REFLECTOR: Fuel Filters / Clogged Injectors

Fri Aug 14 18:58:22 CDT 2009

I'll do that.  Thanks, John.

Terry

From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of John Tvedte
Sent: Friday, August 14, 2009 16:30
To: Velocity Aircraft Owners and Builders list; jerry at jlbent.com
Subject: Re: REFLECTOR: Fuel Filters / Clogged Injectors

Terry,

I believe you are referring to the filter which is an Airflow Performance
supplied product.  The Factory may or may not obtain theirs from Airflow - I
am not sure.  The one supplied by Airflow - has a SS screen - and is a
lifetime filter.  If you have any questions or concerns, I'm sure Don @
Airflow would be happy to address them.

John

  _____  

From: reflector-bounces at tvbf.org [reflector-bounces at tvbf.org] On Behalf Of
Terry Miles [terrence_miles at hotmail.com]
Sent: Friday, August 14, 2009 1:53 PM
To: jerry at jlbent.com; 'Velocity Aircraft Owners and Builders list'
Subject: Re: REFLECTOR: Fuel Filters / Clogged Injectors

I just did my annual inspection.  The took the gold (factory engine kit)
fuel filter out and just back washed it a little.  It seems completely
clean.  Does that filter have a service life?  Or a specific periodic
maintenance/inspection procedure?

Thanks,

Terry

From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of jerry at jlbent.com
Sent: Friday, August 14, 2009 08:07
To: Velocity Aircraft Owners and Builders list
Subject: REFLECTOR: Fuel Filters / Clogged Injectors

It is important to understand that even a 40 micron filter (the one that is
part of the factory installation kit) did not prevent the clogging of
injectors on an IO540.  

This is a bit off the filter thread (but related) and even farther off the
original thread so I have started a new and more appropriately titled one.

-----------------------

I have been remiss in documenting this so here goes:

We chased this problem for WAY too long.  The engine had been fine and then
it started running rough.  All I can figure is that the finer fiberglass
particles get through the "stock" filter and then when the engine is
shutdown the fuel evaporates and some resin is deposited and carborizes in
the bore of the injector.  A few engine runs later, the injector is either
completely blocked or blocked enough to cause the other cylinders to be way
rich.  If one injector is blocked then an IO540 will run 16.6% rich and that
is just about too rich to run.  This happens due to the way fuel is
distributed in the injector system.  For any RPM MP setting, the air intake
servo sends to the spyder the amount of fuel appropriate for 6 cylinders.
This fuel is then distributed to the injectors according to the flow
characteristics of each line and injector combination (this is where GAMI
works to balance flow).  So, when one injector is obstructed, the other 5
cylinders will be sharing what doesn't go through the clogged injector.
This can be countered by leaning but the best you can do is a rough engine
with less than 83% power.  If you are in the air, find an airport!  Beli!
eve that a 5 cylinder IO 540 is not comfortable!

The general evidence for this is 5 cylinders with "wet" (black/sooty) plugs
and one that looks fine.  Since one cylinder is going LOP and the rest are
going ROP, the temps are not going to be a good diagnostic.

The fix is very simple.  Remove and clean all the injectors.  You will
probably find one that is obviously clogged (magnifying glass is a good
idea), any or all may be getting worse.  Be careful when reinstalling.
These injectors to distribution lines connectors are easly stripped.  The
directions are to bring them to "Finger Tight" and then 1/4 turn more.  This
can be a bit tricky.  The distribution line must be properly straight
aligned with the injector.  The only way I know to do this is by feel.  When
aligned you can screw the cap nut down until the distribution line won't
wiggle easily.  That's the magic "Finger Tight".

Many on this sight already know all of this and can correct and expand on
the information provided.  I know that this is an insidious problem and can
take months to diagnose on a fresh engine installation.  There are so many
variable that will provide the same behaviors and with a good filter that
look clean, it does not appear to be the problem.  I provide my experience
only as a amateur builder, not as a qualified A&P or especially a fuel
system expert.  It's all about the learning

Jerry Brainard
N202VB XLRG Building Slowly

-------Original Message-------
From: Dave Philipsen 
Subject: Re: REFLECTOR: Fuel Consumption Performance
Sent: Aug 13 '09 5:48pm

HYTEC45 at aol.com wrote:
> In a message dated 8/13/2009 1:55:48 PM Pacific Daylight Time, 
>  <http://mbox.jlbent.com/compose.php?to=velocity@davebiz.com>
velocity at davebiz.com writes:
>
>     The sump/drain acts as a gascolator itself. 
>
> True, however the cascolator has a 74 micron screen just in case any 
> "floaters" are lurking.
> TEC
>   
Good to know.

-- 
Dave Philipsen
Velocity STD FG
N83DP

_______________________________________________
To change your email address, visit
<http://www.tvbf.org/mailman/listinfo/reflector>
http://www.tvbf.org/mailman/listinfo/reflector

Visit the gallery!  www.tvbf.org/gallery
user:pw = tvbf:jamaicangoose
Check new archives: www.tvbf.org/pipermail
Check old archives:  <http://www.tvbf.org/archives/velocity/maillist.html>
http://www.tvbf.org/archives/velocity/maillist.html

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.tvbf.org/mailman/private/reflector/attachments/20090814/4ed608ae/attachment-0001.htm>