Rolled Thread Engine Through Bolts Available as alternative

[jetboy]

They already make certified and non-certified engines. you just pay more for the cert. one.

 

The difference between a certified engine is that one of them has managed a 50 hr endurance test.

 

The spec is JAR 22-H (EASA CS-22) and also ASTM F2339-04 for some engines

 

This is also the spec for the Rotax 912A

 

The 912S and -F comply with the real aircraft certification FAR-33

 

This requires an engine to go a whopping 150 hours without failure, if that makes you feel better.

 

The way Jabiru continually fettle their production engines whilst claiming they are still certified is beyond belief.

 

But given the standards met, it doesnt really matter.

 

Ralph

 

 

[Guernsey]

Thanks Ralph much appreciated.

 

It does make you wonder then why they don't make the various improvements on the non certified engines.

 

Alan.

 

 

[Guest Maj Millard]

Excuse me if I'm out of line here, ( I often am when it comes to Jabs it seems !)......However if these so caller Jab certified engines are still experiencing unplanned failures, as we all know they are, then who the hell certified them ?...and under what testing programme ?....

 

Seems to me somebody has dropped the ball badly here, be it either jab for pulling the wool over CASAs eyes, Casa for not checking the testing program for the engine, or CASA for not having a full and adequet testing programme requirement in the first place. Could well be a CASA Licensed CAR 35 engineer not doing his bit in there somewhere also..Somewhere, somebody hasn't done the job completely IMOP.......................................................Maj...

 

 

[brilin_air]

And we all know that only Jabiru engines fail, and no other aircraft engine has ever had a failure of any sort

 

 

[Guest Maj Millard]

Hi there Brian and Linda, Of course you are correct in saying that any engine can fail...and they do. However by way of this forum, and (often spirited ) discussion, we are highlighting an engine that has been produced and sold with now well demonstrated shortfalls. Why do we have to highlight these shortfalls at all ?.......because the factory wasn't,.... or even acknowledged that there was any problem, a couple of years ago.

 

Hopefully our forum discussions will lead to safer engine operations in the future. The factory is now participating in a through-stud replacement program, which would not have happened without us making a noise on this forum........................................................................Maj...

 

 

[brilin_air]

Jabiru engines are a great engine when they are treated right, the faults that are happening are reasonably easy to fix, the problem is the certification system that is in place which prevents people from straying to far from the standard engine design, even when a better way is found to improve the overall design. These engines can acheive very good temps at cruise, EGT's that are within 20 deg C over all cylinders and CHT's that are about the same with a few tweeks, all without liquid cooled heads and fuel injection. You don't need to over complicate things by adding so called fixes when you can build the engine to achieve the desired results. The best thing about a Jabiru engine is the simplicity in the design and the cost of parts. Which is something that if it did not exist would prevent a lot of people from flying.

 

Brian

 

 

[dazza 38]

So does that mean that the bloke with the brand new 2200 donk that had a engine failure at 8 Hours TT since NEW ( suspected to be a Valve spring) .Didnt treat his engine right ?.

 

Or the bloke with the 3300 that had Qty 2 through bolts fail a a Massive Total Time of 21 hours since NEW.

 

Or the bloke who had his 3300 engine failed at a TT of 60 hours Since New. Fault found , not known when printed.

 

Or the bloke whos 3300 Rocker bushes deteriorated in his engine with a TT of 25 hours since NEW.

 

Or the bloke whos rocker bushings (2 off 12) failed within 2 hours of fitment.

 

Come on, its stretching the truth a bit to say that jabiru engine fail because they are not treated right.

 

By the way-The above defects are one that have reported over last two months.I would hate to think how many there have been since 1995.

 

 

[brilin_air]

Ok so you can quote 5 engines all with different faults, big deal.

 

Check out the latest Flight safety magazine and see how many continental and other engines that have failed, some are low hour engines and some have lots of hours on them, and they would have recources that would be second to none. We are talking about a mechanical piece of machinery that does and will have failures, doesn't matter who makes it.

 

If someone thinks they can make a better product than Jabiru then they should go ahead and do it, but don't go bitching about a product that has some failures unless you can come up with the answer to fixing them.

 

If you don't like the product no one is forcing you to purchase it.

 

Brian

 

 

[bushpilot]

I'm with the Dunkleys here> Go look at the Rotax forums and see the failures that they report.. Same with Lycs. and Contis.

 

We have 2 3300 motors and 2 2200s. They have done around 1170, 780, 690 and 340 hours - and have never had more than the required maintenance done on them. We did have a crankshaft gear failure on one 3300, but this was a very rare component failure. But, as others have said, they must be serviced / maintained in accordance with Jabiru manuals..

 

 

[fly_tornado]

Flying schools do lots of circuits though, most private Jabs wouldn't.

 

 

[dazza 38]

Sure they must be serviced, a bit hard to service a engine that fails before it gets to the first service though.

 

 

[JabSP6]

Thanks for all the input on this thread guys but it is getting off track now so i ask the Moderator to close this thread and you start up another about Rotax V's Jabiru or one about Certified V's Non Certified engines

 

Cheers

 

JabSP6

 

 

[Guernsey]

Sure they must be serviced, a bit hard to service a engine that fails before it gets to the first service though.

I agree and what if those failures caused a loss of life.

 

Alan.

 

 

[Tomo]

C'mon guys, be nice, Jabsp6 has asked for it to stop, so lets do so eh?

 

 

[turboplanner]

Thanks for all the input on this thread guys but it is getting off track now so i ask the Moderator to close this thread and you start up another about Rotax V's Jabiru or one about Certified V's Non Certified enginesCheers

JabSP6

(line has been moderated - attacking fellow site user - Admin)

 

The cold hard fact is that we read frequently in the RAA magazine about the failure of these bolts.

 

In many cases, MANY cases the failure is accompanied by a forced landing.

 

That so far all of these landings have been made without injury is a credit to the Pilots and the RAA system which trained them.

 

HOWEVER, this is a game of Russian Roulette. With so many aircraft going down, inevitably someone is going to mess up the forced landing, or find themselves over forest etc and there's going to be a fatality.

 

The Manufacturer needs to exercise some responsibility and solve this issue sooner rather than later.

 

It wouldn't be the first time that people who've boasted how good their aircraft was have been its victim.

 

 

[JabSP6]

Turbo

 

I could not agree more with what you have said.

 

From Jabiru's point of view they have solved this issue by upgrading all of the motors leaving the factory with the larger 7/16" through bolts.

 

The problem is that for all of us that still run the 3/8" through bolts it is a major job to convert to these bigger bolts.

 

The motor has to be completely stripped and bigger engine case locating dowels fitted and barrel mounting holes drilled out before reassembling again.

 

I simply looked for another alternative to doing this as i felt it was a lot of work when there might have been an easier way.

 

Changing from a Machined Thread Bolt to a Rolled Thread Bolt of the same size was a much more practical solution and far more cost effective one for me.

 

The problem i have found with this is it is not a solution for everyone especially those with factory built planes even though the bolts are manufactured by a reputable Bolt Manufacturer be that ARP or Alliance Fasteners.

 

I would suggest for all those out there that have any concerns at all about this idea to do what the factory recomends and pay the extra money and convert to the 7/16" bolts.

 

As i have always said i am looking for ways to make this great motor more reliable but would never compromise its safety.

 

Safe flying

 

JabSP6

 

 

[Dieselten]

Gentlemen, check your through-bolt nuts and the "Torque-Seal" lacquer (on factory-built or re-built engines) carefully!

 

At 818 hrs TTIS (with a full factory rebuild at 675 hrs) my 220 engine showed signs of black oil emerging at the upper base area of no. 4 cylinder. The "Torque-Seal" lacquer had vanished from the rear upper through-bolt nut on the same cylinder.

 

Being of a suspicious nature, I took this to indicate the nut was loosening on the through-bolt, in spite of being "securely" glued in place with Loctite 620.

 

So, taking my two "Snap-On" 12-point adapters (as recommended in the Jabiru engine overhaul manual) and my trusty torque-wrench, and calculating the reduction in torque required for the added length due to the adapter, I had the offending nut torque-checked...and it moved about 15-degrees of angular movement before the torque-wrench clicked off. That nut was working loose!

 

Conclusions:

 

i) any sign of black oil at the base of any 220 Jab engine should be taken as indicating a developing through-bolt tension issue which needs URGENT attention,

 

ii) the Loctite 620 recommended by Jabiru is not going to hold the nuts on the bolts, and

 

iii) the use of "Torque-Seal" as a first-line-of-defence indicator of a developing tension issue has merit.

 

At the next 100-hourly I'll get the L2 or LAME to torque-check all the through-bolt nuts...and if we see any sign of black oil seeping from a cylinder base in the interim then we'll whip all the heads off and do the whole lot right there and then.

 

You are forever putting the spanners to the 2200 Jab engine. I just hope I have nipped another engine-failure in the bud.

 

 

[JabSP6]

Diesleten

 

Sorry to hear you are still having issues with your motor. Great work spotting this one early. Only 140 odd hours on it this time. Thanks for sharing your experience with us here. This is exactly why i joined this forum in the first place. I am just curious if this motor came back from Jabiru with the Bigger 7/16" throughbolts or just had the longer 3/8" throughbolts fitted and the ARP nuts glued on with Loctite 620?

 

As i said befor thanks for the heads up on this situation.

 

Safe Flying

 

Andrew

 

 

[rogerpl88]

Gentlemen, check your through-bolt nuts and the "Torque-Seal" lacquer (on factory-built or re-built engines) carefully!At 818 hrs TTIS (with a full factory rebuild at 675 hrs) my 220 engine showed signs of black oil emerging at the upper base area of no. 4 cylinder. The "Torque-Seal" lacquer had vanished from the rear upper through-bolt nut on the same cylinder.

 

Being of a suspicious nature, I took this to indicate the nut was loosening on the through-bolt, in spite of being "securely" glued in place with Loctite 620.

 

So, taking my two "Snap-On" 12-point adapters (as recommended in the Jabiru engine overhaul manual) and my trusty torque-wrench, and calculating the reduction in torque required for the added length due to the adapter, I had the offending nut torque-checked...and it moved about 15-degrees of angular movement before the torque-wrench clicked off. That nut was working loose!

 

Conclusions:

 

i) any sign of black oil at the base of any 220 Jab engine should be taken as indicating a developing through-bolt tension issue which needs URGENT attention,

 

ii) the Loctite 620 recommended by Jabiru is not going to hold the nuts on the bolts, and

 

iii) the use of "Torque-Seal" as a first-line-of-defence indicator of a developing tension issue has merit.

 

At the next 100-hourly I'll get the L2 or LAME to torque-check all the through-bolt nuts...and if we see any sign of black oil seeping from a cylinder base in the interim then we'll whip all the heads off and do the whole lot right there and then.

 

You are forever putting the spanners to the 2200 Jab engine. I just hope I have nipped another engine-failure in the bud.

Dieselten,

 

Sorry to hear of your problem. A couple of observations.

 

1. Oil leaking from the base of the barrels does not necessarily mean that the nuts are getting loose. It could be worse. It could mean a failure(s) of the bush o ring seals which the through bolts go through. Since it is a through bolt, check the other side of the engine and if there are signs of oil seeping near the corresponding through bolt then use must be suspicious of these seals.

 

2. If the through bolts are failing because the threads are undersized then increasing the bolt diameters are not going to improve matters. Using locktite to make good is not good engineering practice - especially as the locktite can soften when heated.

 

I cannot understand why owners are prepared to use through bolts with poor quality threads

 

Roger