X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from EXHUB003-2.exch003intermedia.net ([207.5.74.29] verified) by logan.com (CommuniGate Pro SMTP 5.2.10) with ESMTPS id 3330558 for flyrotary@lancaironline.net; Thu, 04 Dec 2008 11:06:12 -0500 Received-SPF: none receiver=logan.com; client-ip=207.5.74.29; envelope-from=jwhaley@datacast.com Received: from EXVMBX003-5.exch003intermedia.net ([207.5.74.45]) by EXHUB003-2.exch003intermedia.net ([207.5.74.29]) with mapi; Thu, 4 Dec 2008 08:05:36 -0800 From: Jeff Whaley To: Rotary motors in aircraft Date: Thu, 4 Dec 2008 08:05:36 -0800 Subject: RE: [FlyRotary] Oil Pressure measuring point Thread-Topic: [FlyRotary] Oil Pressure measuring point Thread-Index: AclWEiq335aBoHsyTESwk5ZDDaXDkQABbx0w Message-ID: References: In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US Content-Type: multipart/alternative; boundary="_000_C03ABB0A7362B84BB53D544B3C305E0ED132DC50F4EXVMBX0035exc_" MIME-Version: 1.0 --_000_C03ABB0A7362B84BB53D544B3C305E0ED132DC50F4EXVMBX0035exc_ Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable I've been reading the exchanges between Ed, Bobby and now Tracy. Presently my system measures both oil temperature and oil pressure in the l= ine between engine (high on rear iron, near filter) and PSRU. I don't see w= hat Bobby reports;, rather I see 70 psi when cold no matter what rpm. As oi= l temperature rises I see steps in oil pressure rpm-dependent. If I understand correctly, to see the steady-state 70-80 psi oil return, I = would have to tap into the one-piece 5/8" braided hose running from my oil = cooler to back to the front cover? Jeff From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Beh= alf Of Ed Anderson Sent: Thursday, December 04, 2008 8:13 AM To: Rotary motors in aircraft Subject: [FlyRotary] Oil Pressure was RE: [FlyRotary] Re: New Engine Break = In with Gearbox -- for Tracy Hi Bobby, Ok, if I understand your set up correctly, you are measuring oil pressure B= EFORE the oil filter or the oil cooler - right out of the engine? If that = is correct continue to read - if I misunderstood then this may not be appli= cable. Your oil pressure sensor location may account for what you are seeing. Mos= t oil pressure references are measured as the oil pressure goes back into t= he engine. You appear to be measuring it at the opposite end of the lubric= ation system compared to where most measure it. The reason for choosing the oil inlet to the engine point for pressure mea= surement is that point is where lubrication system is providing pressure fo= r the main bearings - so an important reason the pressure is of most intere= st at that point. It really doesn't matter (not quite true - you do need th= e pump to be producing pressure) what your oil pressure is on the output e= nd of the pump - if the oil pressure is not sufficient on the end where it= flows back into the engine - where the lubrication system feeds the beari= ngs - then you could fry your bearings. An example - lets say your pump is good, but your oil filter or oil cooler = becomes partially blocked impeding flow severely. If you are measuring pre= ssure before those points you would likely see your oil pressure increasing= (due to the blocked flow) - which could give you a false sense of security= - because your bearings could be starving for oil due to the blocked flow. But, if your pressure sensor is not on the inflow end of the lubrication sy= stem - you would have no direct indication that your oil pressure has drop = dangerously low. The higher reading you would be getting from the other en= d would probably convince you that all is OK. At least that is a scenario = that I believe is possible. So, In the traditional set up that means that you have pressure drops (Los= ses) through your oil filter and your oil cooler and the normal oil pressur= e after that (assuming a stock oil pressure regulator) is around 70-80 psi = above 4500-5000 rpm (or in that vicinity). The oil pump end has a pressure controller that is supposed to pop and rele= ase pressure if it senses pressure above 150 psi. That is NOT the controll= er that regulates pressure for the system - only a safety release say shoul= d your oil line becomes blocked (of course your bearings wouldn't live very= long if that happened). The oil pressure regulator (normally set for a ma= x of 80 psi in a stock engine) is on the other end of the lubrication syste= m at the point the oil goes back into the engine. The point that provides = oil to the bearings - so perhaps not surprising that the regulator is locat= ed there. The pressure is suppose to be maintained steady by the oil pressure regulat= or- so no matter what volume(flow) of oil (based on rpm) is going through t= he system the pressure is held steady by the oil pressure regulator on the = inflow end. So I suspect that because your oil pressure sensor appears to be on the p= ump end of the system and not on the end where the pressure regulator is lo= cated that you are seeing perturbations to oil pressure (and because you do= n't have the oil filter and cooler drops) and higher oil pressure than most= of us do. Now the pressure drops through the oil filter and oil cooler may not be lin= ear with flow rate (which would dependent on oil pump/engine rpm ) or tempe= rature (viscosity) of the oil. I suspect that the cooler the oil is, the more resistance it finds in flowi= ng through the oil filter and oil cooler. Therefore you would see more pre= ssure on the pump end due to this resistance, but as the oil warmed up and = flow through the filter and cooler easier then the pressure build up before= those components would drop as would your oil pressure. Because of your oil pressure sensor location and the factors I mentioned ab= ove, I would expect you to see higher oil pressure and a wider range to the= perturbations to your oil pressure based on temps than most of us see. Since you are not using the stock Rx-7 oil cooler, then my comments about t= he effect of the thermostat on oil pressure may not be applicable. At least, this is the way it appears to me. Others may have a different vi= ew point Ed Ed Anderson Rv-6A N494BW Rotary Powered Matthews, NC eanderson@carolina.rr.com http://www.andersonee.com http://members.cox.net/rogersda/rotary/configs.htm#N494BW http://www.dmack.net/mazda/index.html ________________________________ From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Beh= alf Of Bobby J. Hughes Sent: Wednesday, December 03, 2008 9:21 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: New Engine Break In with Gearbox -- for Tracy Tracy, With the Advanced EFIS / engine monitor all of the instruments are factory = calibrated and so far have been correct. Oil pressure is being read directl= y out of the engine before the oil filter and oil / water exchanger. I made= a quick run to the airport this afternoon and made another 15 minute groun= d with the inlet ducts blocked. I was able to get the water up to 200F and = climbing and oil to 165F. OAT was 75F Oil pressure varied from 65 at idle t= o 105 psi at 6000 rpm. On earlier ground runs to 7500 rpm I was only able t= o get the oil to 144F and water to 177F. OAT was 65F or less. and oil press= ure in the 110-120 range. Warming the oil up did seem to make a difference. Ed, "Bobby, depending of where your oil pressure sensor is located (before or a= fter the oil cooler - assuming a stock Rx-7 oil cooler with internal thermo= stat). IF you have removed the thermostat in the oil cooler and have not = blocked that thermostat opening, then a lot of the oil will not flow throug= h the several passages through the cooler core. This could mean you are no= t getting the normal pressure drop across the oil cooler which if your sens= or is down stream would mean higher pressure at the sensor - but probably n= ot more than 5 - 10 psi." No thermostat in the oil or water circuits. If the sensor placement is maki= ng a 10 psi difference then the problem may not exist. My remote oil filter= adapter has two inlets and two outlets. I am using the second inlet for oi= l pressure and the second outlet will be used to monitor the before oil coo= ler temp with the EM3. No room at the engine oil pad adapter block for the = pressure sender so this location was easy. It's visible in one of the photo= s. Bobby ________________________________ From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Beh= alf Of Tracy Crook Sent: Wednesday, December 03, 2008 11:31 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: New Engine Break In with Gearbox -- for Tracy Odd problems. Peak Oil pressure should not be significantly affected by te= mperature or oil weight. What is it? Lower viscosity oil is not a solut= ion. Are you sure the instruments are right / calibrated? Tracy On Wed, Dec 3, 2008 at 11:04 AM, Bobby J. Hughes > wrote: I am having a problem getting my oil temps up and oil pressure down without= an oil thermostat. Will try blocking some of the air flow this weekend. Is= 10W-40 or 10W-30 to light for the gearbox during the winter months? I pla= n to run the engine for at least 20 hours on the ground and switch back to = Mobil 1 for first flight. Bobby ________________________________ From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Tracy Crook Sent: Wednesday, December 03, 2008 9:12 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: New Engine Break In with Gearbox -- for Tracy Next best in mineral oil is Shell Rotella. 15W - 50 or similar. Tracy On Wed, Dec 3, 2008 at 9:18 AM, Bobby J. Hughes > wrote: Tracy, What oil do you recommend for breaking in a new engine that is also accepta= ble for the gearbox? Bruce T said to replace the Mobile 1 for 10-15 hours s= o the apex seals will seat. Thanks, Bobby J Hughes __________ Information from ESET NOD32 Antivirus, version of virus signatur= e database 3267 (20080714) __________ The message was checked by ESET NOD32 Antivirus. http://www.eset.com --_000_C03ABB0A7362B84BB53D544B3C305E0ED132DC50F4EXVMBX0035exc_ Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

I’ve been reading the exchanges between Ed, Bobby and = now Tracy.

Presently my system measures both oil temperature and oil pr= essure in the line between engine (high on rear iron, near filter) and PSRU. I don= ’t see what Bobby reports;, rather I see 70 psi when cold no matter what rpm. = As oil temperature rises I see steps in oil pressure rpm-dependent.=

If I understand correctly, to see the steady-state 70-80 psi= oil return, I would have to tap into the one-piece 5/8” braided hose runn= ing from my oil cooler to back to the front cover?

Jeff

 

From: Rotary motors= in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Ed Anders= on
Sent: Thursday, December 04, 2008 8:13 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Oil Pressure was RE: [FlyRotary] Re: New Engine Break In with Gearbox -- for Tracy

 

Hi Bobby,

 

Ok, if I understand your set up correctly, you are measuring oi= l pressure BEFORE the oil filter or the oil cooler – right out of the engine?  If that is correct continue to read – if I misunderstoo= d then this may not be applicable. 

 

Your oil pressure sensor location may account for what you are seeing.  Most oil pressure references are measured as the oil pressure goes back into the engine.  You appear to be measuring it at the oppos= ite end of the lubrication system compared to where most measure it.=

 

 The reason for choosing the oil inlet to the engine point= for pressure measurement is that point is where lubrication system is providing pressure for the main bearings – so an important reason the pressure = is of most interest at that point. It really doesn’t matter (not quite t= rue – you do need the pump to be producing pressure)  what your oil pressure is on the output end of the pump – if the oil pressure is  not sufficient on the end where it flows back into the engine -  where the lubrication system feeds the bearings – then you coul= d  fry your bearings. 

 

An example – lets say your pump is good, but your oil fil= ter or oil cooler becomes partially blocked impeding flow severely.  If yo= u are measuring pressure before those points you would likely see your oil pressure increasing (due to the blocked flow) – which could give you = a false sense of security – because your bearings could be starving for= oil due to the blocked flow.

 

But, if your pressure sensor is not on the inflow end of the lu= brication system – you would have no direct indication that your oil pressure h= as drop dangerously low.  The higher reading you would be getting from th= e other end would probably convince you that all is OK.  At least that i= s a scenario that I believe is possible.

 

So,  In the traditional set up that means that you have pressure drops (Losses) through your oil filter and your oil cooler and the normal oil pressure after that (assuming a stock oil pressure regulator) is around 70-80 psi above 4500-5000 rpm (or in that vicinity). 

 

The oil pump end has a pressure controller that is suppo= sed to pop and release pressure if it senses pressure above 150 psi.  That= is NOT the controller that regulates pressure for the system – only a sa= fety release say should your oil line becomes blocked (of course your bearings wouldn’t live very long if that happened).  The oil pressure = regulator (normally set for a max of 80 psi in a stock engine) is on the other en= d of the lubrication system at the point the oil goes back into the engine. = ; The point that provides oil to the bearings – so perhaps not surprisi= ng that the regulator is located there.

 

The pressure is suppose to be maintained steady by the o= il pressure regulator– so no matter what volume(flow) of oil (based on r= pm) is going through the system the pressure is held steady by the oil pressure regulator on the inflow end.

 

 So I suspect that because your oil pressure  sensor appears to be on the pump end of the system and not on the end where the pressure regulator is located that you are seeing perturbations to oil pres= sure (and because you don’t have the oil filter and cooler drops) and high= er oil pressure than most of us do.

 

Now the pressure drops through the oil filter and oil cooler ma= y not be linear with flow rate (which would dependent on oil pump/engine rpm = ) or temperature (viscosity) of the oil.

 

I suspect that the cooler the oil is, the more resistance it fi= nds in flowing through the oil filter and oil cooler.  Therefore you would= see more pressure on the pump end due to this resistance, but as the oil warmed= up and flow through the filter and cooler easier then the pressure build up be= fore those components would drop as would your oil pressure. 

 

Because of your oil pressure sensor location and the factors I mentioned above, I would expect you to see higher oil pressure and a wider range to the perturbations to your oil pressure based on temps than most of= us see.

 

Since you are not using the stock Rx-7 oil cooler, then my comm= ents about the effect of the thermostat on oil pressure may not be applicable.

 

At least, this is the way it appears to me.  Others may ha= ve a different view point

 

 

Ed

 

Ed Anderson

Rv-6A N494BW Rotary Powered

Matthews, NC

eanderson@carolina.rr.com

http://www.andersonee.c= om

http://members.cox.net/rogersda/rotary/configs.htm#N494BW<= /o:p>

http://www.d= mack.net/mazda/index.html

From: Rotary motors= in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Bobby J. Hughes
Sent: Wednesday, December 03, 2008 9:21 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: New Engine Break In with Gearbox -- for Tra= cy

 

Tracy,

 

With the Advanced EFIS / engine monitor all of the instruments = are factory calibrated and so far have been correct. Oil pressure is being read directly out of the engine before the oil filter and oil / water exchanger. I made a quick run to the airport this afternoon and made anothe= r 15 minute ground with the inlet ducts blocked. I was able to get the water up = to 200F and climbing and oil to 165F. OAT was 75F Oil pressure varied from 65 = at idle to 105 psi at 6000 rpm. On earlier ground runs to 7500 rpm I was only = able to get the oil to 144F and water to 177F. OAT was 65F or less. and oil pressure in the 110-120 range. Warming the oil up did seem to make a difference.

 

Ed,

 

"Bobby, depending of where your oil pressure sensor is located (before or after the oil cooler – assuming a stock Rx-7 oil cooler wi= th internal thermostat).   IF you have removed the thermostat in the= oil cooler and have not blocked that thermostat opening, then a lot of the oil = will not flow through the several passages through the cooler core.  This c= ould mean you are not getting the normal pressure drop across the oil cooler whi= ch if your sensor is down stream would mean higher pressure at the sensor R= 11; but probably not more than 5 – 10 psi."   =

 

No thermostat in the oil or water circuits. If the sensor place= ment is making a 10 psi difference then the problem may not exist. My remote oil filter adapter has two inlets and two outlets. I am using the second inlet = for oil pressure and the second outlet will be used to monitor the before oil cooler temp with the EM3. No room at the engine oil pad adapter block for t= he pressure sender so this location was easy. It's visible in one of the photos.

 

Bobby

 

 

From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Tracy Crook
Sent: Wednesday, December 03, 2008 11:31 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: New Engine Break In with Gearbox -- for Tra= cy

Odd problems.  Pea= k Oil pressure should not be significantly affected by temperature or oil weight.    What is it?  Lower viscosity oil is not a solution.  Are you sure the instruments are right / calibrated?

Tracy

On Wed, Dec 3, 2008 at 11:04 AM, Bobby J. Hughes <<= a href=3D"mailto:bhughes@qnsi.net">bhughes@qnsi.net> wrote:=

I am having a problem getting my oil temps up and oil pressure = down without an oil thermostat. Will try blocking some of the air flow this weekend. Is 10W-40 or 10W-30 to light for the gearbox during the winter months?  I plan to run the engine for at least 20 hours on the ground and switch back to Mobil 1 for first flight. =

 

Bobby

 

From: Rotary motors in aircraft [mailto:flyrotary@lan= caironline.net] On Behalf Of Tracy Crook
Sent: Wednesday, December 03, 2008 9:12 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: New Engine Break In with Gearbox -- for Tra= cy

Next best in mineral oi= l is Shell Rotella.  15W - 50 or similar.

Tracy

On Wed, Dec 3, 2008 at 9:18 AM, Bobby J. Hughes <bhughes@qnsi.net>= wrote:

Tracy,

 

What oil do you recommend for breaking in a new engine that is also acceptabl= e for the gearbox? Bruce T said to replace the Mobile 1 for 10-15 hours so the ap= ex seals will seat.

 

Thanks,

Bobby J Hughes

 

 

 




__________ Information from ESET NOD32 Antivirus, version of virus signatur= e database 3267 (20080714) __________

The message was checked by ESET NOD32 Antivirus.

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