Replies to This Discussion

Permalink Reply by John Austin on July 11, 2020 at 6:30am

The engine forums are a relatively new addition and I don't think this topic has been discussed.  I am aware of a service bulletin from Jabiru Australia that gives guidance on through-bolt replacement, but there are a lot of criteria such as serial number and whether it was used for flight training, etc. (Jabiru is a very popular engine/aircraft in flight schools in Australia.)  This all came out as a result of a CASA study (Australia's version of the FAA) on Jabiru engine failures.  Later analysis of the study found it to be deeply flawed, including counting incidents such as a student pilot getting lost and running out of fuel as "engine failure!"  Last time I checked, there were no engines in existence that continue to run with no fuel!  Ha!

Curiously, the US experience has been not even remotely similar to the supposed Australian experience according to  Pete Krotje who used to manage Jabiru USA in Shelbyville. Through-bolt problems, flywheel problems, etc. were almost non-existent at his repair facility and since they supplied parts for repairs elsewhere in the US, he didn't see reports elsewhere, either.

Perhaps someone in the US who has been there/done that can chime-in as to through-bolt replacement cost and complexity, etc., but you are correct that the Jabiru repair facility in the US is in Shelbyville, TN.  Pete has retired and Arion Aircraft is the repair facility and US distributor for Jabiru engines and parts.  I'd talk to Nick Otterback, the manager, and get his opinion on whether through-bolt replacement is really necessary and of course he can give you an estimate.

I'm sure the members would be very interested if you'd relay what you find out.

John

N750A

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Permalink Reply by Don Burkholder on July 11, 2020 at 9:05am

Yes John, the Australian fuel quality was also an issue with detonation. Not good for through bolts!! I remember that there was a time period of engine hours that replacing just the rod nuts was a great improvement as the factory nuts had a sloppy class of fit. The factory nuts were not as tall, (length of thread engagement), also. I ordered nuts from Pete K. that turned out to be 3/8" fine thread high strength flanged nuts similar to, if not actually from, a company called ARP. ARP, Automotive Racing Products makes excellent hardware for race engines here in America and I have been using ARP for years on all my race engines.These nuts are flanged on the bottom, taller for full thread engagement and have a much better, tighter class of fit. There is a bulletin from Jabiru website on this specific procedure of nut replacement and or 7/16" rod replacement relating to engine hours left till overhaul. I'm going by memory here so.......

  The job of replacing nuts is not bad but tight clearances to access the sloppy factory nuts, (6 point nuts) for removal and then replacement with new 12 point high strength nuts require the purchase of a 12 point swivel socket. A standard 12 point socket and extension will not work! SnapOn has this swivel socket, or even older Craftsman will do but it must be short in depth of socket. I chased a SnapOn truck to it's next stop and made the purchase! Do only one through bolt at a time! Replace the nuts on both ends and torque to specs, (I don't remember). Then go on to next through bolt..

Here is a, way too big picture of my 2200. The idea was to show the 12 point flange nuts when you zoom in...  Mechanic, yes. Computer tech, NO!................. Hope this helps..

Email, burdon1@comcast.net

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Permalink Reply by Ernest Jessee on July 12, 2020 at 2:52am

John and Don,

Thank you for responding.  It's a shame that flawed data or misinterpretation of data can ruin the reputation of a very good engine. The engine I am looking to purchase had the 12 point nuts installed in 2013, fairly soon after the bulletin was published.  I think i am reading that neither of you has replaced your through bolts. 

Since Australian fuel quality seems to have been a factor in Australian failures, burning 100LL would probably be wise in the JAB33. The current owner of "my plane' says he only burns 100LL.

Thank you for responding.

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Permalink Reply by John Austin on July 12, 2020 at 6:51am

I did not need to replace my through-bolts as my engine, #2427, was built well after the JSB031-2 service bulletin came out and is not in the range of applicable serial numbers - it has the 7/16" through-bolts and nuts.  I don't routinely run 100LL - in fact, I avoid it as the lead creates a lot of deposits!  Jabiru approves 90 AKI auto fuel and I use 93 AKI auto fuel that does not contain ethanol.  Has worked great for about 600+ hours!

John

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Permalink Reply by Ernest Jessee on August 17, 2020 at 7:33am

Thanks John,  I am glad to hear that you have had good luck with ethanol free mogas.  I have a source for 90AKI which is, as you state, approved.  It's much cheaper and I also hope will avoid lead deposits.

Since I started this thread, I bought the plane.  I flew her from Philadelphia to Raleigh and have flown her several hours since.  She uses no oil and hasn't had a single squawk.  I'm thrilled. So far, it seems like a fantastic engine.

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Permalink Reply by Bob Johnson on July 12, 2020 at 1:32am

The most active forum for Jabiru engines (and the now-defunct Camit second-source) is the groups.io forum: JabCamit

You might want to search that forum, or sign up and ask your question there.

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Permalink Reply by Ernest Jessee on July 12, 2020 at 2:52am

Thank you Bob. I have joined the forum on groups.io.

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Permalink Reply by John Austin on July 12, 2020 at 7:16am

I've been a long-time follower of that group and it's Yahoo predecessor, but one caution - you'll soon learn the majority of the posts are from a small group of people that are really into experimenting and modifying their engines.  IMHO some of their occasional problems with their engines are of their own making with their experiments - and some of the "problems" are more technical than a practical concern.  Don't get me wrong, I have found valuable information there, but as in all forums, consider the source!  I am prone to modify and tinker with the accessories, etc. on my engine, but when it gets to the deep internals, I subscribe to the Mike Busch philosophy that unnecessarily tearing down engine assemblies, etc., probably does a lot more harm than good.

John

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