Jabiru Engine 2200 Mechanical Problem Reporting

[rick-p]

Nev you will recall that some time ago I had an oil pressure problem with my Jab 2200, it is now fixed.

 

I installed an oil cooler to the rear of the motor with cooling ducting directed from the top of the cowl.

 

All works perfectly now.

 

It must have been heat layering of the oil that wasn't being picked up on the probe but causing the drop in pressure as apposed to an unacceptable rise in temperature on the guage.

 

The moral of the story is that notwithstanding the fact that the engine is operating suposedly OK elsewhere in the same type aircraft the interveneing factors where you are operating from may well be sufficient, although only suttle, to change the position of the goal posts.

 

Jabiru did advise me that they wouldn't warrant the engine unless it had an oil cooler installed.

 

It hasn't upset my hot box for carby heat, in fact I think that it has complimented it.

 

The Jab's running in Lambada's in Ireland and Europe must because of the climate, much cooler weather, offset some of the oil cooling problems with layered oil heat.

 

The plane was purchase by me from a guy on the otherside of Sydney where there is much cooler summer temperatures than here, he had no problems these only commenced in the much hotter climate where I play.

 

The X-Air's flying in the Philippines with Jab 2200's because of no cowl must have some of the layered oil heat disapated by the cool air flowing around and over the whole motor.

 

This is probably evidenced by the fact that they tape up their oil coolers as the engines otherwise don't reach operating temperature.

 

Anyway the bonus moral of the story is listen to the engine manufacture as even if they can't pinpoint the problem exactly they can always offer a fix within the range.

 

Also you and guys like Brent through this forum offered some very valuable advice as to the possibilities in respect of the problem and for this I say thankyou.

 

Rick-p

 

 

[RKW]

The saga continues....

 

After about 300 hours of use, the thru-bolts decided to shed their nuts again! With rough running and almost total power loss on take-off at 400 ft, the instructor skillfully landed on the short runway last Saturday morning. Took the engine to Bundaberg on monday and awaiting their report. Now have a new engine with the latest specs (hollow pushrods etc) The thru-bolts need to be high tensile with rolled threads instead of machined chrome molly. Atleast that might keep the two halves together! There were numerous reports of thru-bolt failure in the Sept Oct Flight Safety Mag. The folks at Bundi were unaware of this. Anyway I will keep those who are interested posted if and when further info comes to hand. Regards, Bob

 

 

[Guernsey]

Little response from members visiting this forum

 

Hi Guys,

 

There could well be several people incuding myself who are considering

 

purchasing a J200, hence the interest.

 

 

[Tomo]

After about 300 hours of use, the thru-bolts decided to shed their nuts again! With rough running and almost total power loss on take-off at 400 ft, the instructor skillfully landed on the short runway last Saturday morning. Took the engine to Bundaberg on monday and awaiting their report. Now have a new engine with the latest specs (hollow pushrods etc) The thru-bolts need to be high tensile with rolled threads instead of machined chrome molly. Atleast that might keep the two halves together! There were numerous reports of thru-bolt failure in the Sept Oct Flight Safety Mag. The folks at Bundi were unaware of this. Anyway I will keep those who are interested posted if and when further info comes to hand. Regards, Bob

Yes, very interesting indeed. As you already know, I was there when Bill made the emergency landing, and I had a look out the motor on the floor once you got it out.

 

Too me everything looked perfect except the stud they use, and it seems to me that it is mostly the bottom ones that let go. Interesting again.

 

I wonder how hard it would be to up grade to something say 3/8 or 7/16th in stud size. (not sure what they have there now, but it looked like 5/16??) Also getting a rolled stud would be ideal.

 

To me it seems an easy fix, I wonder how much it would take to alter the certification. Probably be a night mare, as it is changing the actual structure of the engine.

 

Pity really.

 

 

[Vev]

Hi Bob,

 

Sorry to hear about your engine letting go.

 

Jab claim the thru bolt failures are mostly caused by detonation .. to that end they have been slowly reducing the compression ratio over the past couple of years. The very latest engines now have either a 0.5mm spacer under the cylinder or a 0.5mm longer cylinder to pull back the compression ratio. The lower comp and better cooling with the more fins and a richer jetting in the Bing should all help reduce the detonation, so long as you are all using the right octane fuel too.

 

By the way ... what fuel was that broken engine running?

 

Cheers

 

Jack

 

 

[Guest Nelson Smith]

Hi Rick-p

 

2200 did 987 hrs without any problems.Have now changed to the latest engine and it is going real well.

 

This survey will be flawed if flying school hours are'nt raken into account.

 

Nelson

 

 

[Guest Pioneer200]

In GA flying the engine etc are only meant to be looked after by a LAME who has been trained to do the work needed.

 

I would be interested to see if many with Jab 2200 engines get them ONLY serviced by a LAME who has all the service bulletins at hand and does ALL the maintenance when and in the hour frame that is required.And do these engines give better service???

 

Is it the engines that are privatly owned and worked on by UNTRAINED people that give the problems.

 

Cheers

 

When you fly behind a 2200 you tend to watch these treads with great interest:cool:

 

 

[RKW]

Hello Jack,

 

The broken engine has always been run on 100LL. I think the new motor has been built to the latest specs. It has no external oil feed to the rockers. Best Regards, Bob

 

 

[RKW]

Hello Blackrod, I, too found it amazing that they were unaware of the Flight Safety reports on the thru-bolts. Who is looking out for us? We left them with a copy of the Flight safety Mag! Best Regards, Bob

 

 

[dazza 38]

A bit off thread, but there is a SDR for a J230DL with 19 hours TSN.Broken trim cable.Nov-Dec Flight Safety. I wonder if the factory knows about that one yet?

 

 

[Old Koreelah]

Augmented exhaust

 

My two bob's worth: I have a hydraulic 2.2 in my little Jodel D9. I experimented with augmented exhausts and have found the cooling excellent, even with tiny intakes. If it gets too warm in summer I can easily enlarge the intake area.

 

All engine gasses exit into the low pressure area above the wing leading edge. The suction created in flight is considerable, but even on the ground the CHT's and oil temps are acceptable. I did find that the trumpet-shaped ejector raised exhaust noise to uncomfortable levels. I then removed the mixer and ejector assemblies, saving 3kg. The howl is now gone and I found the reduction in thrust to be only about 3%.

 

http://naca.central.cranfield.ac.uk/reports/1945/naca-report-818.pdf

 

One advantage of this old design is the reduced risk of shock cooling.

 

 

[Yenn]

It is amuzing to see the quick off the cuff replies to problems such as this one.

 

Will changing the size of a bolt to a larger one really prevent breakages? If a bolt breaks we need to know why, rather than up the size. For a bolt to work properly, it must be either well and truly oversize, or be torqued up correctly.

 

If the bolt is under torqued, it will not be loaded enough to stretch it, that means the parts can move and cause fretting. if the bolt is overtorqued it can fail disastrously. Increase the bolt size and you increase the torque, now you are overcompressing the components, which in the case of a Jab engine are aluminium and can also cause problems.

 

 

[wizzard1964]

.. to that end they have been slowly reducing the compression ratio over the past couple of years. The very latest engines now have either a 0.5mm spacer under the cylinder or a 0.5mm longer cylinder to pull back the compression ratio.

Cheers

 

Jack

One of the reasons for the longer Barrell in they suposedly got sick of machining the stock .040 over size commodore pistons down by .05mm.

I learnt this when I had to replace one piston earlier this year....

 

If you compare an unmachined piston, I had both in hand. We wondered why there was visible difference. As far as I know compression difference, is achieved by different "indent" in the top of the piston.

 

It makes replacement Barrells and pistons a bit tricky..

 

wg

 

 

[Guest 4aplat]

My two bob's worth: I have a hydraulic 2.2 in my little Jodel D9.

Hi

 

Is there a lot of "jojo" in australia ?

 

MicheL

 

What is the serial of your hydraulic jab ?

 

 

[Guest Maj Millard]

This problem with machine cut threads Vs rolled threads on Chromelmoly engine throughstuds, has been mentioned before several times on this forum, and in other places.

 

Anyone with any engineering nouce at all will be aware of the significent differences strength wise.

 

One of the main tasks that the through-bolts perform, other than keeping the case together is to maintain the critical clearance on the main crankshaft bearings.

 

Perhaps this is why jab engines also suffer from flutuating oil pressures and temps.

 

Anyone who has delt with Jab on an engineering level for any length of time, will know that they are reluctant to take any constructive critisim on their engines' problems.

 

Reducing the engine compression-ratio will reduce the strain on the thru-bolts, but will also reduce engine power output. If they upgrade the through-bolts to what they should be, then they can have any compression ratio they like without worry.

 

The fact that they are not aware of the reporting in CASAs' safety magazine on their engine failures, and the fact that they are just not up to speed on the through-bolt problems, comes as no surprise to me.

 

They are asleep at the wheel in Bundy, and they need to wake up and make their engines as safe as they need to be, as expected by the customer, and the customers' innocent passengers. To simply throw a "new upgraded engine" at a customer after yet another failure is just not good enough. That has been their supposed solution for years now, but still the "new upgraded engines' fail. We don't want mass produced cookies, we want reliable and safe aero engines..............................................Maj...

 

 

[RKW]

I have to agree with you, Major. Cut threads leave a stress point where the thread ends. A rolled thread will always be stronger. Maybe I am oversimplifying a more complex problem, however, I believe a high tensile rolled thread stud of similar design, would solve the problem. Irrespective of what ever else is causing the problem, the catastophic failure occurs when the studs ends let go. I have expressed these comments to Jabiru now on two occassions.

 

I note that the new engine has spacers at the base of the cylinders. I presume these are the .5mm ones designed to reduce the compression ratio. It runs well now but how will it be around the 300 hour mark??

 

Jabiru have ironed out a lot of other problems with their motors, but appear reluctant to tackle this one.....Best Regards, Bob

 

 

[Guest Maj Millard]

Thanks RKW, It's good to hear that they take care of some problems. The solution to this one is simple really...spend the money and upgrade the through-studs to rolled thread high-tensile, or whatever it takes. This item is of major important in any engine case, and certainly in one with an aluminum case.

 

I feel the customer has a part to play here also, in not accepting any more rubbish out of the factory. Make your failures (minor or major) known to the factory, then they have no chance to say "oh were wern't aware of that ".......................Maj...

 

 

[Old Koreelah]

Hello 4aplat, there are a few Jodels in Oz (see the yahoo Jodel forum). My D9 is powered by Jab 22A3178.

 

 

[Guest 4aplat]

Jojo are very good planes

 

and your jab's serial says that you won't encounter pbs with it

 

a friend of mine has a jojo with a jab abd was very happy with it

 

MicheL

 

 

[RKW]

I have it on good authority that Jabiru have a new thru-bolt in the pipeline. I believe it is made of the same material but has a larger diameter. Whilst not ideal, it may yet solve the problem. How the new bolts will retrofit is another matter. Anyway, it is pleasing that Jabiru are finally addressing the problem.

 

 

[Dieselten]

Another failed set of through-bolts to report....

 

On 23rd December 2010 Jabiru engine 2200B no 102 had two through-bolts shear whilst on descent at 2800RPM, carb-heat on and fuel-boost on (detonation? I don't think so!...carby-heat makes the mixture richer, remember). This engine had 675.8 hours at time of failure, the heads were overhauled at 500 hours. Very disappointed. This mill has been maintained by-the-book (or better) by a Level 2/LAME.

 

Managed to reduce power to 1800 RPM and nursed the dying engine back to the runway from 4 miles out, landed, taxied off, shut the mill down and found top and bottom through-bolts on the two rearmost cylinders both failed, a straight shear with a martensitic appearance across the bolt at the thread and the last piece appeared to be more of a plastic failure. Negligable signs of fretting of crankcase, but it's probably in need of line-boring. Engine rotates freely by hand and still has good compression, but it's probably in need of a bulk-strip and zero-timing. Basically, the engine is probably toast. Now it's a case of how much to zero-time and upgrade this unit versus how much for a zero-time upgraded engine from stock.

 

Incident report sent to RA-Aus, engine going back to Jabiru as a running-core at time of shutdown.

 

Come on guys, my Rotax 582 lasted longer! It did 762 hours and was still running perfectly when it had a rebuild due to a failing alternator.

 

Now, are we going to get a service bulletin requiring us to replace all the trhough-bolts and studs at 500 hours (the traditional line-of-least-resistance), or will the manufacturer finally come up with a through-bolt with either a round or square thread, rolled into the bolt instead of cut, and a bolt of sufficient diameter to last at least 1000 hours?

 

Alternatively, re-manufacture the crankcases with a web for bolts to hold the crankcase halves together and fit separate studs to hold the cylinders. Hey, it works for Lycoming and Continental! The Jabiru 2200 engine in its present configuration is just about at its working-limit. Time to bite the bullet and start making it like a proper aero-engine.

 

 

[Thirsty]

You'd think Jabiru would want to get this right?? Being fairly new to RA I'd be very reticent to buy a jab engine. This annecdotal evidence is very bad publicity. I heard an old saying once - "perception is reality". It doesn't matter if user abuse makes these engines fail (though I really doubt that's the case) - the perception seems to be that Jab engines don't last to their TBO (or even a decent percentage of it) so the reality is just that. It may be harsh and maybe if I have a jab engine and look after it by the boo kit'll last to 2000hours.

 

It's a pity 'cause I really like supporting oz companies. I really don't understand why jab dn't just make a thru bolt with a rolled thread and have done with it.

 

 

[Guest Maj Millard]

Nor I. And it won't just be Jabiru in the dock, our RA-Aus would be in there with them.Saddest of all, it seems an adverse finding by a Coroner is what it will take to have something done.

In the States they would call that a "tombstone mentality"...

 

If the RAAus came out and said Jab engines are shxx, it would upset and alienate a lot of the members, even if it was the truth.

 

RAAus is thinking with it's wallet, unfortunatly...........Maj...

[Vev]

Hi Dieselten,

 

Glad no one was hurt.

 

The engine hardly sounds like it was under any stress when it failed ... as you suggest, not a time you would expect to see detonation.

 

Couple of questions on the failure if you don't mind?

 

Were the barrels every off this engine or the studs removed? Was the torque ever checked on the through bolts and was there any movement? What was wrong with the heads when they were reco'd? Does this engine have a EGT, if so, does it ever run >1250 deg F?

 

Cheers

 

Vev

 

 

[fly_tornado]

I remember reading somewhere that if the bolts where torqued up with oil on them that could cause them to fail due to overtorquing. The idea being a dry bolt is harder to rotate to the correct torque. I was told by an old mechanic to always oil the bolts to make it easier for the next guy. Maybe because Jabirus aren't built with cast blocks has some contribution to this sort of failure.