Today's Message Index:
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1. 06:06 AM - Re: 912 Exhaust Temp Question (Thom Riddle)
2. 07:32 AM - Re: 912 Exhaust Temp Question (ricklach)
3. 08:08 AM - Re: 912 Exhaust Temp Question (Roger Lee)
4. 08:32 AM - Re: 912 Exhaust Temp Question (lucien)
5. 04:06 PM - Re: Re: 912 Exhaust Temp Question (Dave Austin)
6. 04:39 PM - Re: Re: 912 Exhaust Temp Question (Joel M.)
7. 05:37 PM - Re: Re: 912 Exhaust Temp Question (Richard Girard)
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| Subject: | Re: 912 Exhaust Temp Question |
Knowing what the EGTs are doing during flight can lead to early detection of a
carb or intake problem.
My installation manual says
"nominal approx. 800C (1470F)
max. 850C (1560F)
max. 880C (1616F at take off
(readings of EFT taken approx. 100mm(3.93 in)from exhaust flange connections)."
--------
Thom Riddle
Buffalo, NY (9G0)
Kolb Slingshot SS-021
Jabiru 2200A #1574
Tennessee Prop 64x32
Everyone is entitled to his own opinion, but not his own facts.
Daniel Patrick Moynihan
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| Subject: | Re: 912 Exhaust Temp Question |
Joel I can not agree with you. Ive spent my life building engines and hundreds
of hours on a Dyno and you can change the exh-temps. Timing and carb mixture are
just two that can make a nice tuning difference in that area. On the other
hand the engine has 300-hours on it and it hasnt melted yet. But 1600 degrees
or higher is not right.
So, Roger, the exh-pipes were wrapped before I installed the temp probes. I just
drilled through the wrap and pipe, slipped in the prob along with some high-temp
silicon to form a seal and tightened then down with the hose clamp then come
with. If I under stand you correctly I should remove them, enlarge the hole
in the wrap so the probe can not touch the wrap and then reinstall them again.
Two questions:
1. Dose it matter that the clamp will be touching both the wrap and the probe?
2. I used red high-temp silicon to seal around the probe, do you think this could
be making a difference?
Thom, thanks for your numbers, appreciate more numbers if you guys have them.
Rick
--------
701Driver
N35 26.700, W118 16.743
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| Subject: | Re: 912 Exhaust Temp Question |
Hi Rick, (Hope this helps)
I sort of agree that many 912 users don't have digital EGT temp displays and many
don't have any EGT gauges and they fly and have never had an issue since 1990.
My sort of comment comes because I'm the analytical type and like info, but
unless you use the info you get in the correct manner it can be frustrating
at the least and cause you to damage your engine at the worst. If the engine is
maintained as per Rotax maint. and you don't mess with it it should never have
an EGT temp issue as the carbs and things are set from the factory. Remember
we don't care about an exact temp, but so long as it is within a range which
varies from the winter to summer months anyway. It also will vary with your airport
elevation and flying altitude. It will vary depending if you have a cowl
or not. It will vary depending on prop pitch and vary depending on the rpm you
cruise at. Midrange at 4700 will run hotter than 5100 rpm. Like I was saying
above, once you get all this info how do we interpret it. Yes seeing a temp
doing something that it shouldn't is worrisome, but you should use it only as
a single tool and correlate it with all the other info and engine running to make
it make sense or to see if the temp is lying to you or is real.
When I first put header wrap on my plane the EGT's went crazy and were not only
high, but would swing as much as 100F in a few seconds. So that's when I started
my little research project. Rick I would advise that you wrap the 2" between
the exhaust port and probe and use one clamp for that single piece. Then start
the wrap again on the other side of the probe. Use 2" wide wrap and only over
wrap each wind by about 3/8" and no more or it will retain too much heat.
The wrap should be slightly moistened when you apply it. I wrap all the way down
to the muffler and under the springs then put a clamp under the springs. This
will also help if you happen to get a little blow by gas at the knuckle. I
wouldn't let the clamps come in contact with the probe. If a single strand of
cut wrap touches the probe it doesn't seem to make a difference, but allow much
of the wrap to touch or cover it does make a difference. I have had header wrap
on my pipes from the exhaust port right down to the top of the muffler now
for 3.5 years and have not had a single issue and I know many 912 users that
have header wrap just like mine. It does make a difference on the temps inside
the cowl. The wrap Mfg. claims up to 70% heat reduction off the pipes. I don't
know if it's really that high, but when I land and pull the cowl I can grab
my exhaust pipe where as with out the wrap I'd be pulling my skin off. It does
help protect the wiring and any coolant or oil lines near by from radiated and
convective heat. I don't see any higher EGT temps with or with out the wrap.
I have a Dynon D120 EMS. Oh yes I forgot the silicone question. I don't personally
know of anyone that uses it. If the hole in the pipe was an exact fit for
the probe and you clamp it down it shouldn't be a problem.
I would worry more about odd temps if you are someone that doesn't maintain your
engine or likes to experiment and make changes on your Rotax engine different
from factory. The way it comes from the factory should be fine for most and
should have darn few exceptions.
--------
Roger Lee
Tucson, Az.
Light Sport Repairman - Maintenance Rated
Rotax Repair Center
Home 520-574-1080 TRY HOME FIRST
Cell 520349-7056
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| Subject: | Re: 912 Exhaust Temp Question |
Thom Riddle wrote:
> Knowing what the EGTs are doing during flight can lead to early detection of
a carb or intake problem.
>
> My installation manual says
> "nominal approx. 800C (1470F)
> max. 850C (1560F)
> max. 880C (1616F at take off
> (readings of EFT taken approx. 100mm(3.93 in)from exhaust flange connections)."
They can be good debugging tools also. I.e. right after I got my current plane
one of the carbs got plugged up due to a failed fuel line replacement job by yours
truly. Basically one side of the engine would starve of gas and shut down
as I approached full throttle.
Back at the ramp I could see which side was affected, the EGTs plummeted on that
cyl. bank as I opened it up and it do it's stumbling thing.
Another installation problem the plane initially had was the carby vent lines not
being put at the same atmospheric pressure as the intakes. I.e. they were just
run alongside the carbs on the outside. The EGT showed me the effects of that,
basically too cool at full power - 1100 to 1200F. Once I routed them into
the back of my airfilters I was able to see them get back up into a more normal
range, about 100F hotter (for my altitude anyway, the carbs seem to run a hair
rich at full power at my altitudes of 7000' MSL and above and the dangling
vent lines really show up as rich running up here).
They were useful for setting my idle mixture too. Like I said, I live at a high
altitude so the factory idle mixture of 1.5 turns on the screw is way too rich.
At first I didn't realize that 800 to 900F at idle was a symptom, until I kept
noticing my plugs getting fuel fouled at idle. But the EGT's helped me to
find the "peak" when I was setting my idle mixture so I could finally get it set
right (seems to idle best slightly rich of the peak idle EGT of about 1100F)
Like Roger says, you have to be able to interpret the info they're giving you or
you will end up in the rubber room if you concentrate on them too much. But
I still think they're worth installing if for no other reason than finding problems.
LS
--------
LS
Titan II SS
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| Subject: | Re: 912 Exhaust Temp Question |
Re the exhaust wrap, to change the subject just a bit..
My understanding is that the higher the stainless steel is heated, the faster it
will harden and
start the inevitable cracking process.
So why do you wrap ss exhaust pipes?
Dave 601HDS 912UL
Message 6
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| Subject: | Re: 912 Exhaust Temp Question |
Everyone has the freedom to do what ever they want and thats just fine.=C2
- I have over 2000 hours behind the 912uls and never had a EGT gauge.=C2
- If you leave everything alone and keep it the way it was setup at the f
actory it will last along time.=C2- Keep your oil temps and CHT in range
and it takes care of itself.=C2- If you keep the carbs in sync and do you
r regular maintenance and don't try to fix what isn't broken you will have
a trouble free running engine.
Joel
--- On Sun, 10/31/10, ricklach <rick@ravenaviation.us> wrote:
From: ricklach <rick@ravenaviation.us>
Subject: RotaxEngines-List: Re: 912 Exhaust Temp Question
Joel I can not agree with you. I=C3=A2=82=AC=84=A2ve spent my life bu
ilding engines and hundreds of hours on a Dyno and you can change the exh-t
emps. Timing and carb mixture are just two that can make a nice tuning diff
erence in that area. On the other hand the engine has 300-hours on it and i
t hasn=C3=A2=82=AC=84=A2t melted yet. But 1600 degrees or higher is n
ot right.
So, Roger, the exh-pipes were wrapped before I installed the temp probes. I
just drilled through the wrap and pipe, slipped in the prob along with som
e high-temp silicon to form a seal and tightened then down with the hose cl
amp then come with. If I under stand you correctly I should remove them, en
large the hole in the wrap so the probe can not touch the wrap and then rei
nstall them again. Two questions:
1.=C2-=C2-=C2- Dose it matter that the clamp will be touching both th
e wrap and the probe?=C2-
2.=C2-=C2-=C2- I used red high-temp silicon to seal around the probe,
do you think this could be making a difference?
Thom, thanks for your numbers, appreciate more numbers if you guys have the
m.
Rick
--------
701Driver
N35 26.700,=C2- W118 16.743
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=317574#317574
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List
S WEB FORUMS -
on Web Site -
=C2- =C2- =C2- =C2- =C2- -Matt Dralle, List Admin.
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| Subject: | Re: 912 Exhaust Temp Question |
Joel, all, One thing an EGT gauge will tell you is if you get an air leak i
n
the carb boot. There was a batch of bad boots made in the mid oughts that
were pretty much failed as they left the factory and started to crack
through long before normal expectations of the 200 hour check. To make a
long story short, rising EGT's alerted me to something amiss and I found th
e
cracks before I had engine damage.
Whether E-AB or E-LSA, they are all individual experiments and should be
conducted accordingly. I believe an EGT is cheap insurance, but that's my
decision.
Rick Girard
On Sun, Oct 31, 2010 at 6:35 PM, Joel M. <dirtfly7@yahoo.com> wrote:
> Everyone has the freedom to do what ever they want and thats just fine.
I
> have over 2000 hours behind the 912uls and never had a EGT gauge. If you
> leave everything alone and keep it the way it was setup at the factory it
> will last along time. Keep your oil temps and CHT in range and it takes
> care of itself. If you keep the carbs in sync and do your regular
> maintenance and don't try to fix what isn't broken you will have a troubl
e
> free running engine.
> Joel
>
> --- On *Sun, 10/31/10, ricklach <rick@ravenaviation.us>* wrote:
>
>
> From: ricklach <rick@ravenaviation.us>
> Subject: RotaxEngines-List: Re: 912 Exhaust Temp Question
> To: rotaxengines-list@matronics.com
> Date: Sunday, October 31, 2010, 8:29 AM
>
s<http://mc/compose?to=rick@ravenaviation.us>
> >
>
> Joel I can not agree with you. I=99ve spent my life building engine
s and
> hundreds of hours on a Dyno and you can change the exh-temps. Timing and
> carb mixture are just two that can make a nice tuning difference in that
> area. On the other hand the engine has 300-hours on it and it hasn
=99t
> melted yet. But 1600 degrees or higher is not right.
>
> So, Roger, the exh-pipes were wrapped before I installed the temp probes.
I
> just drilled through the wrap and pipe, slipped in the prob along with so
me
> high-temp silicon to form a seal and tightened then down with the hose cl
amp
> then come with. If I under stand you correctly I should remove them, enla
rge
> the hole in the wrap so the probe can not touch the wrap and then reinsta
ll
> them again. Two questions:
>
> 1. Dose it matter that the clamp will be touching both the wrap and th
e
> probe?
> 2. I used red high-temp silicon to seal around the probe, do you think
> this could be making a difference?
>
> Thom, thanks for your numbers, appreciate more numbers if you guys have
> them.
>
> Rick
>
> --------
> 701Driver
> N35 26.700, W118 16.743
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewto; -->
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atronics.com/Navigator?RotaxEngines;
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--
Zulu Delta
Kolb Mk IIIC
582 Gray head
4.00 C gearbox
3 blade WD
Thanks, Homer GBYM
It is not bigotry to be certain we are right; but it is bigotry to be unabl
e
to imagine how we might possibly have gone wrong.
- G.K. Chesterton
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