X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fmailhost06.isp.att.net ([204.127.217.106] verified) by logan.com (CommuniGate Pro SMTP 5.2.0) with ESMTP id 2756682 for flyrotary@lancaironline.net; Mon, 25 Feb 2008 11:22:00 -0500 Received-SPF: pass receiver=logan.com; client-ip=204.127.217.106; envelope-from=bbradburry@bellsouth.net Received: from arptk8ng400 (adsl-146-123-91.mco.bellsouth.net[72.146.123.91]) by isp.att.net (frfwmhc06) with SMTP id <20080225162117H0600d71toe>; Mon, 25 Feb 2008 16:21:19 +0000 X-Originating-IP: [72.146.123.91] From: "Bill Bradburry" To: "'Rotary motors in aircraft'" References: In-Reply-To: Subject: RE: [FlyRotary] Re: Water pressure Date: Mon, 25 Feb 2008 11:21:24 -0500 Message-ID: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0006_01C877A0.8F274F90" X-Mailer: Microsoft Office Outlook 11 Thread-Index: Ach3wNFcjRCBmr3VTV2G0qcYCLp9ugACEaow X-MimeOLE: Produced By Microsoft MimeOLE V6.0.6000.16545 This is a multi-part message in MIME format. ------=_NextPart_000_0006_01C877A0.8F274F90 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Bob, how is your cooling system set up? I was getting high water = pressures and blowing out of the overflow when I had a pressure cap on the = radiator. I changed that to a radiator cap that has no pressure containment valve = on the radiator, took the overflow hose from the radiator to the bottom of = an overflow bottle (a modified fire extinguisher) which has a 23# cap on = it. The overflow from this bottle vents to the outside, but so far, has = never vented. The bottle is about =BE full of coolant. This eliminated my = high pressures and stopped all the blowing out of the overflow. I think that this is similar to the way most of the cooling systems are set up on the list. =20 The air in the top of the overflow bottle prevents the hydraulic lock = that Ed is talking about below, but ensures that there is no air in the circulating coolant. This didn=92t solve all my cooling problems, but = it eliminated one of them. :>) =20 Bill B =20 _____ =20 From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of bmears9413@aol.com Sent: Monday, February 25, 2008 10:11 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Water pressure 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. =20 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. =20 Ed ----- Original Message -----=20 From: BMears9413@aol.com=20 To: Rotary motors in aircraft=20 Sent: Sunday, February 24, 2008 11:52 PM Subject: [FlyRotary] Water pressure =20 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? =20 Bob Mears=20 Supermarine Spitfire _____ =20 Delicious ideas to please the pickiest eaters. Watch the video on AOL Living. _____ =20 size=3D2 width=3D"100%" align=3Dcenter>=20 More new features than ever. Check out the new AOL Mail ! ------=_NextPart_000_0006_01C877A0.8F274F90 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Bob, how is your cooling system set up?=A0 I was getting high = water pressures and blowing out of the overflow when I had a pressure cap on = the radiator.

I changed that to a radiator cap that has no pressure = containment valve on the radiator, took the overflow hose from the radiator to the bottom = of an overflow bottle (a modified fire extinguisher) which has a 23# cap = on it. The overflow from this bottle vents to the outside, but so far, has never = vented.=A0 The bottle is about =BE full of coolant.=A0 This eliminated my high = pressures and stopped all the blowing out of the overflow.=A0 I think that this is = similar to the way most of the cooling systems are set up on the = list.

 

The air in the top of the overflow bottle prevents the hydraulic = lock that Ed is talking about below, but ensures that there is no air in the circulating coolant.=A0 This didn’t solve all my cooling problems, = but it eliminated one of them.=A0 :>)

 

Bill B

 

From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of bmears9413@aol.com
Sent: Monday, February = 25, 2008 10:11 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: = Water pressure

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.

= size=3D2 width=3D"100%" align=3Dcenter>

More new features than ever. Check out the = new AOL Mail!

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