<VV> alternate fans / Electrics

[jvhroberts at aol.com]

 What you really need, to get better cooling, is a LOT more static pressure. The air velocities under the top shroud don't really matter all that much to impact where the air goes. More static pressure will increase air flow through the fins. 

 

John Roberts
 

 

-----Original Message-----
From: Mel Francis <mfrancis at wi.rr.com>
To: Matt Nall <patiomatt at aol.com>
Cc: virtualvairs <virtualvairs at corvair.org>
Sent: Sat, Mar 16, 2013 7:27 pm
Subject: Re: <VV> alternate fans / Electrics



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


> 
> 
> 
>>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
> 
> ===============================================================================
> 
> 
> Gary,  so far we haven't seen a  12 volt Fan that will make enough 
pressure..... regardless of  the lower shrouds, etc.
> 
> 
> Why some,  Mel Francis and Brian O'neil   use the stock fans with electric 
motors  driving them..
> 
> 
> 
> 
> Here's a case of extreme  deflashing / opening of the heads fin passages..
> 
> 
> 
> 
> 
> 
> Matt Nall
> Charleston, Oregon
> http://tinyurl.com/The-Corvair-Patio
> 
> http://tinyurl.com/Matts-Tech-Pages
> 
> 
> 
> 
> 
> 
> 
> -------------- next part --------------
> A non-text attachment was scrubbed...
> Name: Noah-extreme-deflashing (Medium).jpg
> Type: image/jpeg
> Size: 147806 bytes
> Desc: not available
> Url : http://www.vv.corvair.org/pipermail/virtualvairs/attachments/20130316/b73e68d4/attachment.jpg 

> _______________________________________________
> This message was sent by the VirtualVairs mailing list, all copyrights are the 
property
> of the writer, please attribute properly. For help, mailto:vv-help at corvair.org
> This list sponsored by the Corvair Society of America, http://www.corvair.org/
> Post messages to: VirtualVairs at corvair.org
> Change your options: http://www.vv.corvair.org/mailman/options/virtualvairs 
> _______________________________________________ 
 _______________________________________________
This message was sent by the VirtualVairs mailing list, all copyrights are the 
property
of the writer, please attribute properly. For help, mailto:vv-help at corvair.org
This list sponsored by the Corvair Society of America, http://www.corvair.org/
Post messages to: VirtualVairs at corvair.org
Change your options: http://www.vv.corvair.org/mailman/options/virtualvairs 
 _______________________________________________