Today's Message Index:
----------------------
1. 05:47 AM - Re: Re: 320-E2G sump question (Stucklen, Frederic W UTPWR)
2. 06:58 AM - Re: 320-E2G sump question (Gary Casey)
3. 09:05 AM - Re: Re: 320-E2G sump question (James Baldwin)
4. 10:28 AM - Re: Re: 320-E2G sump question (TeamGrumman@AOL.COM)
5. 04:26 PM - Re: Re: 320-E2G sump question (Jim Baker)
6. 04:59 PM - Re: Re: 320-E2G sump question (James Baldwin)
7. 06:09 PM - Re: Re: 320-E2G sump question (flyv35b)
8. 06:24 PM - Re: Re: 320-E2G sump question (James Baldwin)
9. 08:09 PM - Re: Re: 320-E2G sump question (Dww0708@aol.com)
10. 09:14 PM - Re: Re: 320-E2G sump question (Jim Baker)
Message 1
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Cc: "'Dww0708@aol.com'" <Dww0708@aol.com>, "'glcasey@adelphia.net'" <glcasey@adelphia.net>
| Subject: | Re: RE: 320-E2G sump question |
--> Engines-List message posted by: "Stucklen, Frederic W UTPWR" <Fred.Stucklen@UTCFuelCells.com>
David, Gary,
Veternman crossover exhaust: I think his company name is High Mountain
Exhaust.
Standard system for most RV's.....
The idle cutoff test worked fine, with a 100 RPM rise, so I'm sure there
aren't any
intake leaks. I've looked very carefully at all intake components and can't
find any
leaks. I've even performed checks to find cracks (exterior surface powder &
carb
cleaner into intakes/exhaust ports, compression checks, visual checks)....
Trial & Error approach: I'd like to think that I've taken a lot of data
that characterizes
just how the engine is operating. I have documented everything: fuel flow,
manifold
pressure, OAT, EGT, CHT, throttle position, mixture position, RPM, oil temp
&
pressure, etc.... The ONLY relationship to the poor EGT's & CHT's seems to
be
throttle position.
By the way, Bart Lablond (Aero Sport Power) has also looked at this engine
and can't seem to find why it's behaving the way it is..... He ran it in a
test cell, I've
run it in the plane, so the induction system (major difference) might still
be the
culprit.
I have checked the dry tappet clearances and they are within the Lycoming
specs...
Induction System: I'm using Van's standard FAB320 Air box. This is a
snorkel type
airbox that utilizes the lower cowl shape (snorkel) to feed air into a short
snorkel,
then into a larger chamber (much like a car airbox). The air filter is
mounted to
the bottom of the carb (Oval shaped with top/bottom plates). I have tried
to
modify the airflow into the filter box area by placing a wedge in front of
the filter
to divert some of the ram air flow. This didn't seem to help at all.
Since this is the second RV-6A that I've built (the first didn't have
these problems)
I've had a chance to compare the two induction systems. The first RV did
have
a larger volume area around the filter. This probably allowed better
distribution of
the air around the filter. I've ordered a new fiberglass air box part, and
plan on
installing it with modifications that will increase the airbox volume.
(Unfortunately,
Van has made some cowl, and engine mount changes that don't allow for the
use of his original airbox.) The air filter is the same....
I have experimented with the current air box. Putting a hole
in the bottom of the box (allowing air to enter/exit into the lower cowl)
did show
a significant change in the EGT/CHT patterns. The basic problem didn't go
away,
just changed how the engine breaths.
So that is the path that I'm going down next........ A modified airbox to
increase
the volume. I'd also like to run the engine without a filter to see what
happens to
the EGT/CHT patterns at various throttle settings. The filter should
actually result
in better airflows into the carb, but I need to know what it does without
it.
Fred Stucklen
RV-6A N926RV
vetterman? The idle cut off check is kind of an induction tube
integitidy
check,it proofs if you have vacuum leaky pipes. Vacuum is strongest
at idle
RPMs and a sucking leak will inhibit the proper RPM rise ( lean out )
at Idle
cutoff indicating lean condition. I know Lyc uses an oil heated
induction
manifold, Helps atomization. If the carb heat is leaking it can
adversely affect
the fuel air ratio. Any way looks like you have been trial and
erroring it.
The industry is like that. I am curious, Lyc operators manual? I
have
one, the thing that comes to me is what is the manifold pressure
doing? Is
there a curve trend that should/would mirror you other parameters?
Manifold
pressure at pressure altitude and OAT. Manifold pressure is the power
indicator. Then there is the basic push rod clearance with dry tap
it. Very
important to brake horses and volumetric effeciency.Selection of push
rod lengths
are how to adjust dry tappet clearance. Some might say that that
valve timing
issue would lead to engine roughness and it should but needs
confirmed. Very
basic. If I was a Lyc tech rep I would verify all this before before
experimenting away from the basic engine design. Have read about the
intake and
exhaust rocker arm movements and making sure consistent to other
cylinders. Are
all the correct part number items include in proper engine build up.
David
Message 2
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| Subject: | Re: 320-E2G sump question |
--> Engines-List message posted by: Gary Casey <glcasey@adelphia.net>
A couple more comments:
It looks like you correctly found out that throttle position makes a
difference. Sometimes it is better for the throttle to be full open
and other times it is better with the throttle partly closed or even
past fully open, deflecting the flow the other way. There is nothing
wrong with running with a partially closed throttle as the last maybe
20 degrees of rotation won't give any more air flow anyway.
Another observation - these engines are running in certified aircraft
and from you description I'm sure they don't have the problem - or at
least not so serious as to cause a problem. Since the engine itself
(sump, runners, carb) is of a standard configuration, what else is
different. The engine configuration probably doesn't need fixing.
Some have argued that the exhaust system could play a role, but I
reject that notion as at the rpm you are running there isn't much in
the way of tuning or pulsation effects that will be noticeable.
Also, any cam wear or valve clearance issues will only result in
slight power differences between cylinders, not large mixture
variations.
I still strongly suspect the carb inlet configuration. What is it like?
Gary
Message 3
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| Subject: | Re: RE: 320-E2G sump question |
--> Engines-List message posted by: James Baldwin <jamesbaldwin@dc.rr.com>
Fred -
Sounds like you've zeroed in on your engine's performance pretty
accurately. Before you get your knickers in a real knot, realize you
are collecting data at a level few people do with what production
aircraft your engine is in. My friend and I both had Grumman Cheetahs
with the carburated O320s. He installed the four cyl JPI EGT/CHT probe
system very accurately i.e. all the CHT probes were screw-in and the EGT
probes were positioned as close as possible to be in the same position
relative to the exhaust outlet per JPI install instructions. As an
engineer I was very interested because we were going to really get some
improved BSFC out of these engines. (we thought). Long story short, we
experienced exactly what you are seeing and in my humble opinion, you
will not be able to tighten the observed spread in EGT performance with
respect to throttle position in all cases. That's one reason why the
manufacturers eventually went to the mechanical fuel injection systems
in use today. They can tune each cylinder as if it were an individual
engine and not worry about how the fuel is distributed. Wide open
throttle is what we settled for and used altitude as the variable for
desired percent power. Don't waste any more time, go get some fuel
injection for it and spend your time tuning the injection nozzles to
tighten your EGT spread. Then you can go after fine tuning of the
cooling baffles to even out the CHT spread. JBB
Stucklen, Frederic W UTPWR wrote:
>--> Engines-List message posted by: "Stucklen, Frederic W UTPWR" <Fred.Stucklen@UTCFuelCells.com>
>
>David, Gary,
>
> Veternman crossover exhaust: I think his company name is High Mountain
>Exhaust.
>Standard system for most RV's.....
> The idle cutoff test worked fine, with a 100 RPM rise, so I'm sure there
>aren't any
>intake leaks. I've looked very carefully at all intake components and can't
>find any
>leaks. I've even performed checks to find cracks (exterior surface powder &
>carb
>cleaner into intakes/exhaust ports, compression checks, visual checks)....
> Trial & Error approach: I'd like to think that I've taken a lot of data
>that characterizes
>just how the engine is operating. I have documented everything: fuel flow,
>manifold
>pressure, OAT, EGT, CHT, throttle position, mixture position, RPM, oil temp
>&
>pressure, etc.... The ONLY relationship to the poor EGT's & CHT's seems to
>be
>throttle position.
> By the way, Bart Lablond (Aero Sport Power) has also looked at this engine
>and can't seem to find why it's behaving the way it is..... He ran it in a
>test cell, I've
>run it in the plane, so the induction system (major difference) might still
>be the
>culprit.
> I have checked the dry tappet clearances and they are within the Lycoming
>specs...
>
> Induction System: I'm using Van's standard FAB320 Air box. This is a
>snorkel type
>airbox that utilizes the lower cowl shape (snorkel) to feed air into a short
>snorkel,
>then into a larger chamber (much like a car airbox). The air filter is
>mounted to
>the bottom of the carb (Oval shaped with top/bottom plates). I have tried
>to
>modify the airflow into the filter box area by placing a wedge in front of
>the filter
>to divert some of the ram air flow. This didn't seem to help at all.
> Since this is the second RV-6A that I've built (the first didn't have
>these problems)
>I've had a chance to compare the two induction systems. The first RV did
>have
>a larger volume area around the filter. This probably allowed better
>distribution of
>the air around the filter. I've ordered a new fiberglass air box part, and
>plan on
>installing it with modifications that will increase the airbox volume.
>(Unfortunately,
>Van has made some cowl, and engine mount changes that don't allow for the
>use of his original airbox.) The air filter is the same....
> I have experimented with the current air box. Putting a hole
>in the bottom of the box (allowing air to enter/exit into the lower cowl)
>did show
>a significant change in the EGT/CHT patterns. The basic problem didn't go
>away,
>just changed how the engine breaths.
> So that is the path that I'm going down next........ A modified airbox to
>increase
>the volume. I'd also like to run the engine without a filter to see what
>happens to
>the EGT/CHT patterns at various throttle settings. The filter should
>actually result
>in better airflows into the carb, but I need to know what it does without
>it.
>
>Fred Stucklen
>RV-6A N926RV
>
>
>
>
> vetterman? The idle cut off check is kind of an induction tube
>integitidy
> check,it proofs if you have vacuum leaky pipes. Vacuum is strongest
>at idle
> RPMs and a sucking leak will inhibit the proper RPM rise ( lean out )
>at Idle
>
> cutoff indicating lean condition. I know Lyc uses an oil heated
>induction
> manifold, Helps atomization. If the carb heat is leaking it can
>adversely affect
>
> the fuel air ratio. Any way looks like you have been trial and
>erroring it.
>
> The industry is like that. I am curious, Lyc operators manual? I
>have
> one, the thing that comes to me is what is the manifold pressure
>doing? Is
>
> there a curve trend that should/would mirror you other parameters?
>Manifold
> pressure at pressure altitude and OAT. Manifold pressure is the power
>
> indicator. Then there is the basic push rod clearance with dry tap
>it. Very
>
> important to brake horses and volumetric effeciency.Selection of push
>rod lengths
>
> are how to adjust dry tappet clearance. Some might say that that
>valve timing
>
> issue would lead to engine roughness and it should but needs
>confirmed. Very
> basic. If I was a Lyc tech rep I would verify all this before before
> experimenting away from the basic engine design. Have read about the
>intake and
>
> exhaust rocker arm movements and making sure consistent to other
>cylinders. Are
>
> all the correct part number items include in proper engine build up.
>David
>
>
>
>
>
>
>
>
>
Message 4
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| Subject: | Re: 320-E2G sump question |
--> Engines-List message posted by: TeamGrumman@aol.com
In a message dated 2/15/06 7:00:44 AM, glcasey@adelphia.net writes:
> There is nothing=A0
> wrong with running with a partially closed throttle as the last maybe=A0
> 20 degrees of rotation won't give any more air flow anyway.
>
Not sure if you've tried this, (I haven't read all of the emails) but, try a
little carb heat at different throttle positions. I have an O360 with the
JPI 800. Carb heat has shown to move the EGT spread around at different
throttle settings.
Message 5
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| Subject: | Re: RE: 320-E2G sump question |
--> Engines-List message posted by: "Jim Baker" <jlbaker@telepath.com>
> That's one reason why the manufacturers eventually went to the
> mechanical fuel injection systems in use today. They can tune
each
> cylinder as if it were an individual engine and not worry about how
> the fuel is distributed. >
Well, that's partly true. FI is a whole lot better than carburetion in
terms of getting the right amount to each port.....avoiding having it
robbed from one port to someplace in the induction runner or to
another intake port is still a problem. I see about 125F difference
from top to bottom on my IO520. Unless you can do direct injection,
there's always some interference in the process at some given
RPM(s).
Jim Baker
580.788.2779
'71 SV, 492TC
Elmore City, OK
Message 6
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| Subject: | Re: RE: 320-E2G sump question |
--> Engines-List message posted by: James Baldwin <jamesbaldwin@dc.rr.com>
Jim -
The Cont 520 series is well known for its air/fuel mixture distribution
problem. That of course is what the calibrated injector nozzles from
George Braly at GAMI are all about. Are you using the GAMI nozzles in
your airplane? The A36 with the Tornado Alley Turbo normalizer I fly
has them and the spread is minimal and lean of peak cruise is very
smooth and economical. I don't have the spread at my fingertips here
because I actually only monitor TIT during operation. JBB
Jim Baker wrote:
>--> Engines-List message posted by: "Jim Baker" <jlbaker@telepath.com>
>
>
>
>>That's one reason why the manufacturers eventually went to the
>>mechanical fuel injection systems in use today. They can tune
>>
>>
>each
>
>
>>cylinder as if it were an individual engine and not worry about how
>>the fuel is distributed. >
>>
>>
>
>
>Well, that's partly true. FI is a whole lot better than carburetion in
>terms of getting the right amount to each port.....avoiding having it
>robbed from one port to someplace in the induction runner or to
>another intake port is still a problem. I see about 125F difference
>from top to bottom on my IO520. Unless you can do direct injection,
>there's always some interference in the process at some given
>RPM(s).
>
>
>Jim Baker
>580.788.2779
>'71 SV, 492TC
>Elmore City, OK
>
>
>
>
>
>
>
>
>
Message 7
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| Subject: | Re: RE: 320-E2G sump question |
--> Engines-List message posted by: "flyv35b" <flyv35b@ashcreekwireless.com>
It's not the absolute EGT or even the difference from one cylinder to
another that is the most important, but whether or not all cylinders reach
peak EGT at close to the same time and mixture control position. Granted,
this will change with throttle position and rpm and maybe other things but
if the spread in fuel flow from the first cylinder to reach peak to the last
is about .25 gph (on an IO-520 say) then you have a pretty even mixture
distribution and the engine will run smooth on the lean side of peak EGT.
You can have 2 different cylinders that are 50F or more apart temperature
wise but reach peak EGT at the very same time. The GAMI injectors taylor
the fuel flow to match the uneven airflow distribution and thereby hopefully
have all cylinders reach peak EGT at close to the same time.
Cliff
----- Original Message -----
From: "James Baldwin" <jamesbaldwin@dc.rr.com>
Sent: Wednesday, February 15, 2006 4:55 PM
Subject: Re: Engines-List: RE: 320-E2G sump question
> --> Engines-List message posted by: James Baldwin <jamesbaldwin@dc.rr.com>
>
> Jim -
> The Cont 520 series is well known for its air/fuel mixture distribution
> problem. That of course is what the calibrated injector nozzles from
> George Braly at GAMI are all about. Are you using the GAMI nozzles in
> your airplane? The A36 with the Tornado Alley Turbo normalizer I fly
> has them and the spread is minimal and lean of peak cruise is very
> smooth and economical. I don't have the spread at my fingertips here
> because I actually only monitor TIT during operation. JBB
>
> Jim Baker wrote:
>
>>--> Engines-List message posted by: "Jim Baker" <jlbaker@telepath.com>
>>
>>
>>
>>>That's one reason why the manufacturers eventually went to the
>>>mechanical fuel injection systems in use today. They can tune
>>>
>>>
>>each
>>
>>
>>>cylinder as if it were an individual engine and not worry about how
>>>the fuel is distributed. >
>>>
>>>
>>
>>
>>Well, that's partly true. FI is a whole lot better than carburetion in
>>terms of getting the right amount to each port.....avoiding having it
>>robbed from one port to someplace in the induction runner or to
>>another intake port is still a problem. I see about 125F difference
>>from top to bottom on my IO520. Unless you can do direct injection,
>>there's always some interference in the process at some given
>>RPM(s).
>>
>>
>>Jim Baker
>>580.788.2779
>>'71 SV, 492TC
>>Elmore City, OK
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>
>
>
Message 8
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| Subject: | Re: RE: 320-E2G sump question |
--> Engines-List message posted by: James Baldwin <jamesbaldwin@dc.rr.com>
Yes.
flyv35b wrote:
>--> Engines-List message posted by: "flyv35b" <flyv35b@ashcreekwireless.com>
>
>It's not the absolute EGT or even the difference from one cylinder to
>another that is the most important, but whether or not all cylinders reach
>peak EGT at close to the same time and mixture control position. Granted,
>this will change with throttle position and rpm and maybe other things but
>if the spread in fuel flow from the first cylinder to reach peak to the last
>is about .25 gph (on an IO-520 say) then you have a pretty even mixture
>distribution and the engine will run smooth on the lean side of peak EGT.
>You can have 2 different cylinders that are 50F or more apart temperature
>wise but reach peak EGT at the very same time. The GAMI injectors taylor
>the fuel flow to match the uneven airflow distribution and thereby hopefully
>have all cylinders reach peak EGT at close to the same time.
>
>Cliff
>----- Original Message -----
>From: "James Baldwin" <jamesbaldwin@dc.rr.com>
>To: <engines-list@matronics.com>
>Sent: Wednesday, February 15, 2006 4:55 PM
>Subject: Re: Engines-List: RE: 320-E2G sump question
>
>
>
>
>>--> Engines-List message posted by: James Baldwin <jamesbaldwin@dc.rr.com>
>>
>>Jim -
>>The Cont 520 series is well known for its air/fuel mixture distribution
>>problem. That of course is what the calibrated injector nozzles from
>>George Braly at GAMI are all about. Are you using the GAMI nozzles in
>>your airplane? The A36 with the Tornado Alley Turbo normalizer I fly
>>has them and the spread is minimal and lean of peak cruise is very
>>smooth and economical. I don't have the spread at my fingertips here
>>because I actually only monitor TIT during operation. JBB
>>
>>Jim Baker wrote:
>>
>>
>>
>>>--> Engines-List message posted by: "Jim Baker" <jlbaker@telepath.com>
>>>
>>>
>>>
>>>
>>>
>>>>That's one reason why the manufacturers eventually went to the
>>>>mechanical fuel injection systems in use today. They can tune
>>>>
>>>>
>>>>
>>>>
>>>each
>>>
>>>
>>>
>>>
>>>>cylinder as if it were an individual engine and not worry about how
>>>>the fuel is distributed. >
>>>>
>>>>
>>>>
>>>>
>>>Well, that's partly true. FI is a whole lot better than carburetion in
>>>terms of getting the right amount to each port.....avoiding having it
>>>robbed from one port to someplace in the induction runner or to
>>>another intake port is still a problem. I see about 125F difference
>>>
>>>
>>>from top to bottom on my IO520. Unless you can do direct injection,
>>
>>
>>>there's always some interference in the process at some given
>>>RPM(s).
>>>
>>>
>>>Jim Baker
>>>580.788.2779
>>>'71 SV, 492TC
>>>Elmore City, OK
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>>
>
>
>
>
>
>
>
>
>
Message 9
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| Subject: | Re: RE: 320-E2G sump question |
--> Engines-List message posted by: Dww0708@aol.com
sounds like pretty good scoop.... no irregularity intended David
Message 10
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| Subject: | Re: RE: 320-E2G sump question |
--> Engines-List message posted by: "Jim Baker" <jlbaker@telepath.com>
> That of course is what the calibrated injector
> nozzles from George Braly at GAMI are all about. Are you using
the
> GAMI nozzles in your airplane?
Well, that's the sad part. I live about 30 miles from Ada, OK and the
GAMI folks, have been over there several times watching installs
and test cell runs, but no, I don't because the cost/benefit for me
would be marginal.....except I really like the idea of LOP operation. A
GAMI install would first necessitate a JPI install as well. $$$$$
Sigh.....
Jim Baker
580.788.2779
'71 SV, 492TC
Elmore City, OK
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