<VV> alternate fans / Electrics

[Mel Francis]

Whether you use electric or mechanical drive from the engine, the only fan I would ever consider for the Corvair engine is the stock fan. The pressure from the fan is only part of it. If you take a look at the top shroud on the engine, the downward-radiused part of the cover, just before the spark plug location is designed to take the high-speed air coming radially out of the fan and direct it down, right into the head fins, at the area of the highest heat, the exhaust valve seats.

For a fan installation to cool correctly, you really need that high-speed, high pressure air to hit the fins in that spot for any engine longevity. Flat fans mounted to the top of the shroud don't pressurize that specific area and have a problem dissipating heat, when the engine is under a sustained load, during regular driving. That's also why de-flashing is so important, right in that area especially, on each head.

Recently, I've been considering an internal 90 degree, geared shaft drive to the stock fan through a modified engine top cover. It involves some tight engineering, but it looks like it can all be fitted. The shaft would then extend back to the rear pulley, over a modified alternator bracket and connect to a short belt that takes its drive from an A/C pulley, mounted to the rear harmonic balancer, like the vertical Porsche-type fan does. This one modification could make any Corvair rock-solid cooling-reliable, especially those dedicated to speed events, without the almost 'traditional' embarassment of thrown belts.

I didn't invent this approach, our German friends did, about 50 years ago. 

Check out this inspirational drawing: 
http://www.flickr.com/photos/mel_francis/8562361841/in/photostream

Mel Francis


----- Original Message ----- 
From: "Matt Nall" <patiomatt at aol.com>
To: <virtualvairs at corvair.org>
Sent: Saturday, March 16, 2013 3:59 PM
Subject: Re: <VV> alternate fans / Electrics


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>>From many of the electric fan articles I have read there is mention of too much 
> back pressure with the lower shrouds in place. Would it be helpful to install 
> small electric fans at the outlets to help pull the air through? These fans and 
> perhaps the top fan could be triggered by the thermostats opening the exhaust 
> doors. GMoore
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> Gary,  so far we haven't seen a  12 volt Fan that will make enough pressure..... regardless of  the lower shrouds, etc.
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> Why some,  Mel Francis and Brian O'neil   use the stock fans with electric motors  driving them..
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> Here's a case of extreme  deflashing / opening of the heads fin passages..
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> Matt Nall
> Charleston, Oregon
> http://tinyurl.com/The-Corvair-Patio
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> http://tinyurl.com/Matts-Tech-Pages
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