X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml Date: Sat, 15 Jul 2006 13:51:22 -0400 Message-ID: X-Original-Return-Path: Received: from [66.83.119.58] (HELO lucky.dts.local) by logan.com (CommuniGate Pro SMTP 5.1c.2) with ESMTP id 1238199 for lml@lancaironline.net; Sat, 15 Jul 2006 13:37:40 -0400 Received-SPF: none receiver=logan.com; client-ip=66.83.119.58; envelope-from=cjensen@dts9000.com X-MimeOLE: Produced By Microsoft Exchange V6.5.6944.0 Content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----_=_NextPart_001_01C6A835.838DA40E" Subject: RE: [LML] Lancair 4p overheating X-Original-Date: Sat, 15 Jul 2006 13:38:42 -0400 X-Original-Message-ID: <8984A39879F2F5418251CBEEC9C689B31DA1E6@lucky.dts.local> X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: [LML] Lancair 4p overheating Thread-Index: AcaoIgTPk/rY6zeOSa6H/MU8EXoYPAAEhm8w From: "Chuck Jensen" X-Original-To: "Lancair Mailing List" This is a multi-part message in MIME format. ------_=_NextPart_001_01C6A835.838DA40E Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Jim, =20 With all due respect, did you mean to say that you 'now only run ROP because of too high EGT's when LOP'? I'm neither an engine expert nor a sleeper at Holiday inn, but EGTs are indicators of nothing, other than as the mixture is leaned out, the EGT will continue to rise until you go lean of peak, at which point, it starts descending on the other side of the mixture curve. Perhaps it's a play on words or imprecise use of words, but you will have the same EGTs on both sides of the mixture curve. By definition, if fuel injectors for your cylinders are properly balanced, you can not have high EGTs LOP. LOP ops indicate that you have gone past the peak EGTs. The same as your speed well be 50 mph twice when making a trip at 70 mph (the peak speed)...once as you speed up to 70 (peak EGT) and once on the way down (LOP). =20 ROP operations, at least for Lycomings, will result in higher fuel consumption, higher peak cylinder pressures, higher CHT and potentially accelerated valve degradation. Of course, LOP operations assumes 1) use of injectors, 2) the injectors have been properly balanced, 3) that you have EIS information that allows you to track each cylinder. =20 =20 You may wish to research the GAMI website, Air Performance website and other sources regarding the relatively merits of ROP and LOP operations. Then again, perhaps our specific engine is different, in which case, forget everything I just wrote. =20 Chuck Jensen =20 =20 -----Original Message----- From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of JIMRHER@aol.com Sent: Saturday, July 15, 2006 11:17 AM To: Lancair Mailing List Subject: [LML] Lancair 4p overheating =20 Jeff asked; =20 From: "Jeff Gregory" Sender: Subject: Lancair 4p overheating Date: Fri, 14 Jul 2006 13:32:50 -0400 To: lml =20 =20 We have been having problems with our cht. Last saturday we were cruising at 11000' and at 28" and 2500rpm our cht was rising to almost 400 degrees. It seems like we all of a sudden started having high cht for no reason. Have you noticed this with any other 4p's. Jeff=20 =20 Jeff, I have had a similar experience. I have over 400 hrs on my 4P and one time I was flying for over 1.5 hrs level at altitude running LOP and within about 1 min. I had number 3 CHT just start marching up to 420* where I had my alarm set. I went full rich for a while until all temps were back to my normal high and then continue back to LOP. I never saw that situation again. =20 For the record, I now only run ROP because of too high EGT's when LOP and I have replaced two complete sets of cylinders in my 400 hrs all with exhaust valve stems and guides warn beyond service limits. Jim ------_=_NextPart_001_01C6A835.838DA40E Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Jim,

 

With all due respect, did you mean = to say that you ‘now only run ROP because of too high EGT's when = LOP’?  I’m neither an engine expert nor a sleeper at Holiday inn, but EGTs = are indicators of nothing, other than as the mixture is leaned out, the EGT = will continue to rise until you go lean of peak, at which point, it starts descending on the other side of the mixture curve.  Perhaps = it’s a play on words or imprecise use of words, but you will have the same EGTs on = both sides of the mixture curve.  By definition, if fuel injectors for = your cylinders are properly balanced, you can not have high EGTs LOP.  LOP ops = indicate that you have gone past the peak EGTs. The same as your speed well be 50 = mph twice when making a trip at 70 mph (the peak speed)…once as you speed up = to 70 (peak EGT) and once on the way down (LOP).

 

ROP operations, at least for = Lycomings, will result in higher fuel consumption, higher peak cylinder pressures, = higher CHT and potentially accelerated valve degradation.  Of course, LOP operations assumes 1) use of injectors, 2) the injectors have been = properly balanced, 3) that you have EIS information that allows you to track each cylinder. 

 

You may wish to research the GAMI = website, Air Performance website and other sources regarding the relatively = merits of ROP and LOP operations.  Then again, perhaps our specific engine is = different, in which case, forget everything I just wrote.

 

Chuck Jensen

 

 

-----Original Message-----
From: Lancair Mailing = List [mailto:lml@lancaironline.net] On = Behalf Of JIMRHER@aol.com
Sent: Saturday, July 15, 2006 11:17 = AM
To: Lancair Mailing = List
Subject: [LML] Lancair 4p overheating

 

Jeff asked;

 

From:

"Jeff Gregory" <jeffgregory@bellsouth.net>

Sender:

=

<marv@lancaironline.net>

Subject:

Lancair 4p = overheating

Date:

Fri, 14 Jul 2006 13:32:50 = -0400

To:

lml


=

We have been having problems with our cht.  = Last saturday we were cruising at 11000' and at 28" and 2500rpm our = cht was rising to almost 400 degrees.  It seems like we all of a sudden = started having high cht for no reason. Have you noticed this with any other = 4p's.

Jeff

 

Jeff, I have had a similar experience. I have over 400 hrs on my 4P and one = time I was flying for over 1.5 hrs level at altitude running LOP and within = about 1 min. I had number 3 CHT just start marching up to 420* where I had my = alarm set. I went full rich for a while until all temps were back to my normal = high and then continue back to LOP. I never saw that situation = again.

 

For the record, I now only run ROP because of too high EGT's when LOP and I = have replaced two complete sets of cylinders in my 400 hrs all with exhaust = valve stems and guides warn beyond service limits.

Jim

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