X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Thu, 05 Jun 2008 21:35:42 -0400 Message-ID: X-Original-Return-Path: Received: from n27.bullet.mail.mud.yahoo.com ([68.142.206.222] verified) by logan.com (CommuniGate Pro SMTP 5.2.3) with SMTP id 2954903 for lml@lancaironline.net; Thu, 05 Jun 2008 13:06:56 -0400 Received: from [68.142.194.244] by n27.bullet.mail.mud.yahoo.com with NNFMP; 05 Jun 2008 17:06:00 -0000 Received: from [68.142.201.69] by t2.bullet.mud.yahoo.com with NNFMP; 05 Jun 2008 17:06:44 -0000 Received: from [127.0.0.1] by omp421.mail.mud.yahoo.com with NNFMP; 05 Jun 2008 17:06:44 -0000 X-Yahoo-Newman-Id: 183902.57269.bm@omp421.mail.mud.yahoo.com Received: (qmail 34595 invoked from network); 5 Jun 2008 17:06:43 -0000 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com; h=Received:X-Yahoo-Newman-Property:From:To:References:In-Reply-To:Subject:Date:Message-ID:MIME-Version:Content-Type:X-Mailer:Thread-Index:Content-Language; b=dOPxZtvLAFDXkCHCz0+qOrhNO78Y4maPtUOMYaYD0U9FGK5w9XPb7ezp0e4U+OdEWLHQwB1drt/1r02F6VVSfiKYvU07WN0LvcBgwN0G1G+wmxaKMABjc/lIln406N8QJOORoqqZ6Y1LrbfsnKthZ0uhny3iCMK4XMk8aJGZ9IM= ; Received: from unknown (HELO Laptop) (mcmess1919@207.207.15.34 with login) by smtp101.plus.mail.sp1.yahoo.com with SMTP; 5 Jun 2008 17:06:39 -0000 X-Yahoo-Newman-Property: ymail-3 From: "Steve Colwell" X-Original-To: "'Lancair Mailing List'" References: In-Reply-To: Subject: Crankcase pressure=OIL ON BELLY/Photos X-Original-Date: Thu, 5 Jun 2008 12:06:37 -0500 X-Original-Message-ID: <000001c8c72e$86d18440$94748cc0$@com> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0001_01C8C704.9DFB7C40" X-Mailer: Microsoft Office Outlook 12.0 Thread-Index: AcjBg+zuTBYWn+4PRg2L96X4JIPaGgFGFcig Content-Language: en-us This is a multipart message in MIME format. ------=_NextPart_000_0001_01C8C704.9DFB7C40 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Bill, =20 Thanks for the ideas, I have been doing some further = testing=85=85=85=85=85.. =20 From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of = Bill Wade =20 Steve- I run an IO-550-B. The installation is FWF from an A-36 Bonanza = and though I didn't do the installation everything was reused that could be. = The vent tubing is aluminum with only short hose sections for coupling. It = runs upward from the filler tube, over the oil cooler and through the = baffling before it turns down and wanders over to the cowl flap. It appears to be above the filler cap at the highest point. Someone could check me on = this but I'd guess that was the arrangement used by Beech, possibly to = counter a problem like yours. The engine has 2K total time, about 400 hrs since = top overhaul, pressure is 60#. I use 9 quarts (12 qt capacity) and apart = from a slight mist off the front seal it stays squeaky clean. Almost nothing = comes out the vent tube. If you have a Legacy, can you give me a measurement = of the exit end of your crankcase breather? The easiest reference could be = the lower left motor mount hole in the firewall. How much higher? How far = to the right? =20 From your picture that doesn't seem to be an option but would it be possible to gain height by going over the #2 intake or upward aft of the baffle so that any oil might separate and drain back to the filler? I = have not tried to get the vent tube higher since the exit from the dipstick housing is fairly high and the top of the cowl would not allow me to get more than =BD=94 or so higher. =20 =20 Does the bit of aluminum tape in the upper photo cover a previous = routing hole? The tape covers a =93Anti-siphon hole=94 I added after the = problem began at the suggestion of ECI the cylinder manufacturer. It was taped off in = the photo for a test and has been tried open and closed in several tests. =20 I had also been thinking that you might have excessive pressure inside = your lower cowling. I'm trying to explain the manometer change at 120KT- = perhaps the outlet size is adequate up to that point but not enough to allow increased flow at higher speeds. Since your vent tube terminates inside = the cowling that might pressurize the crankcase. I wouldn't expect it to = cause oil to blow out the breather though- it might come from somewhere else = if that was the case. I finally have a glimmer of hope. I relocated the crankcase vent exit about 2=94 above the original location and 3/4=94 = further from the centerline of the cowl exit. In a quick trip around the = pattern the belly had only a thin film of oil rather than a thick coat. The suggestion from a friend (who managed the service dept. for the Cessna dealer in Sacramento) was to move the vent exit away from the low = pressure area caused by venturi effect at the cowl exit. I measured the pressure difference between the original location and the most recent one with a = 2=94 increase on the manometer. =20 You have checked for leakage extensively although initially you were wondering whether there might be leakge from the alternator etc. From = that I guess you had oil all over the rear of the engine? I notice the vent = tube ends quite a bit above the bottom of the firewall. Air currents inside = the cowling can spread oil from even a small leak all over the place and = there's a long way for the vent oil to exit. Early on, I washed the engine down with solvent to check the source of the leak, it is all coming from the breather. =20 =20 I'd suggest a temporay extension outside the cowling to see what that = might do. The whistle hole should also be closed off. At the very least that'd eliminate lower cowling pressure as a factor and any flow from the vent would go straight onto the belly so you'd have a chance to see if there = was leakage from anywhere else. Also, if there's any way to have oil drain = back into the filler it might help a lot. I removed a Andair Air/Oil = Separator for testing to keep it from masking the results. The plan is to put it = back in the system to minimize oil loss when I am sure what is going on. =20 How much time on the engine and who built It? It is a Performance = Engine with about 50 hours, stock 9:1 compression and magnetos, Ron Monson has = been very helpful. =20 My best guesses- Bill Wade Mine too-Steve Colwell __________ NOD32 3142 (20080528) Information __________ This message was checked by NOD32 antivirus system. http://www.eset.com ------=_NextPart_000_0001_01C8C704.9DFB7C40 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

Bill,

 

Thanks for the ideas, I have been doing some further = testing……………..

 

From:= Lancair = Mailing List [mailto:lml@lancaironline.net] On Behalf Of Bill Wade

 

Steve-=

  &= nbsp;      I run an IO-550-B. The installation is FWF from an A-36 Bonanza and = though I didn't do the installation everything was reused that could be. The vent tubing = is aluminum with only short hose sections for coupling. It = runs upward from the filler tube, over the oil cooler and through the = baffling before it turns down and wanders over to the cowl flap. It appears to be = above the filler cap at the highest point. Someone could check me on this but = I'd guess that was the arrangement used by Beech, possibly to counter a = problem like yours. The engine has 2K total time, about 400 hrs since top = overhaul, pressure is 60#. I use 9 quarts (12 qt capacity) and apart = from a slight mist off the front seal it stays squeaky clean. Almost = nothing comes out the vent tube. = If you have a = Legacy, can you give me a measurement of the exit end of your crankcase breather?=A0 = The easiest reference could be the lower left motor mount hole in the = firewall.=A0 How much higher?=A0 How far to the right?

 

 From your picture that doesn't seem to be an option but would it be possible = to gain height by going over the #2 intake or upward aft of the baffle so = that any oil might separate and drain back to the filler? I have not = tried to get the vent tube higher since the exit from the dipstick housing is = fairly high and the top of the cowl would not allow me to get more than = =BD” or so higher.=A0

=A0

Does the bit of aluminum tape in the upper photo cover a previous = routing hole?=A0 The tape covers a “Anti-siphon hole” I added = after the problem began at the suggestion of ECI the cylinder manufacturer.=A0 = It was taped off in the photo for a test and has been tried open and closed in = several tests.

 

 I had also been thinking that you might have excessive pressure inside = your lower cowling. I'm trying to explain the manometer change at 120KT- perhaps the outlet size is adequate up to that point but not = enough to allow increased flow at higher speeds. Since your vent tube = terminates inside the cowling that might pressurize the crankcase. I = wouldn't expect it to cause oil to blow out the breather though- it might come = from somewhere else if that was the case.=A0 = I finally have a glimmer of hope.  I relocated the crankcase vent = exit about 2” above the original location and 3/4” further from the = centerline of the cowl exit.  In a quick trip around the pattern the belly had = only a thin film of oil rather than a thick coat.  The suggestion from a = friend (who managed the service dept. for the Cessna dealer in Sacramento) was = to move the vent exit away from the low pressure area caused by venturi effect = at the cowl exit.  I measured the pressure difference between the original location and the most recent one with a 2”  increase on the manometer.

 

 You have checked for leakage extensively although initially you = were wondering whether there might be leakge from the alternator etc. From that I = guess you had oil all over the rear of the engine? I notice the vent tube ends quite a bit above the bottom of the firewall. = Air currents inside the cowling can spread oil from even a small leak all = over the place and there's a long way for the vent oil to exit.=A0 Early on, I = washed the engine down with solvent to check the source of the leak, it is all coming from = the breather.

 

 

 I'd suggest a temporay extension outside the cowling to see what that might = do. The whistle hole should also be closed off. At the very least that'd = eliminate lower cowling pressure as a factor and any flow from the vent would go = straight onto the belly so you'd have a chance to see if there was leakage from = anywhere else. Also, if there's any way to have oil drain back into the = filler it might help a lot.=A0 I removed a = Andair Air/Oil Separator for testing to keep it from masking the results.=A0 = The plan is to put it back in the system to minimize oil loss when I am sure what is = going on.

 

  How much time on the engine and who built It?=A0 It is a = Performance Engine with about 50 hours, stock 9:1 compression and magnetos, Ron = Monson has been very helpful.

 

  My best guesses-  Bill Wade

Mine too-Steve Colwell



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