Return-Path: <lancair.list-request@olsusa.com>
Received: from hotmail.com ([216.33.241.164]) by ns1.olsusa.com
          (Post.Office MTA v3.5.3 release 223 ID# 0-70783U4500L450S0V35)
          with ESMTP id com for <lancair.list@olsusa.com>;
          Tue, 13 Feb 2001 14:25:37 -0500
Received: from mail pickup service by hotmail.com with Microsoft SMTPSVC;
	 Tue, 13 Feb 2001 11:34:18 -0800
Received: from 63.67.151.2 by lw8fd.law8.hotmail.msn.com with HTTP;	Tue, 13 Feb 2001 19:34:18 GMT
From: "Eric Parlow" <ericparlow@hotmail.com>
To: ronlaughlin@hotmail.com
Cc: lancair.list@olsusa.com
Subject: Re: Sniffle Valve
Date: Tue, 13 Feb 2001 19:34:18 
Message-ID: <F164FRaqbC8wSA1XvpF0000b343@hotmail.com>
X-Mailing-List: lancair.list@olsusa.com
Reply-To: lancair.list@olsusa.com
Mime-Version: 1.0

<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>