X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Tue, 03 Feb 2009 16:33:36 -0500 Message-ID: X-Original-Return-Path: Received: from [66.64.141.200] (HELO lucky.dts.local) by logan.com (CommuniGate Pro SMTP 5.2.12) with ESMTP id 3474964 for lml@lancaironline.net; Tue, 03 Feb 2009 16:20:54 -0500 Received-SPF: none receiver=logan.com; client-ip=66.64.141.200; envelope-from=cjensen@dts9000.com Content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----_=_NextPart_001_01C98645.D117AD28" Subject: RE: [LML] Re: cylinder wear-to lean or not too lean X-MimeOLE: Produced By Microsoft Exchange V6.5 X-Original-Date: Tue, 3 Feb 2009 16:24:37 -0500 X-Original-Message-ID: <8984A39879F2F5418251CBEEC9C689B3E86792@lucky.dts.local> In-Reply-To: X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: [LML] Re: cylinder wear-to lean or not too lean Thread-Index: AcmGQpPavhslSOrDRf2fFoGWc/9r7wAAsYrg From: "Chuck Jensen" X-Original-To: "Lancair Mailing List" This is a multi-part message in MIME format. ------_=_NextPart_001_01C98645.D117AD28 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable EGT reading means (almost) nothing. They are neither too high or two = low, since the absolute temperature reading is highly variable depending = on probe location. =20 =20 The only use for the EGT (but it's an important one) is to know where, = as you lean out the engine, your peak EGT is reached. Then you are able = to decide whether to run 75 degrees ROP or 50 degrees LOP. It doesn't = matter if it is 50 degrees lean of 1550F, 1475F, 1400F or any other = number. =20 =20 In short, the absolute value of the EGT reading is not of great = interest....only the trend of the EGT as you lean out the engine. =20 Chuck=20 -----Original Message----- From: Lancair Mailing List [mailto:lml@lancaironline.net]On Behalf Of = Sky2high@aol.com Sent: Tuesday, February 03, 2009 3:57 PM To: lml@lancaironline.net Subject: [LML] Re: cylinder wear-to lean or not too lean Gerard, =20 Not enough information for a really good answer. What are your peak = EGTs? Have you tried to run a GAMI Lean Test ( = http://gami.com/gamijectors/leantest.php) even though it may not be = useful for a carbureted engine? At least study the concepts. =20 My EGT probes are about 4" downstream of the exhaust and I peak at about = 1450. 31 to 32 l/hr is about 8.2 to 8.45 gph. At cruise at 4500' MSL = 2480 rpm and 25" MAP I burn about 10.6 gph and the EGTs are about = 130-140 degrees Rich Of Peak. This is best power for the rpm/map = parameters. Of course, I am injected. =20 It is very difficult to control the power in each cylinder in a = carbureted engine since the throttle position may actually change the = A/F ratio to each cylinder. Perhaps you have recorded cruise parameters = and those might help with the analysis. =20 Generally, your EGTs seem to be too high and if running rich of peak, = you are in a very bad place to be running that engine. =20 Scott Krueger AKA Grayhawk Lancair N92EX IO320 SB 89/96 Aurora, IL (KARR) In a message dated 2/2/2009 11:13:00 A.M. Central Standard Time, = gerardoconnell@optusnet.com.au writes: just burnt out the exhaust valves on 1 and 3 (got 900 hours on my 0-320) the shop reckons I'm running it too lean. I had an EDM 700 installed = last year and follow the directions for best power-usually gives EGT = 1450-1500 and 31-32 Litres per hour what say y'all Gerard >=20 -- For archives and unsub = http://mail.lancaironline.net:81/lists/lml/List.html =20 _____ =20 Great = Deals on Dell = Laptops. Starting at $499.=20 ------_=_NextPart_001_01C98645.D117AD28 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
EGT reading means (almost) = nothing. =20 They are neither too high or two low, since the absolute temperature = reading is=20 highly variable depending on probe location. 
 
The only use for the EGT (but it's = an=20 important one) is to know where, as you lean out the engine, your peak = EGT is=20 reached.  Then you are able to decide whether to run 75 degrees ROP = or 50=20 degrees LOP.    It doesn't matter if it is 50 degrees = lean of=20 1550F, 1475F, 1400F or any other number. 
 
In short, the absolute value of = the EGT=20 reading is not of great interest....only the trend of the EGT as you = lean out=20 the engine. 

Chuck

-----Original Message-----
From: Lancair Mailing = List=20 [mailto:lml@lancaironline.net]On Behalf Of=20 Sky2high@aol.com
Sent: Tuesday, February 03, 2009 3:57=20 PM
To: lml@lancaironline.net
Subject: [LML] Re: = cylinder=20 wear-to lean or not too lean

Gerard,
 
Not enough information for a really good answer.  What are = your peak=20 EGTs?  Have you tried to run a GAMI Lean Test (http://gami.com/gamijec= tors/leantest.php)=20 even though it may not be useful for a carbureted engine?  At = least study=20 the concepts.
 
My EGT probes are about 4" downstream of the exhaust and I peak = at about=20 1450.  31 to 32 l/hr is about 8.2  to 8.45 gph.  At = cruise at=20 4500' MSL 2480 rpm and 25" MAP I burn about 10.6 gph and the EGTs are = about=20 130-140 degrees Rich Of Peak.  This is best power for the rpm/map = parameters.  Of course, I am injected.
 
It is very difficult to control the power in each cylinder in a=20 carbureted engine since the throttle position may actually change the = A/F=20 ratio to each cylinder.  Perhaps you have recorded cruise = parameters and=20 those might help with the analysis.
 
Generally, your EGTs seem to be too high and if running rich of = peak, you=20 are in a very bad place to be running that engine.
 
Scott=20 Krueger AKA Grayhawk
Lancair N92EX IO320 SB 89/96
Aurora, IL=20 (KARR)

In a message dated 2/2/2009 11:13:00 A.M. Central = Standard Time, gerardoconnell@optusnet.com.au writes:


just burnt out the exhaust valves on 1 and 3 (got = 900 hours=20 on my 0-320)

the shop reckons I'm running it too lean. I had = an EDM=20 700 installed last year and follow the directions for best = power-usually=20 gives EGT 1450-1500 and 31-32 Litres per hour

what say=20 y'all

Gerard

>

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For archives and unsub = http://mail.lancaironline.net:81/lists/lml/List.html
 

Great=20 Deals on Dell Laptops. Starting at $499.
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