Pilots/LAMES comments on Jabiru J160

[Vev]

G’day Tomo,

 

 

Yes you’re correct, oil does “wear out”.

 

 

Essentially the lubricant is made up of two parts, one being the base oil and the other the additive system. The additives do a number of things to enhance the lubrication performance in terms of anti-wear, soot and viscosity control etc etc. Over time the additive system gets over loaded (soot, acid etc) and the oil itself begins to oxidise and break down .. therefore oil (lubricant) “wears out”.

 

 

However, the response posed by BlackRod in terms of lubricant dwell periods being safe at the manufactures recommendation is something I would assume to be spot on… I would expect the OEM’s recommendations would have been supported by quality data from oil and wear metal analysis over an extended period of time.

 

 

Not withstanding all of the facts produced by the OEM... I say, oil and filters are cheap and I’m a 25hr oil man.

 

 

Cheers

 

Jack

 

 

[Mick]

Also, do you see any value in engine oil changes more frequent than Jab recommend, i.e. 25 hours versus 50 hours.

I have stripped Jab engines that have had 25 hourly oil changes and ones that have had the typical 50 hour changes. 25 hour changes definitely leave a motor notably cleaner and with less wear.

 

After what I saw I wiil be changing my Rotax oil every 25 hours from now on. I don't have to leave any for the next generation as I am not having kids.

 

 

[hfrensch]

I am a firm believer in changing the oil at 25 hours and filter at 50 hours. The 2200 Jab SK (2nd jab kit produced) which I built and now owned by my brother did 1250 hours on the last engine before requiring a top end overhaul. I ran it in on aeroshell 15W/50 as I do with all my Jab engines none have oil usage problems. The 2200 has now done another 250+ hours since top end overhaul and running sweetly.

 

Cheers Helmut.

 

 

[facthunter]

Oil Change/Filter change.

 

25 hours is OK for an engine that doesn't get a lot of use. It was 6 months also as a limiting factor. IF you had a school plane and operated where there is not much atmospheric dust, and did a fair amount of hours quickly. the oil would be good for 50. If you want to change it more often then that is your choice, but some times not necessary. You do after all have an in-line filter that filters down to quite small particles. Cut it open each time and inspect for metal particles.

 

Oil gets contaminated over time. It can also use up the additives and some extended oil drain oils only do that because of the level of additives.

 

Multi grade oils that have polimers added do not last as long as "straight' oils. The oil itself could be decontaminated and reformulated and could argueably be better than the original as some of the more unstable components would have been eliminated. Nev

 

 

[Ballpoint 246niner]

:big_grin:

 

Oil does wear out actually. I might let Vev or someone else explain that to you though.

On oil wearing out let me explain the Grey- Stokes index. Basically it's an engineering index that refers to the "tearability" of the oil and it's ability to perform the 2 basic functions of lubricating and cooling. Oil breaks down- good base grade oils take a long time to break down but the " additive pack" in semi synthetics, (anti co-agulents,anti foamers, viscosity modifiers, anti corrosive polymers etc) breaks down fairly quickly. Changing oil frequently ensure that all the man made additives are new and fresh and doing the best to protect your engine. I worked for an oil company and Wynns for a while so you get to know this stuff intimately.

 

I change oil and filter every 25hrs in my jab and every 3000 in my bikes, have done for 30 years- no problems!:)

 

 

[deadstick]

Deadstick. You say pay attention to the serial number. Why? What can the serial number tell you? For example my engine is 22A378. What can you deduce from that.My advice would be to talk to people who are running that plane and that engine to see what their experience is. There are an awful lot of jab engines out there and we don't hear of many of them failing, except from a few people who seem to be professional Jab knockers.

Hey Yenn, the latest CASA flight safety mag has 6 jabiru engine failures listed for the month, page 37 interesting to see the through bolts still failing. 1 at 360 hrs and the other at 992...

 

 

[Vev]

Through bolt failures is hardly a Jabiru only problem … this was happening on aero engines before Rod Stiff ever consider building an engine and still is.

 

 

In any case, Jabiru has done quite a lot to fix these failures over the past 18 months which has reduced the incidence significantly. They have modified the engine in a number of ways to engineer out the problem and reduce the propensity of fuel detonation, which is the primary cause of through bolt failure in Jabs.

 

Take a read of the attached “Case Check” in Jabachat for some helpful hints on maintenance procedures, albeit 99% of tool boxes won’t have the tools do the 200 hr checks on the through bolts as prescribed… you will most likely need to enlist an L2 or LAME to perform the checks.

 

http://www.jabiru.net.au/Jabachat/Jaba%20Chat%20August%202010.pdf

 

Cheers

 

Jack

 

 

[deadstick]

Uploaded page

 

Had a request from a french user to upload the page so here it is.

 

 

 

[eightyknots]

The writing is...

 

...just a bit too small to read comfortably

 

 

[eightyknots]

Thanks for that tip BlackRod, it was really easy to read that way.

 

It is similarly a concern that there also six Continental engine failures in addition to the eight Jabs listed.

 

 

[dazza 38]

On my PC (HP Notebook with attached Samsung 23" screen) if you press ctrl and +, the picture gets bigger (and bigger) and if you hit Ctrl - it gets smaller. Ctrl 0 (zero) returns it to "normal" size. Hope that works for you.

Thanks for that BR.I didnt know you could do that.Works on the Dell.

 

 

[deadstick]

Another one bites the dust

 

Another local Jab 160 has shat an engine, which was a replacement for another dead engine, it had 25 hours on it and guess what? the oil in the pan looked like gold flake, full of brass with a bit of ferrous as well. Rod at Jab was informed to which the responce was it will be alright and will run fine. well the owner elected to find the cause and low and behold the hard facing was worn off the cam lobes and two had gouges in them. I am really starting to question the legitimacy of this company, I was told when my 3300 was blowing smoke from the breather that it is fine and I can fly like that till TBO (230 hrs), not sure what planet these guys are from but the strip down proved to be anything but a serviceable engine, I don't understand what is going on here as all these incidents get reported yet there seem's to be no action against them, why is this? how can the engine be certified? anyone?

 

 

[Ultralights]

it seams to me that the current spate of bad runs on Jab engines is recent, there seamed to be a few years there with little problems after the initial issues with the 2200. our schools LSA at Bankstown has run to TBO on 3 engines now, with over 6000 airframe hours. though being the primary trainer at a busy school mean that every engine has been worked hard. even orders from the CFi are to fly the Jab at Full power whenever we are flying without a student. apparently keeps the maintenance costs and issues down.

 

could most issues stem from differences in Mixtures between cylinders? hence the temperature differentials? could large temp variations cause uneven and undue stresses on internal moving components leading to early failure and excessive wear?

 

 

[Tomo]

It seems a lot of the troubles are in the Southern parts of Australia also, I wonder if it has something to do with the temperature differences?

 

 

[dazza 38]

It is generally known, to give the engine a flogging, or more to the point ,run them at High RPM.Not baby them.But that doesnt explain why some virtually brand new engines Fail.I mean 50 hours or less.Imo it must be a Quality control problem, in either the assembly of the components, or the manufacturing of the engine components.Or maybe a design problem from the Out set.It doesnt help if the Manufacturer, rebuilds new failed engines, and does not give the owner of the A/C, who has spent alot of his or hers hard earned cash, on the Aircraft, the answers to why the engine failed.

 

To be fair-alot of their engines make TBO, no problems.I just read Nevs post.Then i realized my post was very one sided.Which isnt fair.

 

 

[facthunter]

Differences.

 

I really don't know Rob, why the different outcomes. There are a lot of variables when you consider the installation possibility, but most of the engines are installed in Jabiru's own airframe. You would think that doing circuits is a lot harder on engines than doing cross-countrys. I'm a little skeptical as to whether running these things flat out is the answer. The only thing THAT is supposed to affect is bore glazing. Most engines would stick to the manufacturers recommended oils. Some suffer from rusting of the cylinders internally when left unused for a longish period and not inhibited, as any steel cylinders would, but most of the failures are not related to that.

 

I have been working on engines all my life, and years ago when this sort of thing surfaced, I thought there would be "Blueprinted" engine solution to this. I do not believe that to be the case. I have a few theories but I certainly am not going to air them on this forum. IF someone is doing a bit of work/investigation I am happy to discuss anything with them confidentially. Some engines that are serviced by people that have a fair bit of experience with them seem to run well and they don't appear to be indulging in "snake oil" type of work, or witchcraft. The servicing seminars that I have been to are OK if some are a bit uninspiring and the best emphasise attention to the head bolts (doing it properly). The Jabbachat stuff is good and to the point. From some of the questions that appear on this forum I wonder if all Jab owners refer to the data on that site, because they should. Normally to make an adverse comment about Jabiru almost brings the "wrath of God" down upon the commentator. That's loyalty I suppose. The company seem to support the product pretty well and they have little control of how it is used. I would make the comment that some of the failures of the "certified" engines ,( Like continental) are from poor servicing and old age predominantly. Nev

 

 

[Guest Baysidelad]

Hi JabiruJoe. Have you considered a J170? I was going to purchase a J160 but once I did the flight planning I realised that the endurance was not that much more (legally) than a J120/LSA due to the MTOW. With the J170 you get an extra 60KGs in MTOW which certainly makes an immense difference when carryin 2 x POB, baggage and fuel. All the Jabiru types are solid aircraft that are well worth the money that they cost, although with a Jab you will always have to spend some money to keep them maintained as they are certainly not the Rolls Royces of RAAus aviation but they do the job really well. I have flown my J170 for 100 hours now and it is performing like a dream. I have also flown the J160 and the performance in the landing configuration is markedly difference with the J170 being much better as it has the extra long wings etc. So my advice is for you to consider what you want the aircraft for and if it is for touring, then go for the J170 as this is much better for this use due to the longer endurance. greater payload and better performance in hotter conditions. As for the engine, as long as it is maintained properly, it will give you many hours of safe flying just like most other aviation engines.

 

 

[Ballpoint 246niner]

Hey Joe, my J120C( latest) is up for sale. Climbs at 1000fpm at SL, cruises at 103kts at 2850rpm and will drink between 14/15l/ph at that. As CFI says great, honest little plane and I'm 183cm and 95kg. I flew them all before I bought it new- it is the best pilot's plane in the flock! PM me if I can help you more.