Return-Path: Received: from pop3.olsusa.com ([63.150.212.2] verified) by logan.com (CommuniGate Pro SMTP 3.4.5) with ESMTP id 774556 for rob@logan.com; Sun, 06 May 2001 15:49:33 -0400 Received: from blount.mail.mindspring.net ([207.69.200.226]) by pop3.olsusa.com (Post.Office MTA v3.5.3 release 223 ID# 0-71175U5500L550S0V35) with ESMTP id com for ; Sun, 6 May 2001 08:31:53 -0400 Received: from edechazalmindspring (user-2injl2n.dialup.mindspring.com [165.121.212.87]) by blount.mail.mindspring.net (8.9.3/8.8.5) with SMTP id IAA07431 for ; Sun, 6 May 2001 08:38:36 -0400 (EDT) Message-ID: <000601c0d621$122edda0$57d479a5@com> From: "Ed de Chazal" To: References: <20010506040511.AAA10731@pop3.olsusa.com> Subject: Re: LOP vs ROP Date: Sun, 6 May 2001 07:38:27 -0400 MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit X-Mailing-List: lancair.list@olsusa.com Reply-To: lancair.list@olsusa.com <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> << Lancair Builders' Mail List >> <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> >> Hi Jon, I saw your question back to George about the cause of the LOP roughness. The answer is that the forces on the crank are different between cylinders due to mixture variation as the charts imply. At a constant rpm, the engine vibration due to rotational imbalances don't change regardless of power settings and the combustion pressure is obviously uniform throughout the cylinder once the flame front has progressed through the charge (happens very quickly for our purposes). To test this explanation, consider the extreme case of roughness being when one cylinder doesn't fire say due to a fouled plug. That pushes the variation in force on the crank to the maximum and you can imagine how that feels. George, after reading your description of "the big pull", I'm still wondering if the "forbidden zone" of mixture isn't just a relative issue. Some guys on this list are reporting excellent cylinder cooling and claim CHTs below 350 degrees in cruise (what mixture settings, I don't know). If CHTs are low at 50 degrees ROP, isn't everything OK except that they would be be better at 50 degrees LOP? Like Jon, I'm looking to make sure I understand the relationships properly here. Ed de Chazal Rochester Michigan >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> LML website: http://www.olsusa.com/Users/Mkaye/maillist.html LML Builders' Bookstore: http://www.buildersbooks.com/lancair Please send your photos and drawings to marvkaye@olsusa.com. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>