X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from imo-d21.mx.aol.com ([205.188.144.207] verified) by logan.com (CommuniGate Pro SMTP 5.2.0) with ESMTP id 2756551 for flyrotary@lancaironline.net; Mon, 25 Feb 2008 10:12:20 -0500 Received-SPF: pass receiver=logan.com; client-ip=205.188.144.207; envelope-from=BMears9413@aol.com Received: from BMears9413@aol.com by imo-d21.mx.aol.com (mail_out_v38_r9.3.) id q.d5b.1f31a0f4 (37128) for ; Mon, 25 Feb 2008 10:11:17 -0500 (EST) Received: from webmail-md07 (webmail-md07.webmail.aol.com [64.12.170.145]) by cia-ma02.mx.aol.com (v121.4) with ESMTP id MAILCIAMA022-910847c2da9414c; Mon, 25 Feb 2008 10:11:16 -0500 References: To: flyrotary@lancaironline.net Subject: Re: [FlyRotary] Re: Water pressure Date: Mon, 25 Feb 2008 10:11:17 -0500 X-AOL-IP: 65.182.71.8 In-Reply-To: X-MB-Message-Source: WebUI MIME-Version: 1.0 From: bmears9413@aol.com X-MB-Message-Type: User Content-Type: multipart/alternative; boundary="--------MB_8CA45D7CDE0795C_D3C_3EFF_webmail-md07.sysops.aol.com" X-Mailer: AOL Webmail 34032-STANDARD Received: from 65.182.71.8 by webmail-md07.sysops.aol.com (64.12.170.145) with HTTP (WebMailUI); Mon, 25 Feb 2008 10:11:17 -0500 Message-Id: <8CA45D7CDE0795C-D3C-1F09@webmail-md07.sysops.aol.com> X-Spam-Flag: NO ----------MB_8CA45D7CDE0795C_D3C_3EFF_webmail-md07.sysops.aol.com Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii" Cool deal...thanks guys. I have a 30lb. cap and havent let it get there yet to see if it blows out to the overflow tank. I keep thinking that if I had a regular automotive 15lb. cap it would already be pushing by that and its jsut idleing. -----Original Message----- From: Ed Anderson To: Rotary motors in aircraft Sent: Mon, 25 Feb 2008 6:59 am Subject: [FlyRotary] Re: Water pressure Bob, if there is no air in your coolant system, you may be observing an hydraulic lock type phenomena.? My water pressure will immediately zoom to 21 psi on engine start up.? As the engine warms up the pressure drops back down.? My understanding is that with no air and the incompressible nature of a liquid - that even small perturbations anywhere in the system can cause the sensor to signal pressure.? As the engine warms and a very small amount of expansion in block, rad cores, lines etc. happens that is enough increase in volume of the?"containment" ?for the pressure to lower. ? This is why some folks recommend leaving a small amount of air under the cap.? If you are not seeing oil in your coolant or bubbles then its unlikely you have a busted O ring. ? Ed ----- Original Message ----- From: BMears9413@aol.com To: Rotary motors in aircraft Sent: Sunday, February 24, 2008 11:52 PM Subject: [FlyRotary] Water pressure I ran my 20B at idle, till about 160 degrees. My water pressure rose up to 23 lbs. That seems excessive to me, but I've never watched water pressure before. I've bled the block a couple of times and I dont feel like I have an air lock. Heat is even throughout the radiator. I was a bit worried about compression leaking into the cooling chamber, but I'm not loosing any water, the plugs aren't wet, and it starts flawlessly each time. Hot or cold. Recon I'm all worried about nothing? ? Bob Mears Supermarine Spitfire Delicious ideas to please the pickiest eaters. Watch the video on AOL Living. ________________________________________________________________________ More new features than ever. Check out the new AOL Mail ! - http://webmail.aol.com ----------MB_8CA45D7CDE0795C_D3C_3EFF_webmail-md07.sysops.aol.com Content-Transfer-Encoding: 7bit Content-Type: text/html; charset="us-ascii" Cool deal...thanks guys. I have a 30lb. cap and havent let it get there yet to see if it blows out to the overflow tank. I keep thinking that if I had a regular automotive 15lb. cap it would already be pushing by that and its jsut idleing.


-----Original Message-----
From: Ed Anderson <eanderson@carolina.rr.com>
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Sent: Mon, 25 Feb 2008 6:59 am
Subject: [FlyRotary] Re: Water pressure

Bob, if there is no air in your coolant system, you may be observing an hydraulic lock type phenomena.  My water pressure will immediately zoom to 21 psi on engine start up.  As the engine warms up the pressure drops back down.  My understanding is that with no air and the incompressible nature of a liquid - that even small perturbations anywhere in the system can cause the sensor to signal pressure.  As the engine warms and a very small amount of expansion in block, rad cores, lines etc. happens that is enough increase in volume of the "containment"  for the pressure to lower.
 
This is why some folks recommend leaving a small amount of air under the cap.  If you are not seeing oil in your coolant or bubbles then its unlikely you have a busted O ring.
 
Ed
----- Original Message -----
Sent: Sunday, February 24, 2008 11:52 PM
Subject: [FlyRotary] Water pressure

I ran my 20B at idle, till about 160 degrees. My water pressure rose up to 23 lbs. That seems excessive to me, but I've never watched water pressure before. I've bled the block a couple of times and I dont feel like I have an air lock. Heat is even throughout the radiator. I was a bit worried about compression leaking into the cooling chamber, but I'm not loosing any water, the plugs aren't wet, and it starts flawlessly each time. Hot or cold. Recon I'm all worried about nothing?
 
Bob Mears
Supermarine Spitfire



Delicious ideas to please the pickiest eaters. Watch the video on AOL Living.
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