X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Thu, 29 May 2008 08:02:50 -0400 Message-ID: X-Original-Return-Path: Received: from mta16.adelphia.net ([68.168.78.211] verified) by logan.com (CommuniGate Pro SMTP 5.2.3) with ESMTP id 2943877 for lml@lancaironline.net; Thu, 29 May 2008 07:52:53 -0400 Received-SPF: pass receiver=logan.com; client-ip=68.168.78.211; envelope-from=super_chipmunk@roadrunner.com Received: from Laptop ([74.75.176.139]) by mta16.adelphia.net (InterMail vM.6.01.05.04 201-2131-123-105-20051025) with SMTP id <20080529115151.YYTV10601.mta16.adelphia.net@Laptop> for ; Thu, 29 May 2008 07:51:51 -0400 X-Original-Message-ID: <5723DD6A602044618D7D589F0D92833B@Laptop> From: "Bill Wade" X-Original-To: "Lancair Mailing List" References: In-Reply-To: Subject: Re: [LML] Crankcase pressure=OIL ON BELLY/Photos X-Original-Date: Thu, 29 May 2008 07:52:17 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0097_01C8C160.EA79EF60" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Windows Mail 6.0.6001.18000 X-MimeOLE: Produced By Microsoft MimeOLE V6.0.6001.18000 This is a multi-part message in MIME format. ------=_NextPart_000_0097_01C8C160.EA79EF60 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable 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. 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? Does = the bit of aluminum tape in the upper photo cover a previous routing = hole? 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. 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. 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. How much time on the engine and who built It? My best guesses- Bill Wade ------=_NextPart_000_0097_01C8C160.EA79EF60 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Steve-
         I=20 run an IO-550-B. The installation is FWF from an A-36 Bonanza and though = I=20 didn't do the installation everything was reused that could be. The vent = tubing=20 is aluminum with only short hose sections for = coupling. It runs=20 upward from the filler tube, over the oil cooler and through the = baffling before=20 it turns down and wanders over to the cowl flap. It appears to be above = the=20 filler cap at the highest point. Someone could check me on this but I'd = guess=20 that was the arrangement used by Beech, possibly to counter a problem = like=20 yours. The engine has 2K total time, about 400 hrs since top overhaul, = pressure=20 is 60#. I use 9 quarts (12 qt capacity) and apart from a = slight mist=20 off the front seal it stays squeaky clean. Almost nothing comes out = the=20 vent tube.
 
 From your picture that doesn't = seem to be an=20 option but would it be possible to gain height by going over the #2 = intake or=20 upward aft of the baffle so that any oil might separate and drain = back to=20 the filler? Does the bit of aluminum tape in the upper photo cover = a=20 previous routing hole?
 
 I had also been thinking that you = might have=20 excessive pressure inside your lower cowling. I'm trying to explain = the=20 manometer change at 120KT- perhaps the outlet size is adequate = up to=20 that point but not enough to allow increased flow at higher = speeds. Since=20 your vent tube terminates inside the cowling that might pressurize = the=20 crankcase. I wouldn't expect it to cause oil to blow out the = breather=20 though- it might come from somewhere else if that was the = case.
 
 You have checked for leakage = extensively=20 although initially you were wondering whether there might be leakge = from=20 the alternator etc. From that I guess you had oil all over the rear = of the=20 engine? I notice the vent tube ends quite a bit above the bottom of = the=20 firewall. Air currents inside the cowling can spread oil from even a = small leak=20 all over the place and there's a long way for the vent oil to = exit.
 
 I'd suggest a temporay extension = outside the=20 cowling to see what that might do. The whistle hole should also be = closed off.=20 At the very least that'd eliminate lower cowling pressure as a factor = and any=20 flow from the vent would go straight onto the belly so you'd have a = chance to=20 see if there was leakage from anywhere else. Also, if there's any way=20 to have oil drain back into the filler it might help a = lot.
 
  How much time on the engine and = who built=20 It?
 
  My best guesses-  Bill=20 Wade
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