X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sat, 01 Mar 2008 11:53:57 -0500 Message-ID: X-Original-Return-Path: Received: from mta9.adelphia.net ([68.168.78.199] verified) by logan.com (CommuniGate Pro SMTP 5.2.0) with ESMTP id 2772313 for lml@lancaironline.net; Sat, 01 Mar 2008 06:46:48 -0500 Received-SPF: pass receiver=logan.com; client-ip=68.168.78.199; envelope-from=glcasey@adelphia.net Received: from [75.82.216.175] by mta9.adelphia.net (InterMail vM.6.01.05.02 201-2131-123-102-20050715) with ESMTP id <20080301114606.MICT10598.mta9.adelphia.net@[75.82.216.175]> for ; Sat, 1 Mar 2008 06:46:06 -0500 Mime-Version: 1.0 (Apple Message framework v753) In-Reply-To: References: Content-Type: multipart/alternative; boundary=Apple-Mail-31-578982169 X-Original-Message-Id: <215BCC07-0126-4E2D-BA6A-3365B3B2536D@adelphia.net> From: Gary Casey Subject: Re: Oil Temps and Oil Doors X-Original-Date: Sat, 1 Mar 2008 03:46:05 -0800 X-Original-To: "Lancair Mailing List" X-Mailer: Apple Mail (2.753) --Apple-Mail-31-578982169 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed In my opinion a "low" oil temp like 150F is not a particular worry. I would wonder if the vernatherm is working correctly - your OAT's were not particularly low - what would happen if they were -20, not unheard of at high altitudes in the winter? Anyway, operating with the temperature lower than "normal" will increase engine friction due to the higher viscosity of the oil, but with the semi-synthetic that effect is not as large as if you were running a single-weight mineral oil. Yes, the lower oil temperature reduces the evaporation of water from the oil, but even 150 isn't too bad although 180 would be better and 200 or more would be best. Yes, changing oil a little more often in the winter might be a good thing, but you mentioned a 25-hour oil change interval, which I would consider to be "drastically" short, especially with a synthetic blen. With a good engine oil change intervals of at least 50 hours and even 100 hours would make sense. A good way to judge the correct interval is to look at the oil - if it looks "ugly" it might be time to change it. Too much water will turn it a milky, brown color and in that case you can either change the oil or run the engine for a while with the oil hot to cook out the water. An opaque gray color means it is contaminated with lead oxide - been running really rich? If the oil turns black it might be time to change oil, at least after a while. My rule of thumb is that I keep the oil in there twice as long as it takes to turn black (how black? I don't know) or until 50 hours or so. With my new engine the oil is still relatively clear at 40 hours, so I should wait until at least 80 hours to change it (EXXON Elite), but I'll probably get impatient at about 50. In my old Cessna TR182 the book said to change the filter at 50 and the oil at 100, but I figured if I went to the trouble to change the filter I might as well change the oil. The plane was used regularly, so corrosion wasn't much of an issue and I would use the 50-hour mark as a time to start to think about changing it - the actual intervals varied between 50 and 80. Bottom line: I don't subscribe to the idea that changing oil really often is "cheap insurance" - insurance is only cheap if it actually insures against something and if the oil hasn't been in there for more than 6 months or so and still looks good there is really nothing to be gained by changing it. I feel that any servicing is often a bigger risk - are all the bolts tight, was there anything left off, etc. All just my opinion, Gary Casey On Mar 1, 2008, at 3:01 AM, Lancair Mailing List wrote: > > From: "Douglas Brunner" > Date: February 29, 2008 9:03:45 PM PST > To: lml@lancaironline.net > Subject: Oil Temps and Oil Doors > > > On a recent trip from Florida to Tennessee I observed oil temps in > the 150s. > > My engine is an IO-550N built by Monty Barrett. I decided not to > install a remotely controlled oil door because I had been told that > low oil temps were rarely/never a problem in the Legacy. My > experience differs. > > When I started the flight OATs (8000) ft were in the 40s and oil > temps were in the 180s. But by the time I finished OATs (8000) > were in the 20s and oil temps were in the 150s. Related to and > probably partially the cause of the problem was my use of a low > power setting (2300 RPM, no ram air, 30deg LOP) to extend range. > > Can low oil temps shorten TBO/damage the engine? > Even with regular 25 hour oil changes using Exxon Elite? > Should I go to the trouble to retrofit a remote oil door, or just > change my oil at a shorter interval? > > Enquiring minds wish to know. > > D. Brunner --Apple-Mail-31-578982169 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=ISO-8859-1 In my opinion a "low" oil temp like 150F is not a particular worry. =A0I = would wonder if the vernatherm is working correctly - your OAT's were = not particularly low - what would happen if they were -20, not unheard = of at high altitudes in the winter? =A0Anyway, operating with =A0the = temperature lower than "normal" will increase engine friction due to the = higher viscosity of the oil, but with the semi-synthetic that effect is = not as large as if you were running a single-weight mineral oil. =A0Yes, = the lower oil temperature reduces the evaporation of water from the oil, = but even 150 isn't too bad although 180 would be better and 200 or more = would be best. =A0Yes, changing oil a little more often in the winter = might be a good thing, but you mentioned a 25-hour oil change interval, = which I would consider to be "drastically" short, especially with a = synthetic blen. =A0With a good engine oil change intervals of at least = 50 hours and even 100 hours would make sense. =A0A good way to judge the = correct interval is to look at the oil - if it looks "ugly" it might be = time to change it. =A0Too much water will turn it a milky, brown color = and in that case you can either change the oil or run the engine for a = while with the oil hot to cook out the water. =A0An opaque gray color = means it is contaminated with lead oxide - been running really rich? =A0If= the oil turns black it might be time to change oil, at least after a = while. =A0My rule of thumb is that I keep the oil in there twice as long = as it takes to turn black (how black? =A0I don't know) or until 50 hours = or so. =A0With my new engine the oil is still relatively clear at 40 = hours, so I should wait until at least 80 hours to change it (EXXON = Elite), but I'll probably get impatient at about 50. =A0In my old Cessna = TR182 the book said to change the filter at 50 and the oil at 100, but I = figured if I went to the trouble to change the filter I might as well = change the oil. =A0The plane was used regularly, so corrosion wasn't = much of an issue and I would use the 50-hour mark as a time to start to = think about changing it - the actual intervals varied between 50 and 80. = =A0Bottom line: =A0I don't subscribe to the idea that changing oil = really often is "cheap insurance" - insurance is only cheap if it = actually insures against something and if the oil hasn't been in there = for more than 6 months or so and still looks good there is really = nothing to be gained by changing it. =A0I feel that any servicing is = often a bigger risk - are all the bolts tight, was there anything left = off, etc.

All just = my opinion,
Gary Casey

On Mar 1, 2008, = at 3:01 AM, Lancair Mailing List wrote:

From: "Douglas Brunner" <douglasbrunner@earthlink.net<= /a>>
To: lml@lancaironline.net
Subject: Oil Temps and Oil = Doors


On a recent trip from Florida to Tennessee I observed oil = temps in the 150s.=A0
=A0
My = engine is an IO-550N built by Monty Barrett.=A0 I decided not to install = a remotely controlled oil door because I had been told that low oil = temps were rarely/never a problem in the Legacy.=A0 My experience = differs.
=A0
When I started the flight OATs = (8000) ft were in the 40s and oil temps were in the 180s.=A0 But by the = time I finished OATs (8000) were in the 20s and oil temps were in the = 150s.=A0 Related to and probably partially the cause of the problem was = my use of a low power setting (2300 RPM, no ram air, 30deg LOP) to = extend range.
=A0
Can low = oil temps shorten TBO/damage the engine?=A0=A0
Even with regular 25 hour=A0oil changes using = Exxon Elite?=A0
Should = I go to the trouble to retrofit a remote oil door, or just change my oil = at a shorter interval?
=A0
Enquiring= minds wish to know.
=A0
D. = Brunner

= --Apple-Mail-31-578982169--