X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [24.25.9.102] (HELO ms-smtp-03-eri0.southeast.rr.com) by logan.com (CommuniGate Pro SMTP 4.3.5) with ESMTP id 1024240 for flyrotary@lancaironline.net; Mon, 27 Jun 2005 22:32:30 -0400 Received-SPF: pass receiver=logan.com; client-ip=24.25.9.102; envelope-from=eanderson@carolina.rr.com Received: from edward2 (cpe-065-188-083-049.carolina.res.rr.com [65.188.83.49]) by ms-smtp-03-eri0.southeast.rr.com (8.12.10/8.12.7) with SMTP id j5S2VgY5016226 for ; Mon, 27 Jun 2005 22:31:43 -0400 (EDT) Message-ID: <006601c57b89$8b1e4540$2402a8c0@edward2> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Engine Rebuild - Coolant Leak Cause Date: Mon, 27 Jun 2005 22:31:52 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0063_01C57B68.03C785F0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2180 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_0063_01C57B68.03C785F0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Could be, Buly suggested the same thing, George. =20 My coolant pressure pump is after the radiators and before the water = pump inlet. So the coolant does have to get through two radiators = before my sensor senses the pressure. Ed ----- Original Message -----=20 From: Echo Lake Fishing Resort (Georges Boucher)=20 To: Rotary motors in aircraft=20 Sent: Monday, June 27, 2005 11:42 AM Subject: [FlyRotary] Re: Engine Rebuild - Coolant Leak Cause Hi! Ed Where is you coolant pressure sender in relation to the water = pump outlet? My theory is that the initial pressure has nothing to do with = temperature, the 13b coolant passages are small,(those A/C condensers = add to the restriction.) upon startup the water pump is trying to move a = immobile wall of coolant , once the coolant returns to the the pump = inlet the flow resistance drops so does the pressure. Georges B.-------Original Message------- From: Rotary motors in aircraft Date: 06/27/05 08:18:00 To: Rotary motors in aircraft Subject: [FlyRotary] Re: Engine Rebuild - Coolant Leak Cause On 6/24/05 3:18 PM, "Ed Anderson" = wrote: Hi John, A couple of things. Tracy and I both discovered that one ALL = the air is out of the coolant system, the coolant pressure may jump to = 21 psi almost immediately upon start up - long before the heat would = cause it to build to that point. At first, I thought "coolant Leak", = however, I could never find any evidence of coolant in the chambers nor = loss of coolant in the system. Talking to Tracy Crook, he reported the = same thing. We came to the conclusion that without a small cushion of = air that the pressure sensor was seeing hydraulic pressure caused by the = pump. With no air cushion even a small disturbance would likely cause = the pressure sensor to indicate high pressure. As the block and = components heated up the coolant volume got a tiny bit larger due to = expansion of parts and the hydraulic pressure quickly decreased. At = least that was the best theory we could come up with at the time. During flight the pressure would quickly decrease until it was = below 10 psi and on cool days would got to zero. On my flight back home (some air still in system), the coolant = pressure never got above 12 psi (right after take off when hottest) and = most of the time ran at 8 psi. So if you are seeing a nominal 10 psi = and only seeing the 25 psi on startup, I don't think you have any = problem especially if no evidence of coolant in exhaust stacks. =20 Ed A Ed, I think that maybe it takes few moments for the pump to = accelerate the mass of coolant inside the cooling system. That's why the = pressure at the pump outlet is high for a while? Buly=20 =20 =20 =20 ------=_NextPart_000_0063_01C57B68.03C785F0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Could be, Buly suggested the same thing, George. 
 
My coolant pressure pump is after the radiators and before the = water pump=20 inlet.  So the coolant does have to get through two radiators = before=20 my  sensor senses the pressure.
 
Ed
----- Original Message -----
From:=20 Echo=20 Lake Fishing Resort (Georges Boucher)
Sent: Monday, June 27, 2005 = 11:42=20 AM
Subject: [FlyRotary] Re: Engine = Rebuild -=20 Coolant Leak Cause

 Hi! Ed
 Where is you coolant pressure sender in relation to = the water=20 pump outlet?
My theory is that the initial pressure has nothing to do = with=20 temperature, the 13b coolant passages are small,(those A/C = condensers=20 add to the restriction.) upon startup the water pump is trying = to move a=20 immobile wall of coolant , once the coolant returns to the the = pump=20 inlet the flow resistance drops so does the pressure.
Georges B.-------Original Message-------
 
From: Rotary motors in=20 aircraft
Date: = 06/27/05=20 08:18:00
To: Rotary motors in=20 aircraft
Subject: = [FlyRotary]=20 Re: Engine Rebuild - Coolant Leak Cause
 
On 6/24/05 3:18 PM, "Ed Anderson"=20 <eanderson@carolina.rr.com> wrote:
Hi=20 John,

A couple of things.  Tracy and I both = discovered that=20 one ALL the air is out of the coolant system, the coolant = pressure may=20 jump to 21 psi almost immediately upon start up - long before = the heat=20 would cause it to build to that point.  At first, I thought = "coolant Leak", however, I could never find any evidence of = coolant in=20 the chambers nor loss of coolant in the system.  Talking to = Tracy=20 Crook, he reported the same thing.  We came to the = conclusion that=20 without a small cushion of air that the pressure sensor was = seeing=20 hydraulic pressure caused by the pump.  With no air cushion = even a=20 small disturbance would likely cause the pressure sensor to = indicate=20 high pressure. As the block and components heated up the coolant = volume=20 got a tiny bit larger due to expansion of parts and the = hydraulic=20 pressure quickly decreased.   At least that was the = best=20 theory we could come up with at the time.

During=20 flight the pressure would quickly decrease until it was below 10 = psi and=20 on cool days would got to zero.

On my=20 flight back home (some air still in system), the coolant = pressure never=20 got above 12 psi (right after take off when hottest) and most of = the=20 time ran at 8 psi.   So if you are seeing a nominal 10 = psi and=20 only seeing the 25 psi on startup, I don't think you have any = problem=20 especially if no evidence of coolant in exhaust stacks.=20  

Ed A

Ed, I=20 think that maybe it takes few moments for the pump to accelerate = the=20 mass of coolant inside the cooling system. That=92s why the = pressure at=20 the pump outlet is high for a while?
Buly=20
 
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