REFLECTOR: Engine backfiring

Wed Aug 16 11:03:18 CDT 2006

To: Riffle,sniffle and whiffle

Sniffle has to do with inhaling , not exhaling. I don't know what riffle 
means unless you'r shuffeling cards .  Whiffle is a real word that means 
blowing in puffs which would fit its function.

Larry Coen
N135LC

----- Original Message ----- 
From: "John Tvedte" <JohnT at comp-sol.com>
To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
Sent: Wednesday, August 16, 2006 10:11 AM
Subject: Re: REFLECTOR: Engine backfiring

> Ok - I thought it was called a sniffle valve?
>
> John
>
> -----Original Message----- 
> From: reflector-bounces at tvbf.org on behalf of Scott Derrick
> Sent: Wed 8/16/2006 9:42 AM
> To: Velocity Aircraft Owners and Builders list
> Cc:
> Subject: Re: REFLECTOR: Engine backfiring
>
>
> I thought it was called a whiffle valve?
>
> Dave Dent wrote:
>
> Your right I have seen this before.  Some call it the riffle valve. 
> Manifold
> drain valve.  I have encountered this valve missing and one time causing a
> fire.  The fuel didn't drain out and it back fired and lit off.
> Good Call Andy
> Dave
> ----- Original Message ----- 
> From: "Andrew Ellzey" <ajlz72756 at yahoo.com> <mailto:ajlz72756 at yahoo.com>
> To: <velocity at davebiz.com> <mailto:velocity at davebiz.com> ; "Velocity 
> Aircraft Owners and Builders list"
> <reflector at tvbf.org> <mailto:reflector at tvbf.org>
> Sent: Tuesday, August 15, 2006 9:44 PM
> Subject: Re: REFLECTOR: Engine backfiring
>
>
>
>
> Dave,
>
> I had a Mooney M20E that had this engine and flew it for 15 years and
> about
> 600 hours. This engine is known for this problem. The first thing I would
> look at is; there is a 45 degree AN fitting on the bottom of your engine
> that is supposed to be your airbox drain. This 45 degree fitting is
> supposed
> to have a check valve internal to this fitting. You would never know it is
> installed unless you know that it is there. This is the problem, most
> people
> think it is a standard AN fitting and will install a new fitting without
> the
> check valve at overhaul. With the check valve missing your engine sees
> this
> as an air induction leak and will idle rough and make the backfiring
> worse.
> A easy way to tell if your valve is working properly is to put your finger
> over the drain line with the engine running and see if you engine lowers
> its
> idle speed. I have also seen these check valves stuck open and just needs
> cleaning. I tried to order a new check valve when I found that mine had
> been
> changed out to a standard fitting after fighting this problem for 8 years.
> I
> never could get a good part number to order one and had to make my own. If
> yours is missing or gone bad I can tell you how to make one. Or you can
> install a PVC valve inline with your drain and it will work just as well.
> The PVC valve should close as your engine sucks air out of your airbox.
> This
> valve was supposed to drain the excess fuel that drains out of you
> injectors
> and into your airbox when you shut down your engine and suck closed when
> you
> start your engine.
>
> Andy Ellzey
>
>
> ----- Original Message ----- 
> From: "Dave Philipsen" <velocity at davebiz.com> 
> <mailto:velocity at davebiz.com>
> To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org> 
> <mailto:reflector at tvbf.org>
> Sent: Tuesday, August 15, 2006 10:38 PM
> Subject: REFLECTOR: Engine backfiring
>
>
>
>
> Here's a question perhaps for some of the engine experts:  I've got a
> STD FG with IO360-A1A engine.
> It has one standard magneto and one Jeff Rose electronic ignition.  The
> engine and oil cooling are not a
> problem even with OATs in the low 90s. But, I have a problem (it's not a
> huge problem) with backfiring
> during taxi *after* I land.  Taxiing before takeoff seems to be ok.  The
> backfiring happens maybe once
> every 30 seconds or so.  The engine also seems to run a little rough at
> this time.  I've tried running lean,
> running rich, running on just the magneto, running on just the
> electronic ignition.  None of these seems to
> prevent the backfiring during taxi.  The engine never seems to have
> problems before or during takeoff or
> during cruise or descent...just taxiing back after landing.
>
> I'm starting to think it's a vapor lock problem or something since the
> fuel flow is way down and the fuel is
> sitting in the lines longer and heating up.  I had the cowling off the
> other day and was checking the routing
> of the fuel injector lines and they don't appear to be routed near the
> exhaust manifolds or anything like that.
> I was thinking of maybe experimenting with some insulating material
> around the individual injector lines as
> well as the main fuel line.  Any ideas?
>
> -- 
> Dave Philipsen
> STDFG
> N171SP
>
>
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> -- 
>
> -
>     The most effectual engines for [pacifying a nation] are the public 
> papers... [A despotic] government always [keeps] a kind of standing army 
> of newswriters who, without any regard to truth or to what should be like 
> truth, [invent] and put into the papers whatever might serve the 
> ministers.
>
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>     Oct. 13, 1785. (*) ME 5:181, Papers 8:632
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