Return-Path: Sender: (Marvin Kaye) To: lml@lancaironline.net Date: Mon, 15 Mar 2004 11:28:36 -0500 Message-ID: X-Original-Return-Path: Received: from imo-m15.mx.aol.com ([64.12.138.205] verified) by logan.com (CommuniGate Pro SMTP 4.1.8) with ESMTP id 3079741 for lml@lancaironline.net; Mon, 15 Mar 2004 11:16:50 -0500 Received: from Tubamanflies@aol.com by imo-m15.mx.aol.com (mail_out_v37.4.) id q.142.2462e673 (2519) for ; Mon, 15 Mar 2004 11:16:48 -0500 (EST) From: Tubamanflies@aol.com X-Original-Message-ID: <142.2462e673.2d8730f0@aol.com> X-Original-Date: Mon, 15 Mar 2004 11:16:48 EST Subject: Re: [LML] Re: Hot Start Technique THE WAY THAT WORKED X-Original-To: lml@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="part1_142.2462e673.2d8730f0_boundary" X-Mailer: 8.0 for Windows sub 6024 --part1_142.2462e673.2d8730f0_boundary Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Responses: George Shattuck: I think what is going on in your case is that you are cranking until the fuel pressure comes up to give the system the correct mixture. Then the engine will fire. The open throttle is probably not improtant because the airflow is determined by cranking speed on start. But it works so it is the right way to do it. Bob Smiley: I have thought about adding the purge valve but decided to see if I could come up with a technique that would give consistant results. It looks like what I have come up with will work but time will tell. It is an ace in the hole if I need it but it will add complexity. Gary Casey: Again I think the amount of air that the engine gets on start is a function of cranking speed and very little on throttle position as long as it is open a little bit. Just watch the manifold pressure when you crank. Mine hardly changes at all until the engine fires. Without fuel pressure I don't think you will get a start. If your system holds pressure on shudown you will get an easier start. If not you have to crank longer until the vapor is gone and you have liquid fuel. My boost pump is on the firewall and gets heat soaked also. It will not pump fuel vapors. The engine pump will and will bring fuel in until the pressure builds and things cool down. The boost pump will then help but I usally don't even use it on hot starts. Scott Krueger: If I was flying behind the engine in my Honda Civic there would be no problem. Return lines give cool fuel and pumps like to pump cool (liquid) rather than hot (vapor). Some boost pumps like mine will not pump vapor. Fuel pressure equals start, and because it is an experimental you have to experment to see what works best. There are no 2 Lancairs that are the same. The engine driven diaphram pump will always pump, it is a positive displacement pump. If it gets hot enough you will start pumping vapor and loose fuel pressure. It will still pump the vapor but the engine will not run without the right mixtue. Thanks again to all for the great discussion. Ray --part1_142.2462e673.2d8730f0_boundary Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable Responses:

George Shattuck:  I think what is going on in your case is that you are= cranking until the fuel pressure comes up to give the system the correct mi= xture.  Then the engine will fire.  The open throttle is probably=20= not improtant because the airflow is determined by cranking speed on start.&= nbsp;  But it works so it is the right way to do it.

Bob Smiley: I have thought about adding the purge valve but decided to see i= f I could come up with a technique that would give consistant results. = It looks like what I have come up with will work but time will tell. =20= It is an ace in the hole if I need it but it will add complexity.

Gary Casey: Again I think the amount of air that the engine gets on start is= a function of cranking speed and very little on throttle position as long a= s it is open a little bit.  Just watch the manifold pressure when you c= rank.  Mine hardly changes at all until the engine fires.  Without= fuel pressure I don't think you will get a start. If your system holds pres= sure on shudown you will get an easier start.  If not you have to crank= longer until the vapor is gone and you have liquid fuel.  My boost pum= p is on the firewall and gets heat soaked also.  It will not pump fuel=20= vapors.  The engine pump will and will bring fuel in until the pressure= builds and things cool down.  The boost pump will then help but I usal= ly don't even use it on hot starts.

Scott Krueger:  If I was flying behind the engine in my Honda Civic the= re would be no problem.  Return lines give cool fuel and pumps like to=20= pump cool (liquid) rather than hot (vapor).  Some boost pumps like mine= will not pump vapor.   Fuel pressure equals start, and because it= is an experimental you have to experment to see what works best.  Ther= e are no 2 Lancairs that are the same.  The engine driven diaphram pump= will always pump,  it is a positive displacement pump.  If it get= s hot enough you will start pumping vapor and loose fuel pressure.  It=20= will still pump the vapor but the engine will not run without the right mixt= ue.  

Thanks again to all for the great discussion.

Ray --part1_142.2462e673.2d8730f0_boundary--