Dave,
My 20B WP housing has a plug in the area that can be removed to let the trapped air escape.  Sounds like way out in left field, but that's what I had to do the last time I filled my cooling system in order to get it to start circulating.  The small hole sounds like a good start, or maybe you could drill/tap a 1/4"NPT in the housing and install a plug like on the 20B housing. 

Mark S.

  At 09:37 PM 4/7/2004 -0700, you wrote:

Mark,  I sealed that passage by welding a plate over it.  So you are right that I probably have air trapped in there.  It shouldn t be enough to prevent circulation, but a small hole would help to get that bit of air out of the system.  I will do that.  There won t be any significant flow through a #40 hole but it will allow the air to get out.

 

One little improvement, now I just need a few more.

 

David Leonard

The Rotary Roster:

http://members.aol.com/_ht_a/rotaryroster/index.html

-----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Mark Steitle
Sent: Tuesday, April 06, 2004 1:00 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Cooling Problem

 

Dave,
One thing that caused me a bunch of head-scratching was the bypass circuit in the water pump housing when first filling the cooling system.  It can prevent the wp impeller from pumping coolant through the engine.  That is where I would look first.  Did you weld and/or plug the hole at the bottom of the thermostat?  If so, you could have air trapped in that cavity.  If you installed a screw-in plug, try removing it and then filling the system, then replace the plug.  If you're running a thermostat, have you removed it to fill the system? 

Mark S.