Hi John,
> It might behoove you to take a look at the Rotax Service Instruction
> on the 912 that came out last March (2009) regarding oil changes.
> Specifically, SI-912-10R3 dated March 19, 2009. This SI runs
> concurrent with SI 912-018 entitled "Purging of Lubrication System" In
> SI 912-018, it specifically describes how to purge the oil system when
> changing the oil in a 912/914 to remove old oil and then how to
> rebleed the system with new oil. Doing this procedures ensures that
> the journals, bearings, rocker arms, etc are all properly lubricated
> prior to start up after the oil change. SI 912-010 R3 reiterates this
> method because so many Rotax 912/914 owners have not been following
> the proper oil change procedure and bearing failures, among other
> things, have resulted. Kerry down at Lockwood in Florida told me that
> if you aren't doing this procedure "you are asking for
> trouble". There is a similar SI issued for the 914 with the same
> date. Some people refer to this procedure as "burping the engine"
> because of the noise it makes when you are purging.
There is some confusion, here. "Burping" the engine is turning it by
hand to ensure all oil is back into the tank before checking the oil
level. I'm used to doing that -albeit for other reasons- on any engine
that has not run for some period of time.
Purging the circuit is something else : it is what is called "preoiling"
by some other manufacturers. One should do that on ANY engine after
draining the internal oil circuit or reassembly.
The hydraulic lifters are not a panacea, and they are very susceptible
to air pockets on start. The Jabiru lifters are no exception. I'll
suggest you preoil -or purge- your oil circuit any time you remove
significant parts of your engine, whatever the brand.
> You can simply drain the oil from the tank, change the filter and
> refill with new oil, but you are leaving nearly a quart of old oil in
> the engine and lines if you do it that way. I'm not that familiar with
> the 912/914 configuration as it exists in the Europa, but that is
> nearly 1/3rd of the oil in my Ximango 912S oil system. Leaving 1/3rd
> of tht old oil in the lines and engine kind of defeats the purpose of
> doing an oil change, doesn't it?
Every owner is entitled to do something else than what the SBs, SIs and
manuals say if he wants so. But I would suggest you just operate the
engine as per the book unless you have access to a considerable engine
knowledge based on hands-on experience and thorough measurements.
As for myself, I do run and maintain Rotax engines per the manuals and
manufacturer's instructions with very good results.
>
> >>>>>Any serious engine manufacturer SHOULD issue dozens of SBs, SLs,
> etc...<<<<<
>
> The Jabiru engine continues to be refined, just like the Rotax 912/914
> and it has proven to be at least as reliable as the Rotax, if not more
> so because it is so simple, but, as with any aircraft engine you have
> to tune it for your airframe for best results.
There are too few Jabiru engines in my country as compared to Rotax to
support any valid comparison.
> The Jabiru is built like a tank compared to the 912/914
That's your opinion, sir, and you are entitled to it.
> , or more appropriately, built like a Lycoming, Franklin or
> Continental. Compare that to the three crank support bearings in the
> Rotax 912/914, coupled to high compression pistons and an engine that
> isn't all that well balanced and ????. This weak support of the
> crank is directly related to the high number of crank and
> case failures that have happened with the 912/914. Rotax also had a
> bad run of cranks out for a while about 10 years ago. One guy who used
> to keep a 914 powered Katana motorglider at my field had one.
That's one failure, sir.
The spate of broken crankshafts you are referring to is unheard of in my
area.
I won't enter any Rotax vs Jabiru dispute based on "crankshaft better
support" or "built like a tank" arguments, because what makes engines
last is engineering, not opinions.
What counts is you're happy with your engine.
As for myself, I always do everything I can to learn more on any engine
before expressing an opinion. Especially when a "high number ...of
failures" is referred to.
Best regards,
--
Gilles
http://contrails.free.fr
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