X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail-fx0-f42.google.com ([209.85.161.42] verified) by logan.com (CommuniGate Pro SMTP 5.4.0) with ESMTPS id 5040562 for flyrotary@lancaironline.net; Sat, 02 Jul 2011 10:39:42 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.161.42; envelope-from=msteitle@gmail.com Received: by fxe23 with SMTP id 23so3464439fxe.1 for ; Sat, 02 Jul 2011 07:39:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=6dfZL61CCGaV5NhbYMjXKy4XMbZY+akXiA0/An5r1Lw=; b=kGWtYZfLLqcjWT8oiKbunrGYzCHdVhrpz1i2ZxLaUXLLBLYR5XnDhNUasXAndVWuQ8 2d0cAHgi4o3yvGEa2sn6qZaGLbmRCYRQIuLgNYID5abQHsqgdHxr7Ey1ufvD8jUq0cdb upu3LWdBNL2UPacz2U9rXNmrkGO3WTPDUQ0kQ= MIME-Version: 1.0 Received: by 10.223.5.17 with SMTP id 17mr2314989fat.25.1309617546220; Sat, 02 Jul 2011 07:39:06 -0700 (PDT) Received: by 10.223.86.206 with HTTP; Sat, 2 Jul 2011 07:39:06 -0700 (PDT) In-Reply-To: References: Date: Sat, 2 Jul 2011 09:39:06 -0500 Message-ID: Subject: Re: [FlyRotary] Re: Leaking injectors? From: Mark Steitle To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=0015174789e8a2568c04a717183e --0015174789e8a2568c04a717183e Content-Type: text/plain; charset=ISO-8859-1 Kelly, This was not done to work around leaky injectors (I have six new injectors) but to ensure that if I ever run a tank dry that the pump could re-prime itself. While doing ground testing I discovered that if I ran the fuel tank dry the EFI pump could not re-prime itself, resulting in a vapor-lock situation. The only way to get it pressurized again was to crack open the fitting near the fuel rail while running the pump and bleed off the air which would get the pump sucking fuel again. There was at least one incident involving an Eggenfellner a/c that had this problem which resulted in a forced landing. They came up with the "bleeder circuit" as a fix. I borrowed the idea from them. It is discussed on their web site. I've tested it and it works like a charm. I don't recall the exact size fitting I used. It was an old 2-stroke motorcycle jet that I had in my toolbox. Any small jet should work. Bobby Hughes also incorporated this design feature into his RV-10. I recommend it to everyone, or else don't run your tanks dry. The only thing that I can think of that would make this unnecessary is if this happens in flight your engine will *probably* continue to windmill which should keep the injectors cycling. This could allow enough air to pass through the system to eventually allow for a re-start. (This didn't happen with the Eggenfellner installation.) If this happens at low altitude you may not have enough time for the engine to re-start though. Personally, I feel this is such a simple fix, I didn't see any reason not to do it. Mark On Sat, Jul 2, 2011 at 8:52 AM, Kelly Troyer wrote: > Ernest, > Your EFI fuel pumps have a check valve in them and will hold > regulated pressure > for a long time or until leaky injectors relieve this > pressure..........Short of replacing > the injectors the fix is to put a pressure relief orifice from the > fuel pressure line to > the fuel return line......This is the band-aid fix commonly used for hi- > milage RX7's > and "Mazdatrix" even sells a kit for this (I made my own for my 88 > Rx7).............The > orifice needs to be small (I think I used 0.020).............The fuel pump > has enough > excess capacity to make up for the small amount of leakage when the engine > is > running...........Make the orifice very small...........I bought a kit of > micro sized bits > from "Harbor Freight Aircraft Supply"........<:)...........Mark Steitledid this for leaky > injectors on his 20B..........Jump in here Mark.........Do you recall what > orifice size > you used ??.............. > > Kelly Troyer > *"DYKE DELTA JD2" (Eventually)* > "13B ROTARY"_ Engine > "RWS"_RD1C/EC2/EM2 > "MISTRAL"_Backplate/Oil Manifold > "TURBONETICS"_TO4E50 Turbo > > *From:* Ernest Christley > *To:* Rotary motors in aircraft > *Sent:* Friday, July 1, 2011 11:23 PM > *Subject:* [FlyRotary] Leaking injectors? > > I was installing a coolant overflow bottle today, working right next to the > intake manifold. Kept smelling gas. Then I noticed a little puddle inside > the little depression formed by a modification I just added. The new > fiberglass didn't have any paint on it, so that is why I could see through > it. There was maybe an ounce of gas floating around in the bottom of the > manifold. > > Could I have been running so rich during my test run that an oz of gas was > left on the manifold walls? Or could it be that it dripped through a leaky > injector, even though I shut down by switching off the fuel pump in order to > relieve line pressure? > > I know some others have had problems with leaky injectors. Does anyone > have an idea for making them not quite so leaky? > > -- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: > http://mail.lancaironline.net:81/lists/flyrotary/List.html > > > --0015174789e8a2568c04a717183e Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Kelly,=A0

This was not done to work around leaky injecto= rs (I have six new injectors) but to ensure that if I ever run a tank dry t= hat the pump could re-prime itself. =A0While doing ground testing I discove= red that if I ran the fuel tank dry the EFI pump could not re-prime itself,= resulting in a vapor-lock situation. =A0The only way to get it pressurized= again was to crack open the fitting near the fuel rail while running the p= ump and bleed off the air which would get the pump sucking fuel again. =A0T= here was at least one incident involving an Eggenfellner a/c that had this = problem which resulted in a forced landing. =A0They came up with the "= bleeder circuit" as a fix. =A0I borrowed the idea from them. =A0It is = discussed on their web site. =A0I've tested it and it works like a char= m. =A0I don't recall the exact size fitting I used. =A0It was an old 2-= stroke motorcycle jet that I had in my toolbox. =A0Any small jet should wor= k. =A0Bobby Hughes also incorporated this design feature into his RV-10. = =A0I recommend it to everyone, or else don't run your tanks dry.

The only thing that I can think of that would make this= unnecessary is if this happens in flight your engine will probably = continue to windmill which should keep the injectors cycling. =A0This could= allow enough air to pass through the system to eventually allow for a re-s= tart. =A0(This didn't happen with the Eggenfellner installation.) =A0If= this happens at low altitude you may not have enough time for the engine t= o re-start though. =A0Personally, I feel this is such a simple fix, I didn&= #39;t see any reason not to do it. =A0=A0

Mark

On Sat, Jul 2, 2= 011 at 8:52 AM, Kelly Troyer <keltro@att.net> wrote:
Ernest,
=A0=A0=A0 Your=A0EFI fuel= pumps have a check valve in them and will hold regulated=A0pressure=
for a long time or until leaky injectors relieve this pressure..= ........Short of replacing=
the injectors the=A0fix is to put a pressure relief = orifice from the fuel=A0pressure li= ne=A0 to
the=A0fuel return line......This is the band-aid=A0= fix commonly used for hi-milage RX7's
and "Mazdatrix"= even sells a kit for this (I made my own for my 88 Rx7)......= .......The
orifice needs to be small (I think I used 0.020)...= ..........The fuel pump has enough
excess capacity to make up for the small amount of leakage when = the engine is=A0
running...........Make the orifice very small...........I=A0bought a kit of micro sized= bits
from "Harbor Freight Aircraft Supply"........<:)...= ........Mark Steitle did this for le= aky
injectors on his 20B..........Jump in here Mark.........Do you r= ecall what orifice size=
you used ??..............=A0=A0=A0=A0
=A0
Kelly Troyer
"DYKE DELTA JD2" (Eventually)=
"13B ROTARY"_ Engine
"RWS"_RD1C/EC2/EM2
"MISTRAL"_Ba= ckplate/Oil Manifold
"TURBONETICS"_TO4E50 = Turbo

From: Ernest Christley <echristley@nc.rr.com>
To: Rotary motors in aircraft <flyrotary@lancair= online.net>
Sent: Friday, July 1, 2011 1= 1:23 PM
Subject: [FlyRota= ry] Leaking injectors?

I was installing a coolant overflow bo= ttle today, working right next to the intake manifold.=A0 Kept smelling gas= .=A0 Then I noticed a little puddle inside the little depression formed by a modification I just added.= =A0 The new fiberglass didn't have any paint on it, so that is why I co= uld see through it.=A0 There was maybe an ounce of gas floating around in t= he bottom of the manifold.

Could I have been running so rich during my test run that=A0 an oz of g= as was left on the manifold walls?=A0 Or could it be that it dripped throug= h a leaky injector, even though I shut down by switching off the fuel pump = in order to relieve line pressure?

I know some others have had problems with leaky injectors.=A0 Does anyo= ne have an idea for making them not quite so leaky?

--
Homepage:=A0 http://www.flyrotary.com/
Archive and UnSub:=A0 = http://mail.lancaironline.net:81/lists/flyrotary/List.html


<= /font>

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