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[166.147.113.188]) by mx.google.com with ESMTPS id g4sm89079407yhf.12.2012.05.22.08.51.09 (version=TLSv1/SSLv3 cipher=OTHER); Tue, 22 May 2012 08:51:18 -0700 (PDT) Subject: Re: [LML] 360 still surging References: From: Berni Breen Content-Type: multipart/alternative; boundary=Apple-Mail-B108B238-AB55-43AB-AA57-E6373522A0C1 X-Mailer: iPhone Mail (9B206) In-Reply-To: X-Original-Message-Id: X-Original-Date: Tue, 22 May 2012 10:51:02 -0500 X-Original-To: Lancair Mailing List Content-Transfer-Encoding: 7bit Mime-Version: 1.0 (1.0) X-Gm-Message-State: ALoCoQlLuFYvC2A0ci0Wl5vLfU/3pyCLeKYut6bGzzxc7TeTTlUwqnLVQYHuHC5vef8526ey6GXn --Apple-Mail-B108B238-AB55-43AB-AA57-E6373522A0C1 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=utf-8 Hi Craig: I am going to pull vacuum on my fuel system from the servo back to the fuel s= elector in an attempt to discover any possible air leaks. =20 My issue is not a new one nor does it seem to be worsening.=20 I agree with your assessment that my engine driven pump may be a contributin= g factor. Thanks for your input. Berni Breen Sent from my iPhone On May 22, 2012, at 8:32 AM, Craig Berland wrote: > Berni, > I agree with your diagnosis that fuel vapor is causing your problem. > - I am surprised that the fuel pump on low does not solve the pro= blem. It did on my IV-P yesterday after breakfast in Arizona. After a few m= inutes the low pump was not required. > - The engine mounted pump does not =E2=80=9Csuck=E2=80=9D fuel ve= ry well and any vapor in the line will cause you grief. The engine mounted p= ump may be getting worn with time and a rebuild may help=E2=80=A6.I know I a= m using a lot of =E2=80=9Cmays=E2=80=9D. > - Some ideas from me=E2=80=A6 > o Make sure the low boost pump is working=E2=80=A6.turn it on and listen= before starting engine. This is now on my check list. It should help. > o If the low boost is running and does not solve the surge problem then t= urn on the high boost and use the mixture knob to get the same fuel rate. Le= an for best idle. > o If the engine runs smooth on high boost=E2=80=A6.then look for air see= ping into the fuel lines. Look at every joint between the fuel tank(s) and t= he engine mounted fuel pump. If no leaks can be found, I would rebuild the e= ngine mounted pump or even better replace it. Aluminum housings for any kind= of positive displacement pump is problematic. Just one of many issues=E2=80= =A6. it is possible the bores in your pump are a little too big for the impe= llers=E2=80=A6even though they are within print or service tolerance. Heat a= nd low RPM is the enemy. The impellers are steel and the housing is aluminu= m. The coefficient of thermal expansion is greater for aluminum. The pump=E2= =80=99s ability to pump is therefore reduced at low RPM when it is hot. > - The one caution I would hope to communicate. If this issue is s= omething new, it may be the early warning of an engine pump failure. > Craig Berland > IV-P N7VG > =20 > Many of you guys have offered suggestions to help me remedy my ongoing eng= ine surge challenge. As a reminder...my fuel injected IO360 displays a very= pronounced surge during idle and taxi following a flight and brief shutdown= /restart. The problem never occurs when the engine iis cool. =20 > =20 > I have tried suggestions such as ground running the engine at 1700 rpm for= extended periods following a restart in an attempt to get some air moving t= hrough the cowl but that has resulted in limited success. So far my only re= medy is to let the engine sit for a long enough period to let it cool signif= icantly. If I do, I have zero issues with surging. > =20 > I even removed my fuel injector servo and sent it off for overhaul (not an= inexpensive undertaking) as another attempt to remedy my problem. That ide= a does not address what I firmly believe to be the problem, heat causing fue= l vapor lock, but I tried it anyway. I reinstalled the servo yesterday and t= est flew. The plane performed flawlessly as it always does following a firs= t start. When I returned home and let it sit for 20 minutes, restarted and w= ent to taxi, the surge was just as pronounced as ever. > =20 > All of my fuel lines are insulated and fire sleeved. The only exposed lin= es are the small lines that run up to the spider on the top of the engine. I= do not have any fuel leaks. Turning on my electric fuel pump, while increa= sing fuel pressure from 20 to 25 psi, does not remedy the surge issue. > =20 > As posted here before I have taken the active and lifted off several times= with this surge issue going on as the surge quits once I apply full throttl= e. As several of you have pointed out this is not a safe way to proceed the= refore I am again asking for ideas/suggestions from you guys. > =20 > Many years ago in my drag racing days me and several of my friends would i= nstall a cooling can to cool down the fuel and therefore (we believed) helpe= d us produce more power. We would use a coffee can, insert a coil of copper= fuel line in the can, put this contraption in line (fuel line) fill it and f= ill it with ice prior to a run. While this is not a practical long term sol= ution, is this the kind of thing I should be doing to prove/disprove my beli= ef that I have a vapor lock issue? > I sincerely appreciate any and all suggestions! > Berni Breen > Lancair 360 > =20 > =20 >=20 >=20 >=20 --Apple-Mail-B108B238-AB55-43AB-AA57-E6373522A0C1 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=utf-8
Hi Craig:

I am going to pull vacuum on my fuel system from the servo back to t= he fuel selector in an attempt to discover any possible air leaks.  

My issue is not a new one nor does it seem to be wors= ening. 

I agree with your assessment that my e= ngine driven pump may be a contributing factor.

Tha= nks for your input.

Berni Breen
Sent from my iPhone

On May 22, 2012, at 8:32 AM, Craig Berland <cberland@systems3.net> wrote:

Berni,

I agree with your d= iagnosis that fuel vapor is causing your problem.

-          <= /span>I am surprised that the fuel pump on low do= es not solve the problem.  It d= id on my IV-P yesterday after breakfast in Arizona.  After a few minutes the low pump was not required.

-     &n= bsp;    The engine mounted p= ump does not =E2=80=9Csuck=E2=80=9D fuel very well and any vapor in the line= will cause you grief.  The eng= ine mounted pump may be getting worn with time and a rebuild may help=E2=80=A6= .I know I am using a lot of =E2=80=9Cmays=E2=80=9D.

-         = Some ideas from me=E2=80=A6

o   <= /span>Make sure the low boost pump is working=E2=80=A6.turn it o= n and listen before starting engine.  <= /span>This is now on my check list.  <= /span>It should help.

o   If the low boost is ru= nning and does not solve the surge problem then turn on the high boost and u= se the mixture knob to get the same fuel rate. Lean for best idle.

o   If the engine runs smooth on high boost=E2=80=A6.the= n look for air seeping into the fuel lines.=   Look at every joint between the fuel tank(s) and the engine mo= unted fuel pump.  If no leaks c= an be found, I would rebuild the engine mounted pump or even better replace i= t. Aluminum housings for any kind of positive displacement pump is problemat= ic.  Just one of many issues=E2= =80=A6. it is possible the bores in your pump are a little too big for the i= mpellers=E2=80=A6even though they are within print or service tolerance. Hea= t and low RPM is the enemy.  Th= e impellers are steel and the housing is aluminum.  The coefficient of thermal expansion is greater for alu= minum.  The pump=E2=80=99s abil= ity to pump is therefore reduced at low RPM when it is hot.

-       &nb= sp;  The one caution I would hope to c= ommunicate.  If this issue is s= omething new, it may be the early warning of an engine pump failure.

Craig Berland

IV-P N7VG

=  

Many of you guys have offered suggest= ions to help me remedy my ongoing engine surge challenge.  As a reminde= r...my fuel injected IO360 displays a very pronounced surge during idle and t= axi following a flight and brief shutdown/restart.  The problem never o= ccurs when the engine iis cool.  

 

I have tried sug= gestions such as ground running the engine at 1700 rpm for extended periods f= ollowing a restart in an attempt to get some air moving through the cowl but= that has resulted in limited success.  So far my only remedy is to let= the engine sit for a long enough period to let it cool significantly.  = ;If I do, I have zero issues with surging.

 

I e= ven removed my fuel injector servo and sent it off for overhaul (not an inex= pensive undertaking) as another attempt to remedy my problem.  That ide= a does not address what I firmly believe to be the problem, heat causing fue= l vapor lock, but I tried it anyway.  I reinstalled the servo yesterday= and test flew.  The plane performed flawlessly as it always does follo= wing a first start.  When I returned home and let it sit for 20 minutes= , restarted and went to taxi, the surge was just as pronounced as ever.=

 

=

All of my fuel lines are insulated and fire sleeved. &= nbsp;The only exposed lines are the small lines that run up to the spider on= the top of the engine. I do not have any fuel leaks.  Turning on my el= ectric fuel pump, while increasing fuel pressure from 20 to 25 psi, does not= remedy the surge issue.

 

As posted here before I h= ave taken the active and lifted off several times with this surge issue goin= g on as the surge quits once I apply full throttle.  As several of you h= ave pointed out this is not a safe way to proceed therefore I am again askin= g for ideas/suggestions from you guys.

 

Many years= ago in my drag racing days me and several of my friends would install a coo= ling can to cool down the fuel and therefore (we believed) helped us produce= more power.  We would use a coffee can, insert a coil of copper fuel l= ine in the can, put this contraption in line (fuel line) fill it and fill it= with ice prior to a run.  While this is not a practical long term solu= tion, is this the kind of thing I should be doing to prove/disprove my belie= f that I have a vapor lock issue?

I sincerely appreciate any and all suggestions!

Berni Breen

Lancair 360

&= nbsp;

 

=



= --Apple-Mail-B108B238-AB55-43AB-AA57-E6373522A0C1--