>>>>>Jabiru is not a good solution! I know many engines for sales in
France replaced
by Rotax. <<Reliability>><<<<<
Greetings Team,
Once again, someone repeats negative rumors about the Jabiru 3300 without
actual, hands on Jabiru experience. This happens virtually every time
someone mentions a Jabiru engine on this forum and it's gone beyond being very
tiresome and has crossed into vague, rumored bullshit.
What specifically were the problems you cite that caused the Jabiru engines
you speak of to be unreliable and replaced with Rotaxs? Please elaborate.
A little more info, rather than a broad, sweeping indictment and
condemnation of Jabiru would be far more helpful. I personally know first hand
of
three Rotax 914's that have sustained broken cranks due to turbo over boost
situations when the turbo waste gate stuck shut. I've also seen Rotax 912's
with cracked cylinders, cracked and/or fretted cases, cracked exhaust, and
spun main bearings due to improper oil purging during oil changes and I've
heard second hand about a lot more issues. Anyone with a decent set of
eyes can see that the Rotax is far, far more complicated than the Jabiru. For
years now, right here on this very forum, I've read again and again of the
trials and tribulations of Europaphiles and their various troubles with
Rotax engines. Would it be fair for me to say that all Rotax engines are crap
based on these events and forum posts? Of course not! It all boils down to
how each engine is operated.
Some of the early Jabiru engines had reliability issues, mostly due to
inadequate cooling because the cooling fins on the cylinder heads were too
small. That is well known and the problems associated with that issue have
been corrected. There was also a problem with the bolts fretting and breaking
that attach the flywheel, but that has been narrowed down to engines that
had sustained unreported prop strikes. This issue has likewise been
corrected by installing pins between the flywheel and the crank in newer
engines
and replacing the flywheel bolts with stronger bolts and tighter torque on
older engines. Similarly, although it's been a bit longer since the Rotax
debuted and many who are new or relatively new to sport aviation may not
remember or be aware, but many of the early Rotax 912/914 engines also had
serious reliability issues. Read through the Rotax published SB's and AD's and
familiarize yourself with the issues that have plagued the Rotax 912/914
series engines over the years before you bash Jabiru outright. Some of that
stuff will curl your hair and make you think the Rotax 912/914 isn't suitable
for use on a lawn mower. Why do you think there are dozens of Rotax
Service Directives to comply with? Hint: it's not because the Rotax's were
reliable in the early days of production!
In fact, the 912/914 still has reliability issues if not properly taken
care of and Jabiru, Lycoming, Continental, Franklin, Subaru, Limbach, et al,
are no different. Dozens, if not hundreds, of posts have been put up right
here on this forum covering a wide range of reliability issues with the
Rotax 912/914. These include, but are not limited to, engine cooling, carb
issues, turbo issues, leaks, slipper clutch and redrive issues and ignition
issues. You simply cannot run either of these engines with the wrong oil or
improper cooling or the wrong prop loading or improper maintenance and
expect a high degree of reliability. It just won't happen.
Just because the manufacturer's name is Rotax does not instantly mean
bullet proof. Quite the contrary. Likewise, just because the manufacturer's
name is Jabiru doesn't mean it's unreliable, but that theme seems to get
repeated here adnauseum. This notion that overall the Jabiru 3300 engine is
unreliable is a pure and unadulterated myth that continues to be repeated again
and again here on this forum with little or nothing of substance to back
up the claim. I personally know several dozen Jabiru owners who could not be
happier with their engines, myself included. A while back the Jabiru 3300
with hydraulic lifters passed JAR certification. Unreliable? Funny, the JAR
didn't seem to think so!
I have admitted I had some initial problems getting my CHT's to run cool,
but that was my fault for not understanding how to make the head cooling
work. I was blazing a new trail insofar as the cowl set and head ducts I was
using and, at the time, there were only a handful of Europas flying with
Jabiru engines installed. So, it stands to reason that, with little guidance,
I would have some problems until I educated myself and got it all sorted
out. That's why they call these things "experimental", right? I also had
high EGT's initially, but again, that was my fault for not fully
understanding the relationship between airframe drag, carb tuning, prop pitch
and
EGT's.
The Jabiru engine comes from the factory tuned specifically for the Jabiru
airframe. If you hang a stock Jabiru engine on a much cleaner airframe,
like a Europa, it presents less load to the engine throughout the RPM range
and the result is the engine runs leaner. If this situation isn't corrected,
you will have reliability issues, i.e., hotter EGT's and CHT's, burnt
exhaust valves, etc. If you hang a stock Jabiru engine on a drag queen, like a
CH701 or something similar, the load presented to the engine is greater
and results in a richer running engine and reliability issues will result if
not corrected, i.e., flooding, fouled plugs, etc.
Each operator/builder must carefully choose (or tune) the prop and tune
the carb for your specific airframe in order to keep the engine happy and
within approved operating parameters. You must also make sure that the heads
get adequate cooling flow. Like purging the oil system on a Rotax with every
oil change, this tuning is just something you have to do in order to make
a Jabiru work properly in your airplane. In this incidence reliability has
far more to do with the carburetor tuning and prop pitch as it relates to
airframe drag than it does the engine itself. If you don't adjust the tuning
to suit your airframe, yes, you are going to have problems, but is that
Jabiru's fault? Hardly. Jabiru tells you exactly how to do it and if the
owner doesn't comply it isn't Jabiru's fault. Period.
Graham, in regard to the intake plenum and turbulated flow entering the
carb, I think you have it exactly backwards, at least insofar as the
Jabiru/Bing set up is concerned and what I have learned from my own experience
with
this engine. I have a smooth bore radiator hose with a 90 degree bend that
ducts air from my air filter box mounted on the firewall down and into the
Bing carby on the back of the Jabiru. Initially, I had gross unevenness in
my EGT's across the RPM range. I installed a vane (+) inside the intake
plenum just up stream from the carby made from .025" stainless sheet to
smooth out the airflow before it entered the carb. My EGT's went from a 200F
hottest to coolest, to a spread down to about 50F just by installing this vane
with no other change made. The airflow entering the Jabiru intake splitter
downstream of the carb must be smooth in order to have even distribution
of the fuel/air mixture to all cylinders. Turbulated air flow results in
uneven EGT's.
It is also crucial that the prop be properly tuned (if adjustable) or
chosen specifically for climb and cruise parameters (EGT vs RPM) for the
airframe in order to achieve acceptable EGT's. By lowering the EGT's you also
will affect the CHT's. Jabiru has published Service Bulletins on how to do
this. Jabiru USA in Shelbyville offers a great 3 day course on the Jabiru
engine that covers this topic in great depth. These guys really have this
figured out. I highly recommend anyone considering this engine take this
course.
The knowledge you will gain is worth every penny of the $300 entry fee.
Because Jabiru uses the Bing carb the 2200 and 3300 both are sensitive to
prop and airframe loading, as well as carburetor tuning (jetting).
Personally, I would love to see someone develop direct fuel injection for this
engine. I tried a Rotec TBI, but I couldn't make it fit because of a conflict
with the engine mounts. Some Jabiru owners, primarily Sonex builders, are
using the Aerocarb, but there have been numerous problems reported with it. The
Bing is basically a motorcycle carb and doesn't lend itself very well to
this application unless properly tuned and even then it has shortcomings.
The 3300 is a powerful little engine. It's simple and robustly built, far
simpler and more robust that the Rotax. I've seen first hand how both
engines are built internally. For incidence, the Jabiru has main bearings
between each con rod on the crank, not just on the ends and in the middle like
a
Rotax 912/914. The crank in the Jabiru is much better supported than the
crank in the 912/914. A quick peek inside each engine and seeing how they are
built won't leave you with a lot of confidence in the robustness of the
Rotax, that is for sure. The parts for the Jabiru overall are cheaper, and
many commonly replaceable parts are available at auto parts stores over the
counter. If properly tuned and maintained, there is absolutely no reason why
the Jabiru shouldn't be a very reliable engine in any airframe and a lot
cheaper to operate than the Rotax, but you have to adjust the tuning to
match your airframe combination in order to make it work.
I'm very pleased with my Jabiru, especially now that I have been through
the Jabiru engine course and I fully understand how the engine is built, how
the Bing carby operates and how to tune it and the prop for airframe drag
(or lack thereof). My Europa is a trigear. I'm running a Sensenich carbon
ground adjustable prop. I do not have straight pipes, but I do have the
newer 3 into 1 exhaust manifold arrangement with an expansion chamber (muffler)
and a single exhaust stack. I see climb rates solo a bit over 1800 fpm and
1400 fpm with two on board with full fuel and full baggage. I cruise at
128-130 kts at 5 gph. Top speed at WOT is a bit over 160 kts indicated, all
for $12,000 less than the Rotax.
FWIW, just so everyone will know that I have nothing against Rotax. As I
have mentioned here before I also own an Aeromot Ximango AMT200S
motorglider. My Ximango has a certified 912S installed. I compare the Jabiru
3300
to
the Rotax 912S on an almost daily basis (except now because it's January and
the weather is crap). I've been comparing these engines directly from both
an operational and maintenance standpoint for nearly three years now. I
cannot see any distinct advantage of the Rotax over the Jabiru or vice versa
in these direct comparisons. Several things I have noticed are worth
mentioning, though.
The Rotax engines are very expensive for those of us on this side of the
pond with the current exchange rate. Likewise, Rotax parts, when compared to
Jabiru parts, are definitely more expensive, much more expensive. Oil
changes with the Rotax are a pain in the ass compared to changing the oil in
the Jabiru. The Rotax is a far, far more complicated engine when compared to
the Jabiru. If you believe in the K.I.S.S. principle for aviation related
components, this bodes well for the Jabiru. The Rotax is probably a better
choice for my motorglider because the wet heads help slow the engine
cooling, avoiding shock cooling, when I shut the engine down to soar after
climbing to usable lift. There is no second carburetor on the Jabiru to keep in
sync as with the Rotax. With the Jabiru, set it and forget it. The Jabiru has
fixed timing with simple, dual distributors, as opposed to an $800
ignition module that will leave you stranded if and when it fails. My 3300 is
a
solid lifter version and I do have to torque the heads and keep the valve
tappet clearance adjusted regularly. I time that maintenance with my oil
changes and can easily torque the heads and adjust the valves while the oil is
draining with time to spare. Otherwise, I'm really enjoying the extra 30 or
so HP that the Jabiru offers my Europa over the 912S. I also like the
throaty, real airplane engine sound of the Jabiru over the whiny noise the
Rotax makes. The Jabiru is also a far, far smoother running engine with MUCH
less vibration than the Rotax. I say this not only from a pilot feel
standpoint, but also because I've had both props balanced using an ACER
Probalancer. Interestingly, my Jabiru needed no further adjustments to achieve
perfect
balance. The Rotax required some counter weights to balance the prop.
So, with all this said, enough already with this second hand Jabiru
bashing. If you have specific, first hand experience with issues regarding the
Jabiru 3300, let's hear 'em and we'll talk about it. Broad based condemnation
of either engine is useless to everyone and only fuels the rumor mill.
IMHO, the Jabiru 3300 is a fine little engine and if I had it to do all over
again I would indeed buy another Jabiru for my Europa. My experience and
the experiences related to me by the fine folks at Jabiru USA and Lightning
Aircraft in Shelbyville, TN, show that, more often than not, it is the
operators that have the problem because they aren't tuning the prop and carb to
suit their airframes or they are running the wrong oil or they are allowing
the engine to run hot, or otherwise abusing or not properly maintaining
the engine. I can cite literally dozens of failures in Rotax's that have
resulted from the same sort of abuse if you'd like, but you can learn about
them yourself by reading through the Rotax SB's and AD's.
BTW, anyone who is interested please note that my email is changing at the
end of the month. My new email will be _wingdingy@gmail.com_
(mailto:wingdingy@gmail.com) . This address is up and running now. Sorry for
the
inconvenience.
Regards,
John Lawton
Whitwell, TN (TN89)
N245E - Flying and lovin' every minute of it!
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