Mailing List flyrotary@lancaironline.net Message #2792
From: Tracy Crook <lors01@msn.com>
Subject: Re: [FlyRotary] water flow (the quiz)
Date: Wed, 3 Sep 2003 18:51:29 -0400
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Message
 

Greetings again,
 
In the previous post, I labeled the ports on my radiator, and now I'm confusing myself :-)
 
When I was talking to Bruce about my oil temp issues, he suggested that I run the (currently plugged) heater output into the radiator inlet to produce some more coolant flow through the radiator.  This would be in an effort to increase the efficiency of the oil/water heat exchangers when the thermostat is closed, and there's little water flow.  If I prove that I need to lower my temps, I'll try this.  Certainly, water will actually flow from the heater port to the radiator inlet tank, because Bruce said Mazda used to do this with the 1st gen oil/water heat exchangers. 
 
Since water will flow from the engine to the radiator inlet tank, why do they return the heater itself to the radiator outlet side.  This is also true for the AST, and turbo as far as I can tell.  I certainly plumbed my AST and turbo returns back to the radiator outlet tank, so in effect, they bypass the radiator.  The volume of water is small, so it's probably not a big deal, but it just seems odd that they wouldn't return all the water to the same place.  I initially thought that maybe they made an exception for the oil/water heat exchanger return, since it would be picking up heat, and they'd want to pass that through the radiator.  Of course you'd think the same would be true of the turbo water return.  
 
I'm not sure there's really a question here, but if it happens to make sense to anyone, let me know.
 
As for the oil temp saga, I should have an oil temp reading into the engine by this weekend.   
 
Thanks,
Rusty (waiting for oil temp sensor supplies)
 
 
Rusty, I can't concieve of a situation where you would need more oil cooling when the thermostat has not even opened yet. 
 
Your potential problem is simply not having enough coefficient of thermal coupling between oil and water.  If you don't,  none of the proposed changes will work.  Another factor:  If the thermostat is throttling the water flow through the rad due to too much water cooling, the water at the cold end of the rad is *really* cool.  The oil cooler at that end will provide all the cooling the oil could ask for IF there is sufficient thermal transfer capability.
 
Just my opinion but the proposed plumbing changes would be a waste of precious time.
 
Tracy
 
  
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