Return-Path: Received: from pimout7-int.prodigy.net ([207.115.63.106]) by ns1.olsusa.com (Post.Office MTA v3.5.3 release 223 ID# 0-64832U3500L350S0V35) with ESMTP id com for ; Sun, 19 Mar 2000 02:30:04 -0500 Received: from bill (PANGB102-46.splitrock.net [209.253.80.46]) by pimout7-int.prodigy.net (8.8.5/8.8.5) with SMTP id CAA243034 for ; Sun, 19 Mar 2000 02:27:09 -0500 Message-ID: <001001bf9174$8df2d9c0$2e50fdd1@bill> From: "William T Bartlett" To: References: <20000319051233.AAA10182@ns1.olsusa.com> Subject: Thermostatic Bypass Valves in Lycoming Engines Date: Sat, 18 Mar 2000 23:27:11 -0800 Mime-Version: 1.0 X-Mailing-List: lancair.list@olsusa.com <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> << Lancair Builders' Mail List >> <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> >> Bob: The information, you gave us from Lycoming, is of course absolutely right. The conclusion you derived from that information is absolutely wrong. The problem is that if the oil does not reach 180deg F the valve does not close to force the oil through the cooler, but the oil can still go through the cooler. On most engines enough oil enough oil will go through the cooler, so that the oil will never reach operating temp, if the ambient temperature is below about -5degC. Now an engine with a worn thermostatic valve might cause overheating (there are service bulletins about that), but never overcooling. The pressure relieve valve only opens, to bypass the oil cooler, when the oil is very thick, so that the seams of the oil cooler won't blow. The oil cooler isn't as strong as the lines or oil galleries in the case. I guess that if the oil, in the cooler, were so thick that it wouldn't flow you wouldn't have the overcooling problem. Bill N7WB >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> LML website: http://www.olsusa.com/Users/Mkaye/maillist.html Builders' Bookstore: http://www.buildersbooks.com/lancair Please send your photos and drawings to marvkaye@olsusa.com. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>