X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from imr-da04.mx.aol.com ([205.188.105.146] verified) by logan.com (CommuniGate Pro SMTP 5.3.9) with ESMTP id 4472518 for flyrotary@lancaironline.net; Sun, 19 Sep 2010 11:10:27 -0400 Received-SPF: pass receiver=logan.com; client-ip=205.188.105.146; envelope-from=Lehanover@aol.com Received: from imo-da01.mx.aol.com (imo-da01.mx.aol.com [205.188.169.199]) by imr-da04.mx.aol.com (8.14.1/8.14.1) with ESMTP id o8JF9eoD009553 for ; Sun, 19 Sep 2010 11:09:40 -0400 Received: from Lehanover@aol.com by imo-da01.mx.aol.com (mail_out_v42.9.) id q.eb3.694c610 (34959) for ; Sun, 19 Sep 2010 11:09:35 -0400 (EDT) Received: from magic-m17.mail.aol.com (magic-m17.mail.aol.com [172.21.147.70]) by cia-da06.mx.aol.com (v129.4) with ESMTP id MAILCIADA068-888f4c9627afc0; Sun, 19 Sep 2010 11:09:35 -0400 From: Lehanover@aol.com Message-ID: <49549.4ed3e70a.39c781af@aol.com> Date: Sun, 19 Sep 2010 11:09:35 EDT Subject: Re: [FlyRotary] Re: Check PSRU Oil Drain-back hose was Re: Watch that psru oi... To: flyrotary@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="part1_49549.4ed3e70a.39c781af_boundary" X-Mailer: 9.0 Security Edition for Windows sub 5381 X-AOL-IP: 173.88.9.178 X-Spam-Flag:NO X-AOL-SENDER: Lehanover@aol.com --part1_49549.4ed3e70a.39c781af_boundary Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit In a message dated 9/19/2010 9:19:17 A.M. Eastern Standard Time, msteitle@gmail.com writes: Ed, You and Lynn may have hit on something regarding the crankcase vent line being too small. It may have been marginally acceptable with the side port engine, but way undersized for the fire-breathing p-port. First time I ran it real hard, out came the seal. I am using the stock vent line, but will go ahead and up-size it while I'm fixing the psru seal. Mark The engine and PSRU are a pressurized system at about the same pressure. The engine is pressurized by blow by combustion gasses leaking past the side seals and oil scrapers. The PRSU is pressurized to the same value through the oil drain-back line. So, drain back would be impeded to some extent until the pressures are equal. After that it would be a constant until a power change is made that increases or decreases blow-by. Since the volume of the PSRU is so small it could be discounted as a drain-back problem, but the same pressure as the crank case will still be present. And that pressure added by the volume of lubricating oil (at 70 PSI or more) for the bearings, though not a large factor when the drain back hose diameter is adequate. Some builders use the factory side seal end play specification, allowing up to .004". I use zero end play in side seals. I install them tight, and then reduce length until the side seals and corner seal will just pop back up after being fully compressed into the rotor. The side seal is being pushed along by only one side of the corner seal. The seal end wears into the corner seal in short order. This starts making clearance right at break in. The direct outcome, is nearly zero blow by. Pressure not lost to blow by, is free HP. This does not apply to Renesis engines where the side seal is exposed to exhaust gas flow and needs extra clearance to survive. (Because it runs hotter and gets longer). Let us say that our engine has normal blow by of 12 cubic feet per minute. The stock breather pipe in the filler tube is smaller than 3/16". This means the gas velocity out of that pipe and into a catch can may be very high. So rich in energy that it can evacuate large amounts of oil droplets in the catch can. So, you make the vent pipe as large as is practical. That same 12 cubic feet, or more, still escapes, but now the crank case pressure is lower (less restriction) and gas velocity is way down. Down on energy and velocity the escaping gasses can no long lift oil droplets and drop them into the catch can. The catch can must have at least 5 times the open vent area of the hose cross section. You can look into the catch can and see how your engine is doing. Nothing in the can? Doing just fine. Some oil in the catch can? Watch engine closely. A couple of inches in the catch can? Put in the spare engine. The stock system of breathing into the intake manifold is fine for partial throttle, freeway speeds where only 25 HP is being used. For constant wide open throttle at about 6,000 RPM, and 160 HP, an adjustment must be made. Why do old Mazdas smoke and use oil? They drink it through the breather hose connected to the intake manifold, as blow by increases with age. Nothing to do the OMP (Oil Metering Pump) at all. The actual crank case pressure is a function of leak rate over vent tube cross section. Lynn E. Hanover --part1_49549.4ed3e70a.39c781af_boundary Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
In a message dated 9/19/2010 9:19:17 A.M. Eastern Standard Time,=20 msteitle@gmail.com writes:
Ed,=20

You and Lynn may have hit on something regarding the crankcase vent= line=20 being too small.  It may have been marginally acceptable with the= side=20 port engine, but way undersized for the fire-breathing p-port.  Fir= st=20 time I ran it real hard, out came the seal.  I am using the stock= vent=20 line, but will go ahead and up-size it while I'm fixing the psru seal.= =20  

Mark
The engine and PSRU are a pressurized system at about the same pressu= re.=20 The engine is pressurized by blow by combustion gasses leaking past the si= de=20 seals and oil scrapers. The PRSU is pressurized to the same value through= the=20 oil drain-back line. So, drain back would be impeded to some extent until= the=20 pressures are equal. After that it would be a constant until a power chang= e is=20 made that increases or decreases blow-by. Since the volume of the PSRU is= so=20 small it could be discounted as a drain-back problem, but the same pressur= e as=20 the crank case will still be present. And that pressure added by the= volume=20 of lubricating oil (at 70 PSI or more) for the bearings, though not a larg= e=20 factor when the drain back hose diameter is adequate. 
 
Some builders use the factory side seal end play specification, allow= ing up=20 to .004". I use zero end play in side seals. I install them tight, and the= n=20 reduce length until the side seals and corner seal will just pop back up= after=20 being fully compressed into the rotor. The side seal is being pushed along= by=20 only one side of the corner seal. The seal end wears into the corner seal= in=20 short order. This starts making clearance right at break in. The direct ou= tcome,=20 is nearly zero blow by. Pressure not lost to blow by, is free HP.
 
This does not apply to Renesis engines where the side seal is exposed= to=20 exhaust gas flow and needs extra clearance to survive. (Because it runs ho= tter=20 and gets longer).
 
Let us say that our engine has normal blow by of 12 cubic feet per mi= nute.=20 The stock breather pipe in the filler tube is smaller than 3/16". This mea= ns the=20 gas velocity out of that pipe and into a catch can may be very high. So ri= ch in=20 energy that it can evacuate large amounts of oil droplets in the catch can= . So,=20 you make the vent pipe as large as is practical. That same 12 cubic feet,= or=20 more, still escapes, but now the crank case pressure is lower (less= =20 restriction) and gas velocity is way down. Down on energy and velocity the= =20 escaping gasses can no long lift oil droplets and drop them into the catch= can.=20 The catch can must have at least 5 times the open vent area of the hose cr= oss=20 section. You can look into the catch can and see how your engine is doing.= =20 Nothing in the can? Doing just fine. Some oil in the catch can? Watch engi= ne=20 closely.
 
A couple of inches in the catch can? Put in the spare engine.
 
The stock system of breathing into the intake manifold is fine for pa= rtial=20 throttle, freeway speeds where only 25 HP is being used. For constant wide= open=20 throttle at about 6,000 RPM, and 160 HP, an adjustment must be made.=
 
Why do old Mazdas smoke and use oil? They drink it through the breath= er=20 hose connected to the intake manifold, as blow by increases with age. Noth= ing to=20 do the OMP (Oil Metering Pump) at all.
 
The actual crank case pressure is a function of leak rate over vent= tube=20 cross section.
 
Lynn E. Hanover
 
 
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