[FC] lower shrouds

[Ken Hand]

 Now lets not go to extremes when thinking about this. "Dead cold" will never happen if a Corvair engine runs.

Unless you own a vehicle with a temp gauge you have no idea how hot your engine really is. Then how hot is hot and how cold is cold?

The one thing about a Corvair engine is it will operate at a temperature no matter what you do to it, with shrouding or without. The question is what is a good operating temperature. I have NEVER been able to get an engine to operate on the road less than 200 degrees indicated with a stock gauge. I have to point out there are many aftermarket gauges out there and almost all will read less temperature than the factory gauge because they are not as near the real heat as the stock sender unit. The stock sender unit is only 3/16" from the actual combustion process in a 140 hp engine, all others are much farther away and therefore much cooler reading. How hot is hot? This is limited by how hot the aluminum can get and still stay together. What number is that? Well according to our safety engineers at GM they put the red line at 550 degrees. Why?  Because aluminum will get very soft in another 200 degrees or so.

The good operating temp range for the Corvair engine is 250 to 500 degrees. Will the engine run good within these temp extremes? Yes and no. We all know the hotter the engine the more prone it is to detonation but what is the ideal operation temp? I am not sure that can ever be determined. What has been shown most recently for a good operating range is 275 - 400 degrees. Anywhere in that range and your engine should operate normally.

Without going into a full blown tech article, those running without shrouds will be in the 275-350 degree temp range and those running shrouds will be in the 300-450 degree range depending on how you use your engine. The FC will be at the higher end of the ranges because of the large frontal area.

No one here is trying to get anyone to run without the lower heater shrouds on.  If you have no problems everyone is happy. For those that are running on the high side for temp and would like to try and cool things down a little, removing the heater shrouds is the first step and the easiest. An engine that warms up fast and runs in the middle lower temps will last longer than running at either extreme ends of the temp scale.

Do the heater shrouds need to be in place for the engine to operate in a normal temp range? No. The heater shrouds are only for creature comforts, aka heater system.

 

Ken Hand
248-613-8586
www.corvairmechanic.com

http://s186.photobucket.com/albums/x118/vairmech/Viet%20Nam%20Pictures%201971/


 

 

-----Original Message-----
From: Ron <ronh at owt.com>
To: corvanatics <corvanatics at corvair.org>; Ken Hand <vairmech at aol.com>
Sent: Tue, Jan 3, 2012 11:21 pm
Subject: Re: [FC] lower shrouds


I get the idea from some of the discussion that the ultimate goal is to 
increase the cooling and that a dead cold or supercooled engine must be 
better than the way GM designed it.  That's absolute nonsense, of course, 
and any parts installed to get the operating temperature up to where it 
should be were put there for valid reasons.  The fact that off roaders 
remove the lower shrouds along with most of the body doesn't mean anything 
to me since I, along with most others, I assume, prefer to run it as a car. 
And, as a car, it runs very well with full shrouds and thermostats when the 
ambient temperature is 110 or more.  What more could you want of a 50 year 
old car or van?
RonH