REFLECTOR:INTAKE COMBUSTION AIR
Chuck Jensen
reflector@tvbf.org
Sun, 14 Sep 2003 11:08:12 -0400
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Bob,
I also have a 540 and went through some of same issues of imbalanced cooling
that you're facing. I looked at air cooling flow--good. I looked at
baffling--good, I looked at air in-leakage in the induction system--good, I
looked at fuel servo problems--good. I looked for a partially blocked fuel
injector(s)--good. I looked at injector delivery of a consistant fuel/air
balance--bad.
When I ran the GAMI lean test, sure enough, the #2 and #3 cylindars, my hot
ones, leaned out early (2+ gph--bad) faster than the rich cylinders. In
such a circumstance, there are two possilbe outcomes, 1) when you run ROP,
the majority of the cylinders are ROP but the hot ones are hot because they
are lean of peak (LOP), or 2) you attempt to run LOP for the majority of the
cylinders but the two hot (lean) cylinders are then starved for fuel and run
very rough with significant power loss.
It's hard to say if this truly is your problem but when I installed the
GAMInjectors, which are sized based on the initial lean testing, the "hot"
cylinders went away. There is a certain amount of guessing on the part of
GAMI in selectiong injectors based on the lean test results. They seem to
have 4 or 5 different capacity injectors. I can't say whether they enrich
the lean cylinders or lean the rich cylinders, but it doesn't really matter;
the target is to get an injector that will compensate for the disparity of
fuel/air mixture between cylinders. The desired end point is to get all of
the cylinders to lean out over a range of <0.5 gph.
After installation of the initial set of injectors, subsequent lean tests
are then run to determine which are the hot/cold cylinders. GAMI, at no
addition charge, will then supply new, better-educated-guess injectors to
swap out with the still-aberrant injectors. I suspect this process takes
about two evolutions, potentially three, to get the injector selection down
to where the cylinders all lean out at the same time. A small caveat;
GAMInjector's injector guess is only as good as the quality of your lean
test.
My testimonial is 1) it has reduced my lean spread from +2 gph to <1 gph
across the cylinders, 2) I'm able to cruise at almost 1 gph less for the
same power setting and "roughness, 3) my hot cylinders have pretty much
disappeared, 4) I'm not quite there yet, so I have one more swap-out to do
for the "perfect" set of balanced injectors.
It's something to think about. If you want to check it out, free of cost
(and not many things in aviation are free) download the simple lean test
procedure and data form from their web site http://www.gami.com/
<http://www.gami.com/> . P.S., Make sure you tell 'em I sent you so I get
my 25% cut (NOT)!
Chuck Jensen
Diversified Technologies
2680 Westcott Blvd
Knoxville, TN 37931
Phn: 865-539-9000 x25
Cell: 865-406-9001
Fax: 865-539-9001
cjensen@dts9000.com
-----Original Message-----
From: reflector-admin@tvbf.org [mailto:reflector-admin@tvbf.org]On Behalf Of
SlvEgl99@aol.com
Sent: Sunday, September 14, 2003 7:18 AM
To: reflector@tvbf.org
Subject: Re: REFLECTOR:INTAKE COMBUSTION AIR
I have an XL FG with Lycoming IO540, two oil coolers.
I have always had a bit of a cooling issue. Not so much that temps are high,
but that they are uneven between cylinders. The center two (3&4) are
significantly cooler than the end four. Thisa is sometimes 70 degrees or
more.
After a lot of time trying to get diverters in the ducting to move a greater
amount of air to the ends of the plenum, I took a hard look at how Lycoming
has the air flow controlled between the cylinders and noted that they have
baffles between the cylinders that force the cooling air to stay within the
cylinder fins nearly to the bottom of the cylinder. On the other hand, the
XL plenum stops half way down the front and rear cylinders, allowing the air
to "escape" from the cylinder fins at this point.
I also took a look at a a long EZ and how that engine is baffled. I saw that
the baffling has the air confined to the cylinders with just a small (2.5")
opening for the air to exit the fins.
By coincidence just this week I decided to extend the ends of the plenum to
near the bottom of the cylinders, cutting them off at the approximate length
of the Lycoming baffles.
How does it work? I don't know yet as I have just completed the job and have
not had a chance to fly it yet.
The other heat issue I have is that the front oil cooler puts too much heat
into the nose., and then into the cockpit. I have a piece of foam above the
canard inside the hatch cover to block the heat from the nose and insulated
it as well as I can by adding insulation around the body of the cooler and
insulating the oil lines. I point out that I have a FG, thus no nose gear
door to allow air into the nose. I have toyed with the idea of adding a
small vent to bring in cool air to this area.
Any thoughts or ideas or concerns?
Bob Wood
N658SE
XL FG Bob II
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<DIV><SPAN class=390464313-14092003><FONT face=Arial color=#0000ff
size=2>Bob,</FONT></SPAN></DIV>
<DIV><SPAN class=390464313-14092003><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=390464313-14092003><FONT face=Arial color=#0000ff size=2>I also
have a 540 and went through some of same issues of imbalanced cooling that
you're facing. I looked at air cooling flow--good. I looked at
baffling--good, I looked at air in-leakage in the induction system--good, I
looked at fuel servo problems--good. I looked for a partially blocked fuel
injector(s)--good. I looked at injector delivery of a consistant fuel/air
balance--bad. </FONT></SPAN></DIV>
<DIV><SPAN class=390464313-14092003><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=390464313-14092003><FONT face=Arial color=#0000ff size=2>When I
ran the GAMI lean test, sure enough, the #2 and #3 cylindars, my hot ones,
leaned out early (2+ gph--bad) faster than the rich cylinders. In such a
circumstance, there are two possilbe outcomes, 1) when you run ROP, the majority
of the cylinders are ROP but the hot ones are hot because they are lean of peak
(LOP), or 2) you attempt to run LOP for the majority of the cylinders but the
two hot (lean) cylinders are then starved for fuel and run very rough with
significant power loss.</FONT></SPAN></DIV>
<DIV><SPAN class=390464313-14092003><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=390464313-14092003><FONT face=Arial color=#0000ff size=2>It's
hard to say if this truly is your problem but when I installed the GAMInjectors,
which are sized based on the initial lean testing, the "hot" cylinders went
away. There is a certain amount of guessing on the part of GAMI in
selectiong injectors based on the lean test results. They seem to
have 4 or 5 different capacity injectors. I can't say whether they enrich
the lean cylinders or lean the rich cylinders, but it doesn't really matter; the
target is to get an injector that will compensate for the disparity of fuel/air
mixture between cylinders. The desired end point is to get all of the
cylinders to lean out over a range of <0.5 gph.</FONT></SPAN></DIV>
<DIV><SPAN class=390464313-14092003><FONT face=Arial color=#0000ff
size=2></FONT></SPAN> </DIV>
<DIV><FONT face=Arial><FONT size=2><FONT color=#0000ff><SPAN
class=390464313-14092003></SPAN><SPAN class=390464313-14092003>After
installation of the initial set of injectors, subsequent lean tests are then run
to determine which are the hot/cold cylinders. GAMI, at no addition
charge, will then supply new, better-educated-guess injectors to swap out
with the still-aberrant injectors. I suspect this process takes
about two evolutions, potentially three, to get the injector selection down
to where the cylinders all lean out at the same time. A small caveat;
GAMInjector's injector guess is only as good as the quality of your lean
test. </SPAN></FONT></FONT></FONT></DIV>
<DIV><FONT face=Arial><FONT size=2><FONT color=#0000ff><SPAN
class=390464313-14092003></SPAN></FONT></FONT></FONT> </DIV>
<DIV><FONT face=Arial><FONT size=2><FONT color=#0000ff><SPAN
class=390464313-14092003>My testimonial is 1) it has reduced my lean spread from
+2 gph to <1 gph across the cylinders, 2) I'm able to cruise at almost 1 gph
less for the same power setting and "roughness, 3) my hot cylinders have
pretty much disappeared, 4) I'm not quite there yet, so I have one more swap-out
to do for the "perfect" set of balanced injectors.
</SPAN></FONT></FONT></FONT></DIV>
<DIV><FONT face=Arial><FONT size=2><FONT color=#0000ff><SPAN
class=390464313-14092003></SPAN></FONT></FONT></FONT> </DIV>
<DIV><FONT face=Arial><FONT size=2><FONT color=#0000ff><SPAN
class=390464313-14092003>It's something to think about. If you want to
check it out, free of cost (and not many things in aviation are free) download
the simple lean test procedure and data form from their web site <A
href="http://www.gami.com/">http://www.gami.com/</A>. P.S., Make sure you
tell 'em I sent you so I get my 25% cut (NOT)!</SPAN></FONT></FONT></FONT></DIV>
<DIV><FONT face=Arial><FONT size=2><FONT color=#0000ff><SPAN
class=390464313-14092003></SPAN></FONT></FONT></FONT> </DIV>
<DIV><FONT face=Arial><FONT size=2><FONT color=#0000ff><SPAN
class=390464313-14092003></SPAN></FONT></FONT></FONT><FONT face=Arial
size=2>Ch</FONT><FONT face=Arial size=2>uck</FONT><FONT face=Arial size=2>
Jensen</FONT> <BR><FONT face=Arial color=#c0c0c0 size=1>Diversified
Technologies</FONT> <BR><FONT face=Arial color=#c0c0c0 size=1>2680 Westcott
Blvd</FONT> <BR><FONT face=Arial color=#c0c0c0 size=1>Knoxville, TN
37931</FONT> <BR><FONT face=Arial color=#c0c0c0 size=1>Phn:</FONT> <FONT
face=Arial color=#c0c0c0 size=1> </FONT> <FONT face=Arial
color=#c0c0c0 size=1>865-539-9000 x25</FONT> <BR><FONT face=Arial color=#c0c0c0
size=1>Cell:</FONT> <FONT face=Arial color=#c0c0c0
size=1> </FONT> <FONT face=Arial color=#c0c0c0
size=1>865-406-9001</FONT> <BR><FONT face=Arial color=#c0c0c0
size=1>Fax:</FONT><FONT face=Arial color=#c0c0c0
size=1> </FONT> <FONT face=Arial color=#c0c0c0
size=1>865-539-9001</FONT> <BR><FONT face=Arial color=#c0c0c0
size=1>cjensen@dts9000.com</FONT> </DIV>
<BLOCKQUOTE>
<DIV class=OutlookMessageHeader dir=ltr align=left><FONT face=Tahoma
size=2>-----Original Message-----<BR><B>From:</B> reflector-admin@tvbf.org
[mailto:reflector-admin@tvbf.org]<B>On Behalf Of
</B>SlvEgl99@aol.com<BR><B>Sent:</B> Sunday, September 14, 2003 7:18
AM<BR><B>To:</B> reflector@tvbf.org<BR><B>Subject:</B> Re: REFLECTOR:INTAKE
COMBUSTION AIR<BR><BR></FONT></DIV><FONT face=arial,helvetica><FONT lang=0
face=Arial size=2 FAMILY="SANSSERIF">I have an XL FG with Lycoming IO540, two
oil coolers.<BR><BR>I have always had a bit of a cooling issue. Not so much
that temps are high, but that they are uneven between cylinders. The center
two (3&4) are significantly cooler than the end four. Thisa is sometimes
70 degrees or more.<BR><BR>After a lot of time trying to get diverters in the
ducting to move a greater amount of air to the ends of the plenum, I took a
hard look at how Lycoming has the air flow controlled between the cylinders
and noted that they have baffles between the cylinders that force the cooling
air to stay within the cylinder fins nearly to the bottom of the cylinder. On
the other hand, the XL plenum stops half way down the front and rear
cylinders, allowing the air to "escape" from the cylinder fins at this
point.<BR><BR>I also took a look at a a long EZ and how that engine is
baffled. I saw that the baffling has the air confined to the cylinders with
just a small (2.5") opening for the air to exit the fins.<BR><BR>By
coincidence just this week I decided to extend the ends of the plenum to near
the bottom of the cylinders, cutting them off at the approximate length of the
Lycoming baffles.<BR><BR>How does it work? I don't know yet as I have
just completed the job and have not had a chance to fly it yet.<BR><BR>The
other heat issue I have is that the front oil cooler puts too much heat into
the nose., and then into the cockpit. I have a piece of foam above the canard
inside the hatch cover to block the heat from the nose and insulated it as
well as I can by adding insulation around the body of the cooler and
insulating the oil lines. I point out that I have a FG, thus no nose gear door
to allow air into the nose. I have toyed with the idea of adding a small vent
to bring in cool air to this area.<BR><BR>Any thoughts or ideas or
concerns?<BR><BR>Bob Wood<BR>N658SE<BR>XL FG Bob II</FONT>
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