Today's Message Index:
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1. 01:12 AM - Re: RE : Cylinder cooling issues - Guidance from Jabiru (Rob Turk)
2. 02:35 AM - Re: Cylinder cooling issues - Guidance from Jabiru (pat ladd)
3. 02:53 AM - Re: Cylinder cooling issues - Guidance from Jabiru (Rob Turk)
4. 03:55 AM - Re: Re: Coils (Kayberg@aol.com)
5. 06:38 AM - Re: RE : Cylinder cooling issues - Guidance from Jabiru (Andy Silvester)
6. 07:44 AM - Re: Re: Coils (Jim Crowder)
7. 07:49 AM - Re: Coils (TELEDYNMCS@aol.com)
8. 08:48 AM - Re: Re: Coils (Kayberg@aol.com)
9. 09:36 AM - Re: Coils (Andy Silvester)
Message 1
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| Subject: | Re: Cylinder cooling issues - Guidance from Jabiru |
6" pressure differential.. Hmmm, I'm starting to understand why Jabiru
included a vacuum pump pad in the design..
Rob
----- Original Message -----
From: Jim Crowder
To: jabiruengine-list@matronics.com
Sent: Wednesday, September 12, 2007 6:42 AM
Subject: RE: RE : JabiruEngine-List: Cylinder cooling issues -
Guidance from Jabiru
Andy Silvester
Suncoast Sportplanes Inc. writes:
"To avoid overheating problems of the Jabiru engines in non Jabiru
installations, it is vitally important that all installations provide a
greater that 6 inch of water, air pressure differential to provide
enough cooling for the Jabiru engine. Attached is a diagram of the tube
placements to measure this and photos. We are in the process of having
this included in the engine manual as a condition of warranty.
Attached is a diagram and photos that demonstrate how to perform this
test."
On slow moving aircraft this may be very difficult to achieve. I will
do my best on my Kitfox 5, but for those of us who have already
purchased our engines and paid for them, this is an unfair position for
Jabiru to take, and a warranty amended after purchase is likely
un-enforceable. The warranty at the time of purchase is a part of our
contract and cannot be amended unilaterally. Let new buyers beware!! I
want to be happy and will do my best to achieve the 6 inch of water
differential, but this does not feel good.
Jim Crowder
-----Original Message-----
From: owner-jabiruengine-list-server@matronics.com
[mailto:owner-jabiruengine-list-server@matronics.com]On Behalf Of
J=E9rme Delamare
Sent: Tuesday, September 11, 2007 1:58 PM
To: jabiruengine-list@matronics.com
Subject: RE : JabiruEngine-List: Cylinder cooling issues - Guidance
from Jabiru
Greater than 6 inch of water ! Sure ?
In my manual :" The required pressure drop across the cylinders at
1.3 Vs in take off configuration is 4.3 cm (1.7") water gauge, minimum."
To obtain a dynamic pressure of 6 inch of water you need an
Indicated Air Speed of 180 km/h (100 kts).
J=E9rme
Message 2
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| Subject: | Re: Cylinder cooling issues - Guidance from Jabiru |
By asking for optimal pressure drops, Jabiru is protecting itself against
warranty claims related to overheating.>>
Hi All,
this is my first posting to this list and it is obvious from lurking that
you guys are much more technically knowledgeable than I. On a scale of 1 to
10 put me in as zero.
I fly a Kolb Extra with a Jabiru pusher, in the UK. I have had little
experience as I managed to start the engine with the throttle wide open
after only a few hours flying . I hit a barn, and a parked car. The rebuild
has just been completed and I am waiting for Permission to Test Fly at the
moment.
I queried the rumours of Jabi`s overheating with the dealer when I ordered
the plane and he assured me that it was a thing of the past and more up to
date engines were OK. My engine must now be around 2 years old. Any
comments?
Cheers
Pat
Message 3
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| Subject: | Re: Cylinder cooling issues - Guidance from Jabiru |
Pat,
Jabiru has made several changes to the engine to improve cooling (more and
finer fins, new airducts), but a bad installation 8 years ago will continue
to be a bad installation today if nothing is done about it. As more Jabiru's
find their way to the skies, more experience will be built up and many
common mistakes early on will be known and corrected today.
Rob
----- Original Message -----
From: "pat ladd" <pj.ladd@btinternet.com>
Sent: Wednesday, September 12, 2007 11:35 AM
Subject: Re: JabiruEngine-List: Cylinder cooling issues - Guidance from
Jabiru
> <pj.ladd@btinternet.com>
>
> By asking for optimal pressure drops, Jabiru is protecting itself against
> warranty claims related to overheating.>>
>
> Hi All,
> this is my first posting to this list and it is obvious from lurking that
> you guys are much more technically knowledgeable than I. On a scale of 1
> to 10 put me in as zero.
> I fly a Kolb Extra with a Jabiru pusher, in the UK. I have had little
> experience as I managed to start the engine with the throttle wide open
> after only a few hours flying . I hit a barn, and a parked car. The
> rebuild has just been completed and I am waiting for Permission to Test
> Fly at the moment.
>
> I queried the rumours of Jabi`s overheating with the dealer when I ordered
> the plane and he assured me that it was a thing of the past and more up to
> date engines were OK. My engine must now be around 2 years old. Any
> comments?
>
> Cheers
>
> Pat
Message 4
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In a message dated 9/12/2007 12:27:04 AM Eastern Daylight Time,
jimlc@att.net writes:
"Jabiru haven't recognized any subsequent failures
and refer to the following facts:
1. Engines are dyno-tested at the factory and leave in fully working order.
2. Coils break-down in over heating conditions so they recommend in their
manuals for additional air cooling to the coils from the ram-air ducts."
And if they fail with the additional cooling? So much for honoring their
warranty! I'm not impressed.
Jim Crowder
As one who is in the warrantee service business in an unrelated product
field, I want to stick up for the manufacturer. I frequently see installations
that are well outside the factory perameters but the owners are quick to blame
the manufacturer. That is also happening in the Experimental Aircraft w
orld.
Airflow through a Jab engine is the key issue, from my experience. Do it
right one time and life is good. Use the recomended prop, shrouds, cooling
tubes, oil cooler and cowling exits and be rewarded. If you dont, I suggest
you be prepared to spend your own money on new parts.
People like to criticise manufacturers like Rotax and Jabiru when there are
problems, as tho the engines come with perpetual care. But much of the
complaining is undeserved, IMHO. The Jab importers bend over backwards to deal
with problems, it seems to me.
Doug
Message 5
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| Subject: | Re: RE : Cylinder cooling issues - Guidance from Jabiru |
I'm not sure if further explanation is needed on this latest cooling advice but
here goes anyway:
1. Jabiru engines get installed and operated in a huge variety of aircraft. The
only installations Jabiru can report and advise confidently on are (of course)
in their own aircraft. The efficiency of the cooling for the heads is as much
about the cowling design (extract, etc) as it is about the ram-air ducts provided.
What they've now done, through factory testing of different installations,
is come up with a set of measures for cowled-in installations which can be
replicated in the field and objective comparisons made with the advice. The cylinder
head cooling WILL be correct if the pressure differentials they specify
are met. This gets us past all the problems with different CHT measuring methods,
calibration of sensors, hot/cold junctions, etc. etc. If the pressure differential
is right, so will be the head temps.
2. The guidance is intended for those who are trying to reduce CHTs, either to
be within limits, or to bring the temps. down further from a normal-to-high situation.
My experience has shown that CHTs on all cylinders should stay below
300F, 150C in cruise, for good head life (to 1000 hours). Brief excursions above
these temps are OK when in the climb. Yes, the published upper cruise limit
is higher, but we know that heads (and compressions) last longer with the lower
CHTs. Temperatures of 220F, 105C should be achievable with the 6" pressure
differential mentioned. Cowling design, oil cooler location and relative airflow,
propeller choice, ambient air temps, type of fuel used, fuel / air ratio and
speed of aircraft all affect CHTs. As a dealer I can only advise based on experience;
Jabiru publish what they will and make the 'official' rules.
3. Warranty won't, and can't be retrospectively changed! The guidance is published
now for advice, but Jabiru have said that IN FUTURE the cooling requirements
and specification will be included as part of warranty. Quite honestly, how
we dealers are to ultimately prove or disprove this in warranty claims is beyond
me, but we'll see.....
4. So why is head temperature so connected to life of parts? We get feedback that
"Lycoming and Continental' have higher limits and don't have problems (yeah,
right). What you have in a Jabiru engine is a fine balance between power and
weight. To get the low weight there is obviously less material in heads (etc.)
and so heat build-up can get to the structure quicker than in heads weighing
twice as much or more (and they do). Also remember that CHTs are measured only
at one point on the head, and some parts of the head are much hotter (around
the exhaust port). When a Jabiru head is exposed to high temperatures which soak
through the entire structure, the aluminum can distort, both losing the bolt-torque
and hence head-to-cylinder seal, and also valve seats can start to move,
be drawn into the head material or simply twist around and lose valve seal.
Let's be clear - if the head temperature is kept within limits, and the lower
the better, it will last the course.
Andy Silvester
Suncoast Sportplanes Inc
--------
www.suncoastjabiru.com
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=134039#134039
Message 6
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Doug wrote:
People like to criticize manufacturers like Rotax and Jabiru when there are
problems, as tho the engines come with perpetual care. But much of the
complaining is undeserved, IMHO. The Jab importers bend over backwards to
deal with problems, it seems to me."
I have no complaint personally, but selling a product with a warranty and
then saying we tested it when produced and since it will fail if not
properly installed, then we consider any failure to be the fault of the
installation, is to say we do not warrant it. Parts can fail for other
reasons. In practice we may just need to show that we did install it
properly, or if we are lucky we may not ever need to test their
interpretation. However, what they are saying is not impressive.
For my part, I am forewarned and I plan to take extensive pictures of my
installation before even starting it up and of course I will take great
pains to do it right following to the best of my ability factory
instructions, as I am now doing.
Jim Crowder
-----Original Message-----
From: owner-jabiruengine-list-server@matronics.com
[mailto:owner-jabiruengine-list-server@matronics.com]On Behalf Of
Kayberg@aol.com
Sent: Wednesday, September 12, 2007 4:55 AM
To: jabiruengine-list@matronics.com
Subject: Re: JabiruEngine-List: Re: Coils
" In a message dated 9/12/2007 12:27:04 AM Eastern Daylight Time,
jimlc@att.net writes:
"Jabiru haven't recognized any subsequent failures
and refer to the following facts:
1. Engines are dyno-tested at the factory and leave in fully working
order.
2. Coils break-down in over heating conditions so they recommend in
their
manuals for additional air cooling to the coils from the ram-air ducts."
And if they fail with the additional cooling? So much for honoring
their warranty! I'm not impressed.
Jim Crowder
As one who is in the warrantee service business in an unrelated product
field, I want to stick up for the manufacturer. I frequently see
installations that are well outside the factory perameters but the owners
are quick to blame the manufacturer. That is also happening in the
Experimental Aircraft world.
Airflow through a Jab engine is the key issue, from my experience. Do it
right one time and life is good. Use the recomended prop, shrouds, cooling
tubes, oil cooler and cowling exits and be rewarded. If you dont, I
suggest you be prepared to spend your own money on new parts.
People like to criticise manufacturers like Rotax and Jabiru when there
are problems, as tho the engines come with perpetual care. But much of
the complaining is undeserved, IMHO. The Jab importers bend over backwards
to deal with problems, it seems to me.
Doug
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Message 7
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In a message dated 9/12/2007 2:58:52 AM Eastern Daylight Time,
jabiruengine-list@matronics.com writes:
OK, that's the 'Jabiru' line.
Hi Andy and all,
Just so everybody will know, I'm not in any way trying to slam you or
Suncoast. My previous comments were directed at Jabiru. Your support has been
excellent. Jabiru, on the other hand, leaves a bit to be desired. Thanks for your
generous offer of the $200 credit, but I won't be taking you up on that
because I don't think it's right for you to have to dig into your own pocket to
make up for a shortcoming of the factory. This issue is between me and Jabiru,
but I don't hold out much hope that they will make good on it and that will
certainly factor in to whether or not I purchase another Jabiru in the future
should the need arise.
I am surprised that Jabiru refuses to warranty my coils for two reasons.
One, the left coil was failed at the first start up. It was way out of spec on
the secondary side when measured with an ohm meter (Fluke 87) per Jabiru
instructions. This clearly wasn't my fault since I'd never run the engine before
the discovery of the failed coil. If this coil failed due to heat, it failed
when the factory did the initial run-in. My engine was installed per Jabiru
guidelines and the cooling tubes were installed from the head intake ducts to
the coils per Jabiru instructions. I have not noted any discoloration, checking
or any other signs that the coils were overheated.
Secondly, the second coil failed at about 30 hours. While this one could
have indeed failed due to engine heat, I don't think that is the case because
nothing has changed in my set up and the coils currently installed on the engine
have been there since 0 hours and 30 hours respectively. If there was a heat
issue in my setup these other coils would have also probably failed. One
has 107+ hours on it and the other has 77+ hours on it and the engine runs like
a top.
When I got the replacement coils, two from you and the other from Pete, (I
keep a spare on the shelf now just in case) they were considerably different
from the coils that came on the engine. The new coils were not only larger,
but had a different orientation of the coil wire where it exits the body of the
coil. They did appear to be from the same vendor, though. It seems clear to
me that Jabiru knew they had a problem with the original, smaller coils and
that prompted the change to the new, larger coil. I don't understand their
Rotaxian attitude, though. All I'm asking is for them to make good on the
warranty agreement they provided when I purchased my engine.
FWIW, I pretty much have my cooling issues under control on all but the
hottest days, and then I only see elevated temps in CHT's in climb on the left
side. I am sourcing a manometer and I'll do some measuring and see where I'm
at. My guess is I have adequate cooling flow, per Jabiru parameters already.
The real question is if I do indeed have adequate cooling flow, and I'm able to
prove it, will Jabiru make good on the failed coils?
I won't be a holdin' my breath on that one.....
Regards,
John Lawton
Whitwell, TN (TN89)
Europa N245E - Flying - 107 hours
Message 8
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In a message dated 9/12/2007 10:45:44 AM Eastern Daylight Time,
jimlc@att.net writes:
I have no complaint personally, but selling a product with a warranty and
then saying we tested it when produced and since it will fail if not properly
installed, then we consider any failure to be the fault of the installation,
is to say we do not warrant it. Parts can fail for other reasons. In
practice we may just need to show that we did install it properly, or if we are
lucky we may not ever need to test their interpretation. However, what they are
saying is not impressive.
For my part, I am forewarned and I plan to take extensive pictures of my
installation before even starting it up and of course I will take great pains
to
do it right following to the best of my ability factory instructions, as I
am now doing.
I think some distinction needs to be made between individual part defects
and damage caused by installation. In the case of the coils, if it can be
demonstrated that high temps fail the coils and at correct temps they last for
ever, then there is some probablility that if TWO coils fail immediatly on the
same engine, and the failure rate on that particular batch was very low; then
one should conclude that installation had something to do with it; ie high
temps.
It would then be up to the owner to justify how his installation DID NOT
cause high temps.
But another problem has to do with the age of the engine. Homebuilders
often buy their engines too early in the build and aging on the shelf causes
damage. That is why the warrantees to not start when the engine is first run.
That and other situations can cause failures that ARE NOT the factory's
problem.
I would just add that a good relationship with the dealer is essential for
good warrantee support. Some folks will try to save a few bucks by internet
shopping but lose the advantage of a friendly dealer. I know all the Jab
dealers in the USA and they are extremely helpful. They all seem to go the
extra mile to help a customer who asks for help.
Just an observation from experience: People in the service business cannot
resist someone who ASKS for their help , perhaps even begs. But customers
who try to dump all their emotions on a dealer and "DEMAND SATISFACTION" can
find themselves in a real pickle. Wether a passive-aggressive response or a
"pissed aggressive" response from a dealer, the result is biting the hand
that feeds you.
I think it is more important to have a dealer on your side than to do
exactly what a manual says. Manuals simply cannot contain all necessary wisdom.
Just a thought or two.
doug koenigsberg
Message 9
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All you guys are making sensible and valid points - thanks. I re-read my original
response about John's two coil failures and perhaps should clarify. There really
is no 'Jabiru Policy' about what, and what isn't agreed as a warranty replacement.
Yes, there is a warranty document which says that parts and labor are
warranted - and I think Jabiru's warranty which DOES start from first-run
and not the date of purchase is fairer than most. 'Obvious' mechanical failures
and breakages are of course warranted where there can be no question about the
way the failure occurred. However, people do overheat coils, which fail and
they claim under warranty. Similarly with overheating heads. Jabiru have seen
all these before and tend to be ready with a less than favorable answer, so for
us dealers, the onus is with us to go against the flow and 'prove' the operator
or installation wasn't at fault. In John's case I obviously didn't do a good
enough job providing the proof, because of course his were genuine warranty
issues. It was a while ago and I can't remember specifically, but I probably
caught the Jabiru factory guy on an off day or just after he's rejected someone
else's claim for free replacements - who knows?
What I'm saying is that ultimately, the decision on the replacement of parts which
could have been mis-used is both subjective and somewhat inconsistent. People
are involved in the decision process and so it's fallible. I'm not defending
or criticising necessarily - it's just the way it is. I'd be interested to
learn how any small company (Jabiru isn't Lycoming) can do it differently and
stay in business. They obviously can't honor every claim which is presented, because
a good number are due to abuse of the engine through poor installation.
John's claim is reasonable so I'll have another go at Jabiru with the hope of success
this time.
Andy Silvester
Suncoast Sportplanes Inc.
--------
www.suncoastjabiru.com
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=134065#134065
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