen stock VW automotive and
industrial engines painted gray, black, yellow, green, olive drab and red.  

And now Propane Blue, of course :-)

-Bob Hoover