Right on the money John!!!!!
Jeff R. N128LJ Gold Rush 912-S
On Jan 23, 2010, at 10:39 AM, teledynmcs@aol.com wrote:
> >>>>>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.
> 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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