Today's Message Index:
----------------------
1. 12:10 AM - Please Read - Who is "Matt Dralle" and What are "The Lists"...? (Matt Dralle)
2. 10:03 AM - Re: AOPA Tiger article (TeamGrumman@aol.com)
3. 10:27 AM - Manifold Pressure (linn walters)
4. 12:50 PM - Re: manifold pressure (linn walters)
5. 06:12 PM - Re: Manifold Pressure (TeamGrumman@AOL.COM)
6. 06:24 PM - Re: Re: manifold pressure (TeamGrumman@AOL.COM)
7. 07:05 PM - Re: Manifold Pressure (linn walters)
8. 07:27 PM - Re: Re: manifold pressure (linn walters)
9. 11:51 PM - Re: Re: manifold pressure (TeamGrumman@AOL.COM)
Message 1
| INDEX | Back to Main INDEX |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Please Read - Who is "Matt Dralle" and What are "The |
Lists"...?
--> TeamGrumman-List message posted by: Matt Dralle <dralle@matronics.com>
Dear Listers,
Who is Matt Dralle and what exactly are these Lists? Well, I've been working in
the information technology industry for over 20 years primarily in computer
networking design and implementation. I've also had a rather extensive background
in web development and CGI design during this period.
I started the Matronics Email Lists back in 1990 with about 30 fellow RV builders
from around the world. Since that time, I have added 50 other kinds of aircraft
related Lists to the line up and numerous other List related services such
as the Archives and Search Engine just to name a few.
For the upmost in flexibility and reliability, I have chosen to run all of my own
servers here locally. Other support systems include a 1 Gigabit, fully switched
network infrastructure, a commercial-grade Netscreen firewall, a Barracuda
spam filter, a local T1 Internet router, and a commercial business T1 Internet
connection with static addressing.
The computer servers found here include two, dual processor Xeon Linux systems
dedicated to the email and web functions respectfully, and another P4 Linux system
serving as a remote storage disk farm for the archives, databases, and for
an on-line, hard drive-based backup system with 3.2 Terabytes of storage. This
entire system is protected by multiple commercial-grade uninterrupted power
supply (UPS) systems that assure the Lists are available even during a local
power outage!
I recently upgraded all of the computer racking infrastructure including new power
feeds and dedicated air conditioning for the room that serves as the Computer
Center for the Matronics Email Lists. Here's a new composite photo of the
List Computer Center following this Summer's upgrades!
http://www.matronics.com/MattDralle-ListComputerCenter.jpg
As you can see, I take running these Lists very seriously and I am dedicated to
providing an always-on, 24x7x365 experience for each and every Lister.
But building and running this system isn't cheap. As I've stated before, I don't
support any of these systems with commercial advertising on the Lists. It
is supported 100% through List member Contributions! That means you... and you...
and YOU!
To that end, I hold a List Fund Raiser each November and ask that members make
a small Contribution to support the continued operation and upgrade of this ever-expanding
system. Its solely YOUR Contributions that keep it running!
Please make a Contribution today to support these Lists!
http://www.matronics.com/contribution
Thank you!
Matt Dralle
Matronics Email List Administrator
Matt G Dralle | Matronics | PO Box 347 | Livermore | CA | 94551
925-606-1001 V | 925-606-6281 F | dralle@matronics.com Email
http://www.matronics.com/ WWW | Featuring Products For Aircraft
do not archive
Message 2
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: AOPA Tiger article |
--> TeamGrumman-List message posted by: TeamGrumman@aol.com
In a message dated 11/28/05 7:13:29 AM, Douglas.Weir@us.calyon.com writes:
> Gary,
> Did you also install the PowerFlow exhaust on your plane?=A0 Are you a
> believer?
>
>
Oh, yes, I forgot to say that. It does have the short stack Power Flow.
The power Flow exhaust system is very well designed right up to where they
attach the muffler to the plane. On the original setup, the muffler would=20hang
loosely and wobble back and forth. On the short stack, the support brace is
at such a poor angle that it is useless.
We had a new 182 Cessna do a hard landing here. When the cowling was off,=20I
noticed the muffler supported by a bracket mounted to the firewall. Clearly
a lot better way to support the muffler. SOOOOO, I mounted my short stack
so that the muffler has a descent support at the firewall.
Other-than-that, anything beats the poorly designed stock muffler. If I
could replace every stock muffler with the power flow, I would.
By-the-way, I got an additional 80 rpm at 12,500 feet with the power flow. =20
At 17,500 feet, I can still turn it 2650 rpm.
Gary
Message 3
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Manifold Pressure |
--> TeamGrumman-List message posted by: linn walters <lwalters2@cfl.rr.com>
I sent this to the Grumman Gang also so I apologize for the duplicate
posts!!!
I'm helping troubleshoot a 'burping' problem in an O-360. Yesterday,
on our flight in search of food, I took some data. We set the throttle
near 2300 at full rich. I only changed the mixture two turns at a time
and recorded RPM, Man Press, Fuel Flow and EGTs. Remember, the only
change was in mixture. What surprised me was the change in MP. It
changed from 21.7 to 22.5 from full rich to full lean. I don't
understand, so hopefully someone can tell me why it changed.
The burps start at around 10 turns from full rich with MP @ 22.0, FF at
8.2 GPH, RPM at 2320, and EGTs of 1407,1450, 1413, and 1364 (cyls 1-4)
The burps are significant, absent at full rich, and getting worse as the
engine is leaned. They're also not regular in frequency. The engine
does experience normal roughness when leaned too much, and is different
than the burps. The burps would be about the same intensity as total
ignition failure for a fraction of a second, and occur anywhere from
infrequent at richer settings to every 15 seconds at leaner settings.
Help me out here guys. I haven't a clue what's going on. Mags are new,
carb overhauled, new plugs and harness.
What should I look at next???
Linn
do not archive
--
Message 4
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: manifold pressure |
--> TeamGrumman-List message posted by: linn walters <lwalters2@cfl.rr.com>
Ron Levy wrote:
>>It's a FP prop. This plane has an engine analyzer installed and that's
>>where the data came from.
>>
>>
>[Levy] OK, then what did the RPM do when the MP went up, or did you throttle
>back to keep the 2300 RPM? Or was all this leaning done at full throttle?
>
>Ron
>
The RPM changed with leaning ...... and the pilots inability to hold
altitude really well ......and the throttle wasn't full. I don't have
much experience with MP, and was under the impression that it was
controlled solely by throttle, and that once the throttle was set, so
was the MP. I appreciate the input from Bob, Craig and Ron. I'm
learning!!!
So, back to the burping (term changed for the family-type email list :-)
) that we're experiencing. Throughout the leaning process, #3 was the
coolest, #1 and #4 we're roughly parallel, but #2, which started with a
delta of 25 below #4 (1230 Vs 1270) crossed #4 at 1375 and peaked 20
degrees higher (#2 @1465 and #4 @ 1445)
Peak for all 4 were at:
1 1425
2 1465
3 1400
4 1445
If that means anything!!!
When the burps start, the EGTs were:
1 1405
2 1450
3 1370
4 1415
Like I said, these burps are severe ...... like it took a slug of water
(none found anywhere) or the ignition shut down. Only for a heartbeat
..... which causes heartrate rise in the pilot/owner.
Open to any sugestions. Craig mentioned intake leaks .... but they've
done the pressure/soapy water thingy already with no apparent leaks. We
might do that again when the cowl is off next time. All the normal
things (ignition, timing, air intake ...... all have been looked at and
this is a recent rebuild. Time to think out of the box, I guess.
Linn
Message 5
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Manifold Pressure |
--> TeamGrumman-List message posted by: TeamGrumman@aol.com
Right after dubya-dubya 2, we'd set the idle on our Model-T hot rods using a
vacuum gage. I can talk like that now; I'm going to be a great-grandpa.
Seriously, we would set the timing and the idle mixture to maximum manifold
vacuum.
That's minimum manifold pressure.
- - - at what altitude was this?
Now, all that's all well and good, but, increasing the manifold pressure by
leaning, that's a new one. I HAVE noticed a change in manifold pressure,
running straight and level, due to outside pressure changes. Just a thought.
As for the burping, are you certain you aren't leaning to the point of
misfire? I know that you said it's different than a lean misfire. Just checking.
OK, that said, .... on two separate occasions, I experienced this exact same
burping in my Cheetah. I always leaned to near mis-fire. I attributed the
'burping' to the 1-piece venturi. The 'burping' happened right after the
change. I know that isn't the problem with your O-360 unless you have an
updraft carb.
What I did, was put on new mags, a new harness and get the perforated
main-jet nozzle for the carb. I never experienced the misfire after that.
Now, I know I don't need to ask, but I will. What does your JPI 700/800
tell you? Which cylinder is missing? When you download the data stream, and
look over the data, what are the EGTs doing when the burping occurs? With a
JPI 800, I know you have manifold pressure and RPM also being recorded. What
do they say?
WHAT? You don't have a JPI? I can get a good discount on one for you.
I would still try different mags. Do you have a Slick ignition harness?
I like them better than the cheaper ones. Still, if you have an engine
analyzer, it will tell you if it's one cylinder or all of them.
Gary
Message 6
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: manifold pressure |
--> TeamGrumman-List message posted by: TeamGrumman@aol.com
Linn,
Based on the drop in EGT, I'd agree the entire system is shutting down for a
second. How long is the drop on the data? Also, does the EGT go back up
when it wakes up again?
Disconnect the P-leads and try it. Maybe you have a shorted P-lead.
Gary
Message 7
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: Manifold Pressure |
--> TeamGrumman-List message posted by: linn walters <lwalters2@cfl.rr.com>
TeamGrumman@aol.com wrote:
>--> TeamGrumman-List message posted by: TeamGrumman@aol.com
>
>Right after dubya-dubya 2, we'd set the idle on our Model-T hot rods using a
>vacuum gage. I can talk like that now; I'm going to be a great-grandpa.
>
>Seriously, we would set the timing and the idle mixture to maximum manifold
>vacuum.
>
>
> That's minimum manifold pressure.
>
> - - - at what altitude was this?
>
>Now, all that's all well and good, but, increasing the manifold pressure by
>leaning, that's a new one. I HAVE noticed a change in manifold pressure,
>running straight and level, due to outside pressure changes. Just a thought.
>
This was definitely caused by leaning.
>As for the burping, are you certain you aren't leaning to the point of
>misfire? I know that you said it's different than a lean misfire. Just checking.
>
The burping starts at 10 turns of the mixture. No, it's not
calibrated! Lean is at 11 turns to 12. The EGTs rise 20 to 30
points(depending on which cylinder you look at) from burping to 'too
lean' roughness.
>OK, that said, .... on two separate occasions, I experienced this exact same
>burping in my Cheetah. I always leaned to near mis-fire. I attributed the
>'burping' to the 1-piece venturi. The 'burping' happened right after the
>change. I know that isn't the problem with your O-360 unless you have an
>updraft carb.
>
Hee, Hee, we do!!!
>What I did, was put on new mags, a new harness and get the perforated
>main-jet nozzle for the carb. I never experienced the misfire after that.
>
Do you think it was the main jet nozzle change that did the trick? That
hasn't been done yet. Don't know which venturi is in the carb either.
I'll ask.
>Now, I know I don't need to ask, but I will. What does your JPI 700/800
>tell you? Which cylinder is missing? When you download the data stream, and
>look over the data, what are the EGTs doing when the burping occurs? With a
>JPI 800, I know you have manifold pressure and RPM also being recorded. What
>do they say?
>
>WHAT? You don't have a JPI? I can get a good discount on one for you.
>
I think this one is an EI, but not sure. I'll check. It would be
really nice to be able to download the info and graph it on the computer
instead of a quadrille pad!!!
>I would still try different mags.
>
They've used 'borrowed' mags and new ones with new harness.
> Do you have a Slick ignition harness?
>
Not sure about the ignition/harness maker. I'll check that too.
>
>I like them better than the cheaper ones. Still, if you have an engine
>analyzer, it will tell you if it's one cylinder or all of them.
>
The burp is so short that it doesn't make any difference in the 1-3
points that the EGTs vary when not burping. I didn't check whether one
mag or the other made the problem worse or go away. That's for a later
flight.
Thanks for the comments. The carb jet change may be the ticket.
Linn
do not archive
>
>Gary
>
>
>
>
>
--
Message 8
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: manifold pressure |
--> TeamGrumman-List message posted by: linn walters <lwalters2@cfl.rr.com>
Whoa. I may have mis-typed!!! There is no drop in EGTs when the burps
occur. The engine monitor will float +/- a couple of points when it's
not burping so it's really hard to see the burp on the EGTs.
Linn
do not archive
TeamGrumman@AOL.COM wrote:
>--> TeamGrumman-List message posted by: TeamGrumman@aol.com
>
>Linn,
>
>Based on the drop in EGT, I'd agree the entire system is shutting down for a
>second. How long is the drop on the data? Also, does the EGT go back up
>when it wakes up again?
>
>Disconnect the P-leads and try it. Maybe you have a shorted P-lead.
>
>Gary
>
>
>
>
--
Message 9
| INDEX | Back to Main INDEX |
| PREVIOUS | Skip to PREVIOUS Message |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
| Subject: | Re: manifold pressure |
--> TeamGrumman-List message posted by: TeamGrumman@aol.com
It looks to me like the EGTs were 15 to 30 degrees lower.
> Whoa.=A0 I may have mis-typed!!!=A0 There is no drop in EGTs when the burps
> occur.=A0 The engine monitor will float +/- a couple of points when it's
> not burping so it's really hard to see the burp on the EGTs.
>
Peak for all 4 were at:
1=A0=A0 1425
2=A0=A0 1465
3=A0=A0 1400
4=A0=A0 1445
If that means anything!!!
When the burps start, the EGTs were:
1=A0=A0 1405
2=A0=A0 1450
3=A0=A0 1370
4=A0=A0 1415
Other Matronics Email List Services
These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.
-- Please support this service by making your Contribution today! --
|