X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sat, 07 Jun 2008 15:09:45 -0400 Message-ID: X-Original-Return-Path: Received: from mta10.adelphia.net ([68.168.78.202] verified) by logan.com (CommuniGate Pro SMTP 5.2.3) with ESMTP id 2957466 for lml@lancaironline.net; Sat, 07 Jun 2008 08:35:04 -0400 Received-SPF: pass receiver=logan.com; client-ip=68.168.78.202; envelope-from=glcasey@adelphia.net Received: from [76.166.22.191] by mta10.adelphia.net (InterMail vM.6.01.05.02 201-2131-123-102-20050715) with ESMTP id <20080607123637.TMHT20419.mta10.adelphia.net@[76.166.22.191]> for ; Sat, 7 Jun 2008 08:36:37 -0400 Mime-Version: 1.0 (Apple Message framework v753) In-Reply-To: References: Content-Type: multipart/alternative; boundary=Apple-Mail-49-459144685 X-Original-Message-Id: <0C94299A-972A-4BB4-AC5D-E7DD83F0BE0C@adelphia.net> From: Gary Casey Subject: Re: Crankcase pressure=OIL ON BELLY/Photo X-Original-Date: Sat, 7 Jun 2008 05:34:22 -0700 X-Original-To: "Lancair Mailing List" X-Mailer: Apple Mail (2.753) --Apple-Mail-49-459144685 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=WINDOWS-1252; delsp=yes; format=flowed This is an age-old subject, but I see that a lot of speculation is =20 going on about "back pressure" in the crankcase being an issue - I =20 don't think that is the place to look. I don't think the location of =20= the vent discharge as it relates to the pressure (or "suction") =20 exerted has any effect. The blowby flow rate is created by the =20 leakage across the rings from the hundreds of psi of combustion =20 pressure so a few inches of water change in pressure won't have any =20 significant effect on flow rate. I think the biggest effect on oil =20 entrainment is the internal engine design and we can't change that. =20 The next closest part to the engine is the vent hose as it comes out =20 and I think that should have an up slope and be as large as possible =20 to keep the velocity of the gases down, allowing oil to drop out and =20 run back down into the engine. After the tube turns back downhill =20 there is nothing you can do, as the oil will run downhill =20 regardless. Rerouting might change how much of the oil is deposited =20 on the belly, but it won't change to total quantity. I'm trying to =20 figure out some sort of aerodynamic separator to keep the oil away, =20 but I'm not sure there is such a thing - too much turbulence down =20 there. And do oil separators work? I have no experience, but the on-=20= line comments range all the way from "perfect" to "not at all". Gary Casey > > From: Steve Colwell > To: lml@lancaironline.net > Sent: Thursday, June 05, 2008 9:35 PM > Subject: [LML] Crankcase pressure=3DOIL ON BELLY/Photos > > Bill, > > > > Thanks for the ideas, I have been doing some further testing=85=85=85=85= =85.. > > --Apple-Mail-49-459144685 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=WINDOWS-1252 This is an age-old subject, but I see that a lot of speculation is going = on about "back pressure" in the crankcase being an issue - I don't think = that is the place to look. =A0I don't think the location of the vent = discharge as it relates to the pressure (or "suction") exerted has any = effect. =A0The blowby flow rate is created by the leakage across the = rings from the hundreds of psi of combustion pressure so a few inches of = water change in pressure won't have any significant effect on flow rate. = =A0I think the biggest effect on oil entrainment is the internal engine = design and we can't change that. =A0The next closest part to the engine = is the vent hose as it comes out and I think that should have an up = slope and be as large as possible to keep the velocity of the gases = down, allowing oil to drop out and run back down into the engine. =A0After= the tube turns back downhill there is nothing you can do, as the oil = will run downhill regardless. =A0Rerouting might change how much of the = oil is deposited on the belly, but it won't change to total quantity. = =A0I'm trying to figure out some sort of aerodynamic separator to keep = the oil away, but I'm not sure there is such a thing - too much = turbulence down there. =A0And do oil separators work? =A0I have no = experience, but the on-line comments range all the way from "perfect" to = "not at all".

Gary Casey

 =
Sent: Thursday, June 05, 2008 = 9:35 PM
Subject: [LML] = Crankcase pressure=3DOIL ON BELLY/Photos

Bill,

=A0

Thanks for the ideas, I have been = doing some further testing=85=85=85=85=85..


= --Apple-Mail-49-459144685--