X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [129.116.87.142] (HELO MAIL01.austin.utexas.edu) by logan.com (CommuniGate Pro SMTP 4.3.5) with ESMTP id 1024613 for flyrotary@lancaironline.net; Tue, 28 Jun 2005 09:19:30 -0400 Received-SPF: none receiver=logan.com; client-ip=129.116.87.142; envelope-from=mark.steitle@austin.utexas.edu X-MimeOLE: Produced By Microsoft Exchange V6.5.7226.0 Content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----_=_NextPart_001_01C57BE3.E90C21EB" Subject: RE: [FlyRotary] Re: Coolant Leak Date: Tue, 28 Jun 2005 08:18:44 -0500 Message-ID: <87DBA06C9A5CB84B80439BA09D86E69E016C1AAE@MAIL01.austin.utexas.edu> X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: [FlyRotary] Re: Coolant Leak Thread-Index: AcV7iTKWfNiEzwq2QdWsOcCnlTVAWQAVxaSg From: "Mark R Steitle" To: "Rotary motors in aircraft" This is a multi-part message in MIME format. ------_=_NextPart_001_01C57BE3.E90C21EB Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Hi Ed, I haven't paid real close attention to my coolant pressures up to now. Not seeing anything "unusual", I typically focus on other stuff. Best I recall, my coolant pressure starts at 0 and gradually increases. I have not noticed any quick rise immediately following startup. But then, the coolant pressure sensor is locate at the thermostat housing (no thermostat). So, I'm measuring coolant pressures between the block and radiator. The highest pressure I recall seeing so far is about 24psi after running for 20-30 minutes and temps are in the 212 degree range. I have to admit that I've been ignorant and uninformed as to the need for a cup-o-air in my system and have to this date "filled it to the brim". I guess I need to add a cup-o-air the first chance I get. =20 =20 I don't follow you on the potential damage to the o-rings. The TES o-rings are supposed to be good to 500 degrees (I let you test that theory). They're supposed to be good for 100 degrees over the stock o-rings, so I should have a considerably higher margin of safety here. I would be more concerned with blowing a radiator hose, but I'm using aluminum tubing with Wiggins type couplings, so I don't think I'll be blowing them apart anytime soon. I guess the weakest link in my system is the heater hoses. While they're top of the line Gates hose, I plan on changing to silicone heater hose before first flight. =20 =20 Mark (Happy to hear you got home safely) ________________________________ From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Ed Anderson Sent: Monday, June 27, 2005 9:29 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Coolant Leak =20 Mark, =20 The phenomena which started this thread was the immediate rise in pressure during initial start up in some installations (mine for instance) when all air has been removed from the coolant system. Once my engine warms up the pressure runs around 8 psi and may climb as high as 10psi if temps are higher than 200F. It is true that higher pressure delays the temperature that water boils at - but, higher pressure may also work against your waterpump seal and cause leaks (just a thought). I personally prefer to run at lower coolant pressures since my radiator cap has a max of 21-24 psi. I suspect that while a higher PSI may indeed delay the onset of the coolant boiling - if your engine is that hot - you will probably have cooked something (like "O" rings {:>)).=20 =20 Ed ----- Original Message -----=20 From: Mark R Steitle =20 To: Rotary motors in aircraft =20 Sent: Monday, June 27, 2005 10:07 AM Subject: [FlyRotary] Re: Coolant Leak =20 =20 Ed,=20 Not to stir the swirl pot, but I thought that it was decided some time back that higher pressures were better than lower pressures. The higher pressures are supposed provide more margin of safety before a boil-over occurs, permitting a thinner ethylene-glycol solution and enabling the engine to tolerate higher temps before experiencing catastrophic boiling. So, I'm wondering where this leaves us. Is it better to run at low (7-8 psi) pressures, or high (28-30psi) pressures? =20 Mark S.=20 =20 =09 I agree, Al, inquiring minds at least like a plausible hypothesis and I think the discussion has led to that. Perhaps I'll leave the "cup" of air, just for peace of mind {:>)=20 =09 Ed ------_=_NextPart_001_01C57BE3.E90C21EB Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Hi Ed,

I haven’t paid real close = attention to my coolant pressures up to now.  Not seeing anything = “unusual”, I typically focus on other stuff.  Best I recall, my coolant = pressure starts at 0 and gradually increases.  I have not noticed any quick = rise immediately following startup.  But then, the coolant pressure sensor is locate = at the thermostat housing (no thermostat).  So, I’m measuring = coolant pressures between the block and radiator.  The highest pressure I recall = seeing so far is about 24psi after running for 20-30 minutes and temps are in the = 212 degree range.  I have to admit that I’ve been ignorant and uninformed as to the need for a cup-o-air in my system and have to this = date “filled it to the brim”.  I guess I need to add a cup-o-air the first = chance I get. 

 

I don’t follow you on the = potential damage to the o-rings.  The TES o-rings are supposed to be good to = 500 degrees (I let you test that theory).  They’re supposed to be = good for 100 degrees over the stock o-rings, so I should have a considerably = higher margin of safety here.  I would be more concerned with blowing a = radiator hose, but I’m using aluminum tubing with Wiggins type couplings, = so I don’t think I’ll be blowing them apart anytime soon.  I guess the = weakest link in my system is the heater hoses.  While they’re top of = the line Gates hose, I plan on changing to silicone heater hose before first flight.  =        

 

Mark

(Happy to hear you got home = safely)

From: = Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Ed Anderson
Sent: Monday, June 27, = 2005 9:29 PM
To: Rotary motors in = aircraft
Subject: [FlyRotary] Re: = Coolant Leak

 

Mark,

 

The phenomena which started this thread was the = immediate rise in pressure during initial start up in some installations (mine for instance) when all air has been removed from the coolant system.  = Once my engine warms up the pressure runs around 8 psi and may climb as high as 10psi = if temps are higher than 200F.   It is true that higher pressure delays = the temperature that water boils at - but, higher pressure may also work = against your waterpump seal and cause leaks (just a thought).  I personally = prefer to run at lower coolant pressures since my radiator cap has a max of = 21-24 psi.  I suspect that while a higher PSI may indeed delay the onset = of the coolant boiling - if your engine is that hot - you will probably have = cooked something (like "O" rings {:>)). =

 

Ed

----- Original Message ----- =

From: Mark R Steitle =

Sent: Monday, = June 27, 2005 10:07 AM

Subject: = [FlyRotary] Re: Coolant Leak

 

 

Ed,

Not to stir the swirl pot, but I = thought that it was decided some time back that higher pressures were better = than lower pressures.  The higher pressures are supposed provide more margin = of safety before a boil-over occurs, permitting a thinner ethylene-glycol = solution and enabling the engine to tolerate higher temps before experiencing catastrophic boiling.  So, I’m wondering where this leaves = us.  Is it better to run at low (7-8 psi) pressures, or high (28-30psi) pressures? 

 

Mark S. =

 


I agree, Al, inquiring minds at least like a plausible hypothesis and I = think the discussion has led to that.  Perhaps I'll leave the = "cup" of air, just for peace of mind {:>)

Ed

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