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View Poll Results: sniffle valve yes or no?
Yes must have a sniffle valve 40 66.67%
sniffle valve is not really needed 20 33.33%
Voters: 60. You may not vote on this poll

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  #21  
Old 02-09-2011, 11:16 AM
Bavafa Bavafa is offline
 
Join Date: Oct 2007
Location: Sacramento, CA
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Quote:
Originally Posted by deene View Post
I have a horizontal sump with a sniffle valve and experience the oil/fuel drips. What I don't understand is where the oil part of the drainage is coming from...seepage from the intake valve guides?
Mine has been doing it since day one and still doing it after 300+ hours. A number of calls to Lycoming gave me unsatisfactory answers but all consensus are that is from the guides and nothing to worry about. It is only a few drops at most.
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  #22  
Old 02-10-2011, 09:24 PM
DENMACRES DENMACRES is offline
 
Join Date: Aug 2008
Location: MONTGOMERY, TX.
Posts: 89
Default snifl valve

I do not use a valve. IO-360 horz. induct. AFP injection/purge valve. I use the port to get MP, This gives a average of all cyls. 850hrs. on engine no problems.
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  #23  
Old 02-11-2011, 07:02 AM
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DanH DanH is offline
 
Join Date: Oct 2005
Location: 08A
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Quote:
Originally Posted by miyu1975 View Post
....I am trying to figure out if my engine already has or needs a sniffle valve. Where would it be located...
Here you go Ryan....AFP sniffle, the blue fitting. Plumb a line to a point just outside the cowl cooling air outlet, or anywhere else allowing liquid to drip to the ground.



Quote:
If the valve is installed, by it's very design, will vent any pressure in the manifold that is in excess of ambient cowl air pressure, degrading manifold pressure recovery when the lower cowl pressure is ambient or slightly below.
Interesting point. As you say, it is a matter of relative pressures. Plumbing the sniffle to the cowl exit should cause it to open and flow air down the drain tube in the special case of excellent dynamic pressure recovery and high IAS. For a SARL guy at 200 knots and 2500 ft, theory says sump pressure would be higher than ambient by 0.8 to 0.85 psi, given the pressure drops reported for better filtered and unfiltered intakes. However, given a large enough intake opening, would it result in any measurable pressure loss to the engine? The supply is unlimited while the leak is limited to flow thorugh a constricted -4 fitting.

Hmmmm...I have a few small Parker solenoid valves....
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