lml@lancaironline.net Mailing List Archive

<x-flowed> <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> << Lancair Builders' Mail List >> <<<<<<<<<<<<<<<<--->>>>>>>>>>>>>>>> >> Ron, First, The purpose of the Cylinder Head Intake Port Drains are to prevent hydrostatic lock and flooding. The excess fuel from priming during starting is vented overboard by the drains. The check or sniffle valve is left to the airframer to install. It is part of a TCM installation audit/checklist with a note that a 2 way check valve(s)is required for turbocharged engines. If it was only a leak it would not be on issue. Pressurized planes use a "calibrated leak" to supply air for cabin pressurization but they are upstream of the throttle and use sonic nozzles to restrict the flow rate. The issue is that the manifold pressure is below ambient when the turbo is not boosting or all the time in naturally aspirated engines. The two major issues presented with not using a check valve on the cylinder head intake port drains are: 1.) Air and dirt are ingested through the open port 2.) Idle speeds are difficult to set with an induction leak TCM uses two different valves 2 way valve for turbocharged application P/N 640197 1 way valve for naturally aspirated P/N 639486 ERic-- Eric, I have a Cont. TSIO-360 FB in my Turbo Dakota. It has a fuel drain lines connected to each intake valve pocket. All 6 are teed together under the engine. I can see no sniffle valve at all. I asked my A&P about this and he said it's a "calibrated leak" and is not supposed to have a valve. Is that correct? It bothers me a bit because the engine spits out a fair amount of fuel from this drain. Seems dangerous and wasteful to me. Ron Laughlin ****************************************** Eric wrote: Date: Fri, 09 Feb 2001 13:26:28 From: "Eric Parlow" <ericparlow@hotmail.com> To: lancair.list@olsusa.com Subject: Re: Sniffle valve on IO-550-N (or G) Message-ID: <F65RlC6aVEpjwGXSXCW0000f677@hotmail.com> Every TCM IO-550-N2B is delivered with a check (sniffle) valve p/n 640197. ERic- _________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> 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. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> </x-flowed>