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rtmarshall(at)gotsky.com
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 Posted: Mon May 05, 2008 7:10 am Post subject: JabiruEngine-List Digest: 3 Msgs - 05/04/08 |
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Hello Jabiru users, On your Egt issues while not flying one,I have a lyc, I
was having some of the same issues a while back and in particular on a
cylinder that would not come up to within a few degrees of all the rest,
even after changing the injector nozzle, it was way cold. the reason was,
the cooling air going by the out side of the EGT probe, I wrapped the pipe
down about six inches and the temp came up. ! IMHO and FWIW. Bob
---
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BobsV35B(at)aol.com
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| Posted: Mon May 05, 2008 8:17 am Post subject: JabiruEngine-List Digest: 3 Msgs - 05/04/08 |
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Good Morning Bob and All,
The key point here is that the actual temperature means very little and there really is NO need for all of them to read the same. What we really want to know is how close the cylinder is running to a stoichiometric mixture. Peak EGT occurs close to that mixture.
On the lean side of stoichiometric, the engine will run cooler and on the rich side of stoichiometric, the engine will also run cooler.
Since there are so many variables introduced by probe placement and incidental airflow considerations, the actual temperature IS immaterial. What we need to do is slowly lean and see just where each cylinder peaks in relation to fuel flow. I see no way to do that exercise with Jabiru and it's BMW motorcycle BING carburetor.
Cooling or insulating your Lycoming was just messing around. It did nothing to adjust the mixture and that is what is important.
I sure wish someone would come up with a method whereby we could lean the Jabiru so as to determine just how well balanced the mixtures actually are.
On your Lycoming, that is fairly easy to do IF you have a good all cylinder monitor and a very accurate electronic fuel flow unit.
Happy Skies,
Old Bob
AKA
Bob Siegfried
Ancient Aviator
628 West 86th Street
Downers Grove, IL 60516
630 985-8502
Stearman N3977A
Brookeridge Air Park LL22
In a message dated 5/5/2008 10:11:36 A.M. Central Daylight Time, rtmarshall(at)gotsky.com writes:
| Quote: | --> JabiruEngine-List message posted by: "Bob & Toodie Marshall" <rtmarshall(at)gotsky.com>
Hello Jabiru users, On your Egt issues while not flying one,I have a lyc, I
was having some of the same issues a while back and in particular on a
cylinder that would not come up to within a few degrees of all the rest,
even after changing the injector nozzle, it was way cold. the reason was,
the cooling air going by the out side of the EGT probe, I wrapped the pipe
down about six inches and the temp came up. ! IMHO and FWIW. Bob
|
Wondering what's for Dinner Tonight? Get new twists on family favorites at AOL Food.
[quote][b]
| | - The Matronics JabiruEngine-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
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BobsV35B(at)aol.com
Guest
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| Posted: Mon May 05, 2008 8:31 am Post subject: JabiruEngine-List Digest: 3 Msgs - 05/04/08 |
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Good Morning Bob and All,
The key point here is that the actual temperature means very little and there really is NO need for all of them to read the same. What we really want to know is how close the cylinder is running to a stoichiometric mixture. Peak EGT occurs close to that mixture.
On the lean side of stoichiometric, the engine will run cooler and on the rich side of stoichiometric, the engine will also run cooler.
Since there are so many variables introduced by probe placement and incidental airflow considerations, the actual temperature IS immaterial. What we need to do is slowly lean and see just where each cylinder peaks in relation to fuel flow. I see no way to do that exercise with Jabiru and it's BMW motorcycle BING carburetor.
Cooling or insulating your Lycoming was just messing around. It did nothing to adjust the mixture and that is what is important.
I sure wish someone would come up with a method whereby we could lean the Jabiru so as to determine just how well balanced the mixtures actually are.
On your Lycoming, that is fairly easy to do IF you have a good all cylinder monitor and a very accurate electronic fuel flow unit.
Happy Skies,
Old Bob
AKA
Bob Siegfried
Ancient Aviator
628 West 86th Street
Downers Grove, IL 60516
630 985-8502
Stearman N3977A
Brookeridge Air Park LL22
In a message dated 5/5/2008 10:11:36 A.M. Central Daylight Time, rtmarshall(at)gotsky.com writes:
| Quote: | --> JabiruEngine-List message posted by: "Bob & Toodie Marshall" <rtmarshall(at)gotsky.com>
Hello Jabiru users, On your Egt issues while not flying one,I have a lyc, I
was having some of the same issues a while back and in particular on a
cylinder that would not come up to within a few degrees of all the rest,
even after changing the injector nozzle, it was way cold. the reason was,
the cooling air going by the out side of the EGT probe, I wrapped the pipe
down about six inches and the temp came up. ! IMHO and FWIW. Bob
|
Wondering what's for Dinner Tonight? Get new twists on family favorites at AOL Food.
[quote][b]
| | - The Matronics JabiruEngine-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?JabiruEngine-List |
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Peter H
Joined: 20 Mar 2007
Posts: 197
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| Posted: Mon May 05, 2008 1:40 pm Post subject: JabiruEngine-List Digest: 3 Msgs - 05/04/08 |
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Bob,
I replaced the Bing with a simple throttle body and two injectors. I have a potentiometer to over ride the ECU if necessary and this was useful when fixing fuel maps . I am monitoring EGT at #5 and #6. With the present map settings I have even EGT (about 690degC) at TOC but if I leave the throttle open and accelerate I see EGT 5 goes to 780degC ie almost 100 deg hotter, and the engine starts to shake because of uneven power strokes R to L.
I think the problem is caused because there is no intake manifold, only a 1/2L collector. I am building a 3.5L induction manifold using 64MM tube fittings and will be able to report on that soon.
Peter
From: owner-jabiruengine-list-server(at)matronics.com [mailto:owner-jabiruengine-list-server(at)matronics.com] On Behalf Of BobsV35B(at)aol.com
Sent: Tuesday, 6 May 2008 2:28 AM
To: jabiruengine-list(at)matronics.com
Subject: Re: JabiruEngine-List Digest: 3 Msgs - 05/04/08
Good Morning Bob and All,
The key point here is that the actual temperature means very little and there really is NO need for all of them to read the same. What we really want to know is how close the cylinder is running to a stoichiometric mixture. Peak EGT occurs close to that mixture.
On the lean side of stoichiometric, the engine will run cooler and on the rich side of stoichiometric, the engine will also run cooler.
Since there are so many variables introduced by probe placement and incidental airflow considerations, the actual temperature IS immaterial. What we need to do is slowly lean and see just where each cylinder peaks in relation to fuel flow. I see no way to do that exercise with Jabiru and it's BMW motorcycle BING carburetor.
Cooling or insulating your Lycoming was just messing around. It did nothing to adjust the mixture and that is what is important.
I sure wish someone would come up with a method whereby we could lean the Jabiru so as to determine just how well balanced the mixtures actually are.
On your Lycoming, that is fairly easy to do IF you have a good all cylinder monitor and a very accurate electronic fuel flow unit.
Happy Skies,
Old Bob
AKA
Bob Siegfried
Ancient Aviator
628 West 86th Street
Downers Grove, IL 60516
630 985-8502
Stearman N3977A
Brookeridge Air Park LL22
In a message dated 5/5/2008 10:11:36 A.M. Central Daylight Time, rtmarshall(at)gotsky.com writes:
| Quote: |
--> JabiruEngine-List message posted by: "Bob & Toodie Marshall" <rtmarshall(at)gotsky.com>
Hello Jabiru users, On your Egt issues while not flying one,I have a lyc, I
was having some of the same issues a while back and in particular on a
cylinder that would not come up to within a few degrees of all the rest,
even after changing the injector nozzle, it was way cold. the reason was,
the cooling air going by the out side of the EGT probe, I wrapped the pipe
down about six inches and the temp came up. ! IMHO and FWIW. Bob |
Wondering what's for Dinner Tonight? Get new twists on family favorites at AOL Food.
| Quote: | | http://www.matronics.com/Navigator?JabiruEngine-List |
0123456789
[quote][b]
| | - The Matronics JabiruEngine-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?JabiruEngine-List |
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BobsV35B(at)aol.com
Guest
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| Posted: Mon May 05, 2008 9:51 pm Post subject: JabiruEngine-List Digest: 3 Msgs - 05/04/08 |
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Good Evening Peter,
Sounds great! Be sure to let us know how things go.
Happy Skies,
Old Bob
AKA
Bob Siegfried
Ancient Aviator
628 West 86th Street
Downers Grove, IL 60516
630 985-8502
Stearman N3977A
Brookeridge Air Park LL22
In a message dated 5/5/2008 4:41:24 P.M. Central Daylight Time, peterjfharris(at)bigpond.com writes:
| Quote: |
Bob,
I replaced the Bing with a simple throttle body and two injectors. I have a potentiometer to over ride the ECU if necessary and this was useful when fixing fuel maps . I am monitoring EGT at #5 and #6. With the present map settings I have even EGT (about 690degC) at TOC but if I leave the throttle open and accelerate I see EGT 5 goes to 780degC ie almost 100 deg hotter, and the engine starts to shake because of uneven power strokes R to L.
I think the problem is caused because there is no intake manifold, only a 1/2L collector. I am building a 3.5L induction manifold using 64MM tube fittings and will be able to report on that soon.
Peter |
Wondering what's for Dinner Tonight? Get new twists on family favorites at AOL Food.
[quote][b]
| | - The Matronics JabiruEngine-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?JabiruEngine-List |
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Lynn Matteson
Joined: 10 Jan 2006
Posts: 2778
Location: Grass Lake, Michigan
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| Posted: Tue May 06, 2008 9:27 am Post subject: JabiruEngine-List Digest: 3 Msgs - 05/04/08 |
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Peter-
I envy you guys who have the room to build/install a plenum/manifold.
I do not, or I'd be doing it....I'd love to see yours when finished.
Lynn Matteson
Grass Lake, Michigan
Kitfox IV Speedster w/Jabiru 2200
flying w/503+ hrs
do not archive
On May 5, 2008, at 5:36 PM, Peter Harris wrote:
| Quote: | Bob,
I replaced the Bing with a simple throttle body and two injectors.
I have a potentiometer to over ride the ECU if necessary and this
was useful when fixing fuel maps . I am monitoring EGT at #5 and
#6. With the present map settings I have even EGT (about 690degC)
at TOC but if I leave the throttle open and accelerate I see EGT 5
goes to 780degC ie almost 100 deg hotter, and the engine starts to
shake because of uneven power strokes R to L.
I think the problem is caused because there is no intake manifold,
only a 1/2L collector. I am building a 3.5L induction manifold
using 64MM tube fittings and will be able to report on that soon.
Peter
From: owner-jabiruengine-list-server(at)matronics.com [mailto:owner-
jabiruengine-list-server(at)matronics.com] On Behalf Of BobsV35B(at)aol.com
Sent: Tuesday, 6 May 2008 2:28 AM
To: jabiruengine-list(at)matronics.com
Subject: Re: JabiruEngine-List Digest: 3 Msgs -
05/04/08
Good Morning Bob and All,
The key point here is that the actual temperature means very little
and there really is NO need for all of them to read the same. What
we really want to know is how close the cylinder is running to a
stoichiometric mixture. Peak EGT occurs close to that mixture.
On the lean side of stoichiometric, the engine will run cooler and
on the rich side of stoichiometric, the engine will also run cooler.
Since there are so many variables introduced by probe placement and
incidental airflow considerations, the actual temperature IS
immaterial. What we need to do is slowly lean and see just where
each cylinder peaks in relation to fuel flow. I see no way to do
that exercise with Jabiru and it's BMW motorcycle BING carburetor.
Cooling or insulating your Lycoming was just messing around. It did
nothing to adjust the mixture and that is what is important.
I sure wish someone would come up with a method whereby we could
lean the Jabiru so as to determine just how well balanced the
mixtures actually are.
On your Lycoming, that is fairly easy to do IF you have a good all
cylinder monitor and a very accurate electronic fuel flow unit.
Happy Skies,
Old Bob
AKA
Bob Siegfried
Ancient Aviator
628 West 86th Street
Downers Grove, IL 60516
630 985-8502
Stearman N3977A
Brookeridge Air Park LL22
In a message dated 5/5/2008 10:11:36 A.M. Central Daylight Time,
rtmarshall(at)gotsky.com writes:
<rtmarshall(at)gotsky.com>
Hello Jabiru users, On your Egt issues while not flying one,I have
a lyc, I
was having some of the same issues a while back and in particular on a
cylinder that would not come up to within a few degrees of all the
rest,
even after changing the injector nozzle, it was way cold. the
reason was,
the cooling air going by the out side of the EGT probe, I wrapped
the pipe
down about six inches and the temp came up. ! IMHO and FWIW. Bob
Wondering what's for Dinner Tonight? Get new twists on family
favorites at AOL Food.
http://www.matronics.com/Navigator?JabiruEngine-Listhttp://
forums.matronics.comhttp://www.matronics.com/contribution
forums.matronics.com_-
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contribution_-
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| | - The Matronics JabiruEngine-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
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_________________
Lynn
Kitfox IV-Jabiru 2200
N369LM |
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