Jump to content

Are Jabiru engines really that bad?


MarcK

Recommended Posts

I just would not let one run to 1,000 hours without replacing the exhaust valves at least. They put up with severe conditions. The heads of them are red hot all the time.

 

Merlins used to only run 400 hours and earlier on less than that. Most of the early Gnome & Rhones ran about 4 ..Yes FOUR hours. I'm not saying we have to go back to this, but an aero engine is not just coasting along ever. It might sound like it is just purring along, but they are always at 70-80% power. Nev

 

 

Link to comment
Share on other sites

  • Replies 201
  • Created
  • Last Reply

Top Posters In This Topic

Well I know a guy who sometimes comes on the forum here. He built his own aircraft and is a full blown LAME for the airlines. fastidious builder and craftsman and dots all the eyes and crosses his Tees as you would expect. he sold his beloved aircraft with a 2200 in it and it had around 160hrs on it I think. he wanted to do the right thing so replaced the through bolts and totally checked it all over then ran the engine it ran beautifully like a clock. He then tidied up a few things put it all back together and cowls on and gave it one last run when he shut it down it made a funny noise. He then investigated and one cyclinder had dropped the exhaust valve seat out of the head and trapped the valve so it was stuffed. The upshout was no spare parts for that head so it was 4 new cyclinders and pistons etc to get it all going again I hate to think how much probably 5 grand or so....he now flys a Rotax....I asked him how the new aircraft flys and he loves it but he did say the biggest difference was that in the back of his mind he doesnt have that little devil sitting there on his shoulder saying "when is it going to stop"

 

 

  • Like 2
Link to comment
Share on other sites

That little devil should still be there. He might loaf a bit but still be there. A mate of mine sold a couple of 230's that had been on line. The purchaser of one of them flew it to New Zealand with an airline Capt accompanying him. It ran faultlessly. I wouldn't do it myself in any single engined plane. If I did, I would blueprint an 0-235 or something. but you are looking at much, much,more money. Nev

 

 

Link to comment
Share on other sites

I have always believed that pre-ignition is the root cause of most of the problems. You don't have a lot of control of fuel that is carrried in drums. I'd be trying colder plugs too.

 

Kyle an insert coming out is usually not enough interference in the fit. I reckon they should all be put in by cryogenic cooling of the insert firs tand then you don't have to fret about the fit. Nev

 

 

  • Haha 1
Link to comment
Share on other sites

Well I know a guy who sometimes comes on the forum here. He built his own aircraft and is a full blown LAME for the airlines. fastidious builder and craftsman and dots all the eyes and crosses his Tees as you would expect. he sold his beloved aircraft with a 2200 in it and it had around 160hrs on it I think. he wanted to do the right thing so replaced the through bolts and totally checked it all over then ran the engine it ran beautifully like a clock. He then tidied up a few things put it all back together and cowls on and gave it one last run when he shut it down it made a funny noise. He then investigated and one cyclinder had dropped the exhaust valve seat out of the head and trapped the valve so it was stuffed. The upshout was no spare parts for that head so it was 4 new cyclinders and pistons etc to get it all going again I hate to think how much probably 5 grand or so....he now flys a Rotax....I asked him how the new aircraft flys and he loves it but he did say the biggest difference was that in the back of his mind he doesnt have that little devil sitting there on his shoulder saying "when is it going to stop"

They are not known as the Bundaberg hand grenade for nothing.:peepwall:

 

 

  • Like 1
Link to comment
Share on other sites

Well I am told it is a reasonably common problem with them. Quite a lot of jab engines have dropped the valve seat. I always thought that the cold fitting of valve seats was the way they had to be done anyway.Its the only true way to get a proper interference fit and for them to stay there.

 

 

Link to comment
Share on other sites

They can be checked by heating the head to a pretty high temp ( In a heat treat furnace) but I don't know what the head metal is. I am led to believe it could be a higher spec. Dropping an insert especially an inlet, makes it run real crook. Nev

 

 

Link to comment
Share on other sites

So the story goes.... They did do some mods to their engines after that time. (Lower comp and retard ignition).

 

If they never saw it it would be an assumption but they might have had enough evidence to feel they could make it.

 

There's some aerodrome that they operate from in South Africa that has a fair bit of altitude. They say they haven't had any problems. Doesn't that support the detonation theory? . Nev.

 

 

  • Agree 1
Link to comment
Share on other sites

Can anyone indicate honestly, either their own, or someone they know, and can prove, that they have a 2200 engine that made 1000 hour top end without EVER having a problem, ie, never being opened up for anything more than normal scheduled maint, and ignoring minor issues. I dont want to hear that yours made it, but you replaced the heads at 220, and 600, and top ended at 800... I want to know if ANY jab 2200 engines made it all the way.

Andy,

 

What fantasy dream are you trying to live out with that question?

 

I do know a few that have made it all the way, ..................to the chain at the bottom of a boat anchor.

 

Can't help you mate on your question don't know of any in my area

 

Alf

 

 

Link to comment
Share on other sites

So the story goes.... They did do some mods to their engines after that time. (Lower comp and retard ignition).If they never saw it it would be an assumption but they might have had enough evidence to feel they could make it.

There's some aerodrome that they operate from in South Africa that has a fair bit of altitude. They say they haven't had any problems. Doesn't that support the detonation theory? . Nev.

If bad fuel is the issue, are other engine makes having the same problems too ??

 

 

Link to comment
Share on other sites

They are not aircooled. Rotax has the heads running a bit cooler than optimum. so there is no problem that way. They recommend Mogas 95 + octane on the 100 hp. If you run avgas you can have some problems with valves seating, so it's occasional use only.

 

It's no secret, fuel mixture distribution is critical. A lean mixture detonates more readily.. It's not ever recommended as a pusher, Tornado.

 

Over propping them is not recommended either. ( Like running a motorbike in too tall a gear makes them lean out.) . I reckon the bing is "just a carb" and that's all. It is used because it's cheap and you can shape the needle to make it altitude compensating ( to a point)..Nev

 

 

Link to comment
Share on other sites

They ( jabiru)are nice if you are nice?. Most reports I have heard of , they were pretty good. I don't know what is happening lately so I can't comment one way or the other. I have my views of these engines and we are better with them than without them. They are not expensive. They certainly are not perfect, but nothing is. We are going around a bit with all this. I don't think the knockers achieve much of a constructive nature. May be it makes them feel good. Someone who has not had a good run , would feel some disenchantment. The owners who are going ok and those who are not going OK would like more real information. I've seen the inside of a few, but I would like to see all the failed ones. the advantage of the non-hydraulic lifter engines is that you can monitor your valves and seats. With hydraulic lifters they "hide" a problem till it's bigger. Nev.

 

 

Link to comment
Share on other sites

With hydraulic lifters they "hide" a problem till it's bigger. Nev.

One of the easiest things to do each day before a flight is do a pull-through, it's not a 100% fool prof analysis but it's not a bad pre-flight progamme ... if there is a "soft one" stay on the ground and check out why.

 

Cheers

 

Vev

 

 

  • Like 1
  • Agree 1
Link to comment
Share on other sites

Guest SAJabiruflyer

I really don't know what all the fuss is about. All Jabiru engines, like any engine, are perfectly fine until they're not...

 

 

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×
×
  • Create New...