Engineers...

[Scott Fisher <sefisher@domain.elided>]

In V7 #902, Jon (MPBTGlim@domain.elided) writes, "This goes the "ALFA
ENGINEERS ARE SMARTER THAN WE THINK" category!"

So last summer, as I was sorting the new-to-me 1983 Audi Coupe GT that
is now my wife's car, one of the things the previous owner said to me
was that the radiator fan was stuck in the On position, which he didn't
think would cause a problem.  I noticed that the coolant was pretty
nasty, so I decided to drain it, flush it, and use my standard witch's
brew of distilled water, coolant, and Redline.

On the way to the Historics last year, in 68 degree weather at about 85
mph in caravan with twelve or thirteen other Audis, it was on the verge
of overheating.  Whaddupwiddat? I asked.  I got to the gate and was
stuck in an hour-long queue to get to the parking lot, and temperature
was lower than normal.  Huh?  When it SHOULD overheat, it doesn't, and
when it SHOULD run cool, it doesn't.

Lunch with another car-savvy friend resulted in the comment, "I can't
think of any reason that would happen, unless the thermostat's on the
input side of the engine and you're just running too cool..."  Sure
enough, the thermostat's on the water pump's inlet housing, backwards
from every car I've ever worked on, including both my Alfa 4-cylinders.  

Having the radiator running *too* cool meant the water acted as a heat
sink, the thermostat never opened fully, and the engine ran hot. 
Conclusion: I filled the system with the factory-recommended coolant,
replaced the failed fan switch, radiator cap and the overflow hose with
new stock parts from the dealer, and have had flawless cooling since.  

At the time, I made the more-than-a-little-smart-assed comment that
after all the old British sports cars I'd owned, it had been many years
since I'd owned a car that had been designed by engineers who knew more
about cars than I do.  The grain of truth in there is that a lot of us
"shade-tree" types learned a tremendous amount about working on and
improving cars of the Fifties and Sixties, but which had been designed
using engineering from the Thirties and Forties.  And while the laws of
physics themselves haven't changed in the intervening decades, the
methods and tools that engineers choose to exploit them have.

The sum of all this introspection has been the realization that some of
the tricks we learned, tricks that legitimately work on a cast-iron
pushrod four with three main bearings and siamesed intake and exhaust
ports, and which may in turn have been a refinement of a block that
started out life with a thermosyphon cooling system, side-mounted valves
and babbitted big-end bearings, may not work on an all-alloy block with
steel liners, a high-pressure oiling system, and inverted bucket tappets
driven directly by two overhead cams.  The hard part is to know which of
these tricks work, and which don't, and to find this out without
destroying too many motors.

Which leads to my Philosophical Observation of the Day:  Human beings
never really know anything.  Whenever we're confronted with a new
situation, we make up stories about it, and we keep making up stories
till we find one that works.  Then we stop making up stories and declare
that we know this situation.  The next time we find a similar situation,
we use the same story that we stopped with before.  If it doesn't work,
we change things in the story one by one till it works again, and then
we say that we know *even more*.  And if the story works, then we decide
we were right all along, and we'll never make up another story for that
situation as long as we live, and we'll kill anyone who claims that our
story is anything but the literal truth.

- --Scott "And the Zen master knows that this, too, is a story" Fisher

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