Jabiru Gen 4

[Bruce Tuncks]

We had the very first gen 4 engine here at Gawler. We got it partly for a beta test and we were happy with this. It was showing no problems at 500 hours when we were told that the factory had identified a weak spot in the cylinders and soon after, the engine started running rough. The cylinders were replaced by the factory. There have not been problems with later gen 4 engines around here to my knowledge.

Personally, I have had no problems ( except a self-inflicted one from high-power ground running ) with my 1998 engine and it now has 700 hours. I am planning to replace it with a gen 4 engine one day, so I am very interested in how they are going reliability-wise.

I really like the way the gen 4 engine remains bouncy when you turn it over when hot. My steel cylinders with aluminium pistons go so tight it feels like they would generate too much friction to run. Since it runs fine when hot, I really can't explain this.

[Corky]

Why even engage with him, unless he has changed engines he doesn’t have a Gen 4

Turbo,

Don’t talk rubbish l have own 4 jabs one 4 cylinder never missed a beat and 3 6 cylinders 2 modified by Micheal Sharples and didn’t miss a beat and one certified built by Jabiru. I have done 1500 hrs behind These engines, l have had some great ones and a couple shit ones. My plane have always been serviced at 25 hr intervals and all the problems l have had over the years have been caused by jab covering their arse.

[Corky]

Here we go again. Putting a cork in it would seem quite apt.

Here we go again. Putting a cork in it would seem quite apt.

Wilson,

The reason I don’t go on this site any longer is because of guys like you who talk rubbish haven’t done the hours behind these motors and who havent experienced the problems and issues with these motors or the company. Why should you have to go and buy Jen 4 which l would like to say isn’t proven yet when l have got an existing six cylinder that should do the job which l paid for.

[Bruce Tuncks]

Let's all be more polite huh guys. And corky, I know jab 7252's engine quite well and not only has it never had a problem, it has near-perfect leakdown figures. It gets an oil change every 12.5 hours, which may explain the leakdown results.

From the adjacent hangar, there is a Camit engine that flew to William creek twice in 2 days to rescue a rotax-engined plane. Not that there was too much wrong with the rotax engine, but it did have a serious coolant leak.This could have been very expensive but the club had resources to handle it, like the generous member with the Camit Jab.

 

I have to agree that Jabiru engines need careful operating and maintenance. Nearly all the problems we had with an early club-operated plane were due to not knowing enough about how to look after them. For example, we operated with a loose propeller for months, until the wooden prop cracked near the hub. It wasn't as if the prop felt at all loose on turnover, but it clearly was hammering during running.

We could easily have had broken flywheel bolts.

It wasn't only us that had a lot to learn, Rod Stiff and the factory did too. Look at the iterations of increasing cooling fin area over the years, as well as the improving instrumentation.

Personally, I am happy to be a small part of this Australian engine development. I would never have afforded a new plane without them.

[facthunter]

There have been specific issues with some Jab motors over the years. I don't claim to know the lot but people just saying they are $#1T (in so many words) miss the point that many get a good run IF they do the right thing by the engine. No aero engine is "fit and forget" but the 80 HP 912 was close in the early days but it had starter drive issues and even crankshaft failures and red. drive issues. Liquid cooling makes it less touchy with temps but not everyone wants the complexity and weight of liquid cooling.

TBO is not a guarantee with any engine. A maker can pretty much claim whatever they wish. (these days) Engines with TBO's like say a P&W R-2000 had tbo's of over 2,000 hours but they would require a bit of work now and again on cylinders but the basic engine did generally do the 2300 hours depending on their age and what environment they were working in. I've been involved with some quite spectacular instances where they didn't make TBO at a far worse rate than Jabiru are accused of achieving. The Merlin never had a TBO over 650. and it's an expensive well built engine. Plenty of engines need a top at around 400 hours. Leaving the engine sit for weeks doesn't help. Aero engines, like many others run best when used a lot. IF they sit the should be properly inhibited. I could assert that it's never done properly in the U/L area and even rarely in GA..

Every owner should expect honest updating of the engines issues. That's the expected connection between supplier, authority and user in the aviation game. At one time the GE CF6 was having the hot end turbine inspected EVERY turnaround in this country. I know that because I was involved with it. and carried the details of the required inspection on my person here from France. (around 1981). Aviation is where we all work together to improve the outcome.

Any piston engine that has unusual friction, stiffness etc is not safe. The engine should bounce off compression as it does when new. Radials don't as they have so many overlapping cylinders it's not so obvious. A high rate of breathing (blowby) should ground a four stroke aero motor whereas and old clunker car can keep going around town for years in a poor state. One stuck valve even for a short period can severely damage a motor. Jabiru valve failure is usually from excess heat and it stretches and cracks the stem. On the earlier motors, that showed up straight away in the valve clearance changing. The hydraulic lifters mask that and can themselves fail (even in a Rotax). I've had one nearly kill me in a Continental O-300.. I would rather have manual adjustment, personally. Nev

[Yenn]

The TBO of a Merlin does not bear comparison with the other engines we talk about. It was designed for massive power and a short like, originally as a racer, then as a military engine,

[dlegg]

When people ask specific questions on subjects there tends to be a drift away from the subject by well meaning and experienced members who are very knowledgeable but who do not have actually experience in the question asked, and then it turns into a them and us discussion (in this case Rotax v Jabiru) . I would respectfully suggest that when asked a question on ANY forum subject that if you have first hand experience please give us the advantage of that experience, if not don’t enter the discussion

You are so right there Paul. Lots of posts now into this thread but I'm still no closer to getting any answer to my questions. I would really like to know if the Gen 4 is a direct swap for my Gen 2, will my cowling fit over the cooling ducts as fitted to the Gen 4?

[Guest Machtuk]

I operated for a while perhaps one if the best air cooled engines made in modern time, the Lycoming 0235 with a TBO of 2400 hrs, you simply couldn't kill that engine! Clean oil change every 30 hrs I did and manual tapper adjustments. So far my 2200A Jab motor with solid lifters seems to be pleasing me the same as the Lyc. I am a huge believer of clean oil always have been, change my Ford oil every 10000k's, (close to half mill k's) oil is cheap especually for a Jab donk!

[facthunter]

The Merlin comparison is VALID as it was in a civilian context that they achieved the 650 hours. Most engines had a military version which ran harder and had a shorter life.. Merlins also had inherent design reliability issues . One was the non roller camshaft followers and another the shared magneto skew gear drive that failed and dropped both mags out at the same time. . Nev

[Paul davenport]

Please with all due respect to every one, Merlin, P&W , Rotax and any other engine EXCEPT Jabiru have no valid issue here. The original question was ONLY about Gen 4 Jabiru engines, I say again if you have knowledge about the original question please let us have the advantage of your experience, all other conversation is simply not relevant and Only those who have done the installation have the experience to reply The question has nothing to do with how good or bad any other make of engine is

[turboplanner]

The Merlin comparison is VALID as it was in a civilian context that they achieved the 650 hours. Most engines had a military version which ran harder and had a shorter life.. Merlins also had inherent design reliability issues . One was the non roller camshaft followers and another the shared magneto skew gear drive that failed and dropped both mags out at the same time. . Nev

The engine the OP is talking about is the Jabiru GEN 4, Jabiru's new engine, and he was looking for some dimensional information.

 

If he ever wants opinions on the previous model Jabiru engines there are around 54 posts repeating the hundreds of posted opinions on other threads on those previous Jabiru engines, as well your comparison with the Merlin engine, but none of them relate to the GEN 4 engine he's asking about.

 

There are some other unsubstantiated rumours, but they petered out, and still no reports by RAA, so things are looking good for this engine.

[facthunter]

ALL I'm trying to do is put Jabiru's ALLEGED BAD record in perspective, I've said all along there are PLENTY of much worse engines out there from the reliability aspect and I'm quoting the respected fully certified ones as examples. . I want to see the Jabiru be allowed to continue in this country. not be constantly bagged by those who don't have one or any personal experience with them or just read the headlines that would condemn them If you didn't get the FULL picture. I'm also trying to convey the reality that ALL engines can fail regardless of whose name is on the side of them. Nev

[Guest Machtuk]

Please with all due respect to every one, Merlin, P&W , Rotax and any other engine EXCEPT Jabiru have no valid issue here. The original question was ONLY about Gen 4 Jabiru engines, I say again if you have knowledge about the original question please let us have the advantage of your experience, all other conversation is simply not relevant and Only those who have done the installation have the experience to reply The question has nothing to do with how good or bad any other make of engine is

 

Fair enuf Paul?

[facthunter]

CASA did CHOOSE make a comparison that was based on flawed analysis and dubious figures and a lot of innocent people suffered big losses. The question of just WHAT is satisfactory must necessarily arise from that approach. I hope we don't go down that path again, as it's ill advised.., The fact the new cylinders have better compressions and less friction is a good sign. Accumulated hours will tell in the long run as they do in all such things., Runs on the board,, Nev

[turboplanner]

ALL I'm trying to do is put Jabiru's ALLEGED BAD record in perspective, I've said all along there are PLENTY of much worse engines out there from the reliability aspect and I'm quoting the respected fully certified ones as examples. . I want to see the Jabiru be allowed to continue in this country. not be constantly bagged by those who don't have one or any personal experience with them or just read the headlines that would condemn them If you didn't get the FULL picture. I'm also trying to convey the reality that ALL engines can fail regardless of whose name is on the side of them. Nev

The GEN 4 engine has no bad record which needs to be put in any perspective!

Why are you floating this nonsense?

[turboplanner]

CASA did CHOOSE make a comparison that was based on flawed analysis and dubious figures and a lot of innocent people suffered big losses.

That was not true, even though it has been repeated hundreds of times. The figures given out by Peter Gibson, the CASA public relations person, who quoted a report given to him by someone from RAA on Nov 3, 2014 and included things like flat tyres, were not needed by CASA, who had sent their own people in a couple of years before.

 

The CASA assessment was against FAA Policy PS-ANE100-1999-0006.

The records data used in the assessment was from January 2012 to July 2014, and the rate exceeded the benchmark.

I posted the details last week.

Anyone could have contacted CASA and found out for themselves.

[Jabiru7252]

What about al the other problems???

 

None, zilch, not a sausage.

[Bruce Tuncks]

There has been at least one changeover from an older engine to a gen 4 engine around here. It is quite possible, but like most things, there are a few details which take time and effort to keep right.

So it is not as easy as replacing with an identical engine, but by no means impossible.

[facthunter]

What is the benchmark Turbs?. and what do you do with the OTHER engines that fall short of it? I think you see my contribution (s) as rubbish without reading it/ them, properly. Nev

[turboplanner]

What is the benchmark Turbs?. and what do you do with the OTHER engines that fall short of it? I think you see my contribution (s) as rubbish without reading it/ them, properly. Nev

I posted the FAA policy which CASA used on the data they obtained between 2012 and 2014.

You can calculate the benchmark which triggers the action they took from that, (I didn't) the engines they assessed were five times the trigger point.

[Thruster88]

There has been at least one changeover from an older engine to a gen 4 engine around here. It is quite possible, but like most things, there are a few details which take time and effort to keep right.

So it is not as easy as replacing with an identical engine, but by no means impossible.

 

I guess that is what the OP is asking, can you buy a 15k jab and a new gen4 for $15950 and have a pretty sweet aircraft for not much money or is there a catch?

[Bruce Tuncks]

I don't think there is a catch there Thruster, as long as you do the work yourself. If you don't have the tickets, you need to find somebody who will let you do the work under supervision without charging you too much. I reckon this is a good way to go as it is sociable and you can be sure of the final quality with the extra checking.

[RFguy]

Does anyone know if the Jab Gen4 engines are also covered under CASA instrument  CASA39/19 ?

 

https://www.legislation.gov.au/Details/F2019L00926

 

(the continued restriction 2019-2022)

 

The instrument specifies : "22A3596  and above"

 

now, if Gen4s have a different prefix, then it is not going to be "and above", and it would not apply. 

 

I asked Jabiru on a couple of occassions . no reply.. BS.

 

-glen

 

[turboplanner]

28 minutes ago, RFguy said:

Does anyone know if the Jab Gen4 engines are also covered under CASA instrument  CASA39/19 ?

Gen 4 is a different engine design; same as a "break point" in automotive terms.

[kgwilson]

My engine serial no is 33A2547 & is the roller cam upgrade with 3/8 through bolts so is not included. Mine was the 5th roller cam engine off the line in 2013. The instrument states engines with 7/16 through bolts serial No 33A2540 & above. From 33A2542 they are all roller cam upgrade engines & have 3/8 through bolts with 12 point ARP nuts as far as I am aware so the instrument is only valid for 2  33A engines. Mind you the service bulletin JSB031 includes 33A engines up to S/N 33A2574 but excludes engines with the roller cam upgrade so maybe there were some later S/Ns without roller cam followers but I doubt any had 7/16 through bolts.