Jabiru engine overhaul

[Keith W]

A mate of mine has 40 hours to fly on his 3300 till a top end overhaul, can anybody recommend where to get it done, before all the bullshit comments start the engine hasn’t missed a beat  in 960 hours and is running great now, he is based in Echuca.

[440032]

There's a place called Jabiru. That's the only place I would send my own engine to. I would not trust some plonk who thinks they know what they are doing.

I've even first hand seen one LAME do some really dumb schidt to a jabiru engine.

[Keith W]

Jabiru are only doing gen 4 engines atm that’s why I’m asking

[facthunter]

I can understand that. It's not Rocket science. People who do good work on Porsches (air cooled) would be where I'd go. They use cryogenic for fits. (Inserts and guides). The inserts might just dress up with a seat recut but they should be checked for tightness and recessing. Replace valves and guides and check springs and rocker geometry. You will be looking at the pistons too so I'd see if Jabiru will give you some advice there.. Presume the engine will be left in the plane.... Nev

[RFguy]

Keith, just a comment clarification -  did you say Jabiru are not overhauling  < Gen4 ? (IE 1,2 or 3) ?

 

[Keith W]

From what I understand could be wrong, my mate is more looking for somewhere he can take the plane get the engine done and pick it up when it’s finished 

[kgwilson]

If you can source a Lame with a good reputation and has done some before & is happy to provide names /phone numbers of those he's done the work for you should be OK. It is only a top end after all. Good to see it going well at 960 hours. I've got a way to go with my gen 3 at 400 hours with just oil filters & plugs replaced to date. Run on Mogas since new.

[jackc]

Is there such a thing as a factory repair manual?  What do LAMEs use for reference material in their maintenance procedures?

[facthunter]

The official Makers manual It has all the clearances , wear limits and tolerances as well as instructions on procedures.order of  assembly etc.  One of the hardest things to get right is main bearing "crush" (Interference fit). In a lot ways general principles are much the same for all motors . but some are more critical than others. where materials are concerned. ie the valve material should be compatible with the valve guide material. or it will"Gall".  Nev

[kgwilson]

5 hours ago, jackc said:

Is there such a thing as a factory repair manual?  What do LAMEs use for reference material in their maintenance procedures?

There are overhaul manuals for all engine versions that can be downloaded from the Jabiru website. The latest revision for Gen 4 engines (revision 11) has just been released on 23/1/23. The latest release for the earlier engines was released on 23/11/21 and is revision No 23.

 

Anyone with the appropriate skills and equipment could overhaul a Jabiru engine so long as they follow the process and procedures as per the manual and don't cut corners or decide to make modifications. Only appropriately qualified people are able to overhaul factory built aircraft (24 reg) Jabiru engines.

[RFguy]

I would add my 2c in that the 1000 hour is a crankcase split  is alot more involved that just pulling the heads off and cleaning up heads, guides, pistons which 'any mug can do '.

IMO the level of experience and competence is an order of magnitude for a full overhaul compared to the top end overhaul or refresh. 

Saying all that, people dont seem to report too much difficulty with reassembling the crankcase and not having a crankshaft and camshaft (which runs in the aluminium casing )  bind. 

 

Jabiru's price for doing a overhaul I think is reasonable.  Parts are not priced like Rotax- Rotax wants you to buy a new engine and that's why a ring set is $270 for a single piston for a rotax and $35 for a jabiru. Although rotax will go reliably 2000 hours without blinking ..but then u have to chuck it out. 

So- you might consider taking it to your favourite mechanic, removing the engine and sending to Jabiru.  Or flying it to Bundaberg is I think much easier unless you are in WA....

-glen

 

Edited February 1, 2023 by RFguy

[Thruster88]

You could say jabiru want people to buy a new gen4 if they are no longer offering rebuild on the older engines. 

 

Keith W's friend  would need to check price and availability on the long list of mandatory replacement items for the "top" overhaul plus the labour to dismantle, check and reassemble the engine. Add the small value of the old engine and compare the total with a new gen4. Cheapest is not always best in the long run.

[facthunter]

I wouldn't say "any mug can do" the top end. . On many engines a top end is all that is required at those hours.  Does everyone as a matter of course check the rocker geometry and the oil removed hydraulic lifter clearance.? Those things are critical as well as the valve seating .   Nev

[RFguy]

Thruster is right about the mandatory updates applied when Jabiru do an overhaul. (which is good) -  In this Gen3 engine I recently bought, it  was overhauled in 2015 by Jabiru and they upgraded the engine to the very latest feature and SB spec.  - solid lifters to Hydraulic rollers, new camshaft, new pushrod manifolds,  internal pushrod oiling, full flywheel attachment kit, dowels in the crankcase >>  prop flange  interface... new oil pump rotor, double valve springs, etc etc 
All that would have been in the end , quite a bit of coin --- IE the basic overhaul  of pistons, valves,  gaskets, rings, rockerbushes would have been peanuts. ....
Hence maybe wait until a Gen4 engine is available (get in the queue) and run 'on condition' (which you are not permitted to do )  if leakdowns are good (>65 to 70) . I would think at 960 hours it would be tired.  But the bottom end as nev says is likely fine. they rarely (I dont know of any) that give problems ever. 

Edited February 1, 2023 by RFguy

[BrendAn]

On 31/01/2023 at 4:18 PM, Keith W said:

A mate of mine has 40 hours to fly on his 3300 till a top end overhaul, can anybody recommend where to get it done, before all the bullshit comments start the engine hasn’t missed a beat  in 960 hours and is running great now, he is based in Echuca.

if you want the best ,take it to wayne johns . even jabiru engineers recommend him.

Edited February 1, 2023 by BrendAn

[spenaroo]

16 hours ago, RFguy said:

I would add my 2c in that the 1000 hour is a crankcase split  is alot more involved that just pulling the heads off and cleaning up heads, guides, pistons which 'any mug can do '.

IMO the level of experience and competence is an order of magnitude for a full overhaul compared to the top end overhaul or refresh. 

Saying all that, people dont seem to report too much difficulty with reassembling the crankcase and not having a crankshaft and camshaft (which runs in the aluminium casing )  bind. 

 

Jabiru's price for doing a overhaul I think is reasonable.  Parts are not priced like Rotax- Rotax wants you to buy a new engine and that's why a ring set is $270 for a single piston for a rotax and $35 for a jabiru. Although rotax will go reliably 2000 hours without blinking ..but then u have to chuck it out. 

So- you might consider taking it to your favourite mechanic, removing the engine and sending to Jabiru.  Or flying it to Bundaberg is I think much easier unless you are in WA....

-glen

 

...... Have you bought parts to rebuild a car or motorcycle recently?
that's a pretty reasonable cost for OEM piston rings.

[jetboy]

firstly, last time I read the mtce manuals the "top" is not required at exactly 1000 hrs, It is a guideline and they expect the top to have been done once before the 2000 hr mandatory overhaul interval.

 

So if all is well you should be able to run a couple of hundred hours further, particularly if any valves or rings work has already been done.

 

Secondly, I dont recall any of the "top" items requiring splitting the cases, I assumed you can change the conrod bearings etc without doing total overhaul - check the manuals though as I dont need to look at this myself for another 600 hrs

[facthunter]

Why would the bearings require anything at those hours?  You have an in line filter and changing the oil at 50 hours is common.  I doubt a Jab top end will go 1,000 hours but if everythings ok leave it till it's not, but IS it? Valve guide wear is not easy to check unless you know what you're doing and if there's any stem stretch change the exhaust valves early. They aren't expensive.  Nev

[RFguy]

Jabiru  are not upgrading/refurbing Gen1 engines-  they are doing Gen2, Gen3 ( A Gen2 is not a long way from the Gen 3).  (when I asked 3 months ago) .

Gen4 production rate should be improved by mid year. 
 

Jabiru top end should go 1000 hours IMO on ULP fuel  only, if head recession doesnt get you causing valves to not fully close. 

Nev you are right-  case split is NOT mandated, but parts like  replacement like valves at 1k hours must

Jetboy. true.  bit of interpretation of the manuals. Jabiru talk of engine cycles- 1000hours each cycle, max of two cycles if it is a 24-

 

HAVING SAID ALL THAT- with pistons off and crank and cam feeling good  and  no unexpected metal in the filter -  In My opinion,. it is likely unnecessary to split the case from my POV and the way I interpret the manual. ----- Engines sent to Jabiru - Jabiru though would likely split the case at 1k hours.

 

Section 2.7, 2.8

particularly : "The intention is that an engine will initially be stripped and the mandatory replacement parts will be discarded"

Interpret this how you will...

 

 

 

 

 

 

 

[RFguy]

Section 2.7, 2.8 and  2.9 and Section 3.3 IMPLY that the engine whatever the situation, will be stripped down and clearances and tolerances measured.

That's what Jabiru do if you send it to them . They will split the case and measure everything. 

Now, if the pistons etc are off, and it is found that there is no undue play, friction etc and no serious metal in the filter, then it's likely to be not required to split the case- but Jabiru would. 

 

 

[jackc]

My opinion only, IF barrels and heads come off for a reason, then I would also split cases and measure everything and replace everything that is not to spec. Crank measures up passes crack testing,  replace all bearings, seals.

Its my policy for car, motorcycle engines.  I hate pulling things apart for a second time because  I short cut somewhere.

[facthunter]

Why do other than what the manufacturer recommends as normal? It's pretty much always the case that the heads require work before the rest does.. By all means do it if there's some indication of an issue Like low idle oil Pressure, metal in the filter or a vibration/noise that's unusual or the motor has been overspeeded..  What you do work on, don't skip the quality of.  Nev

[RFguy]

Jack, I disgree. IMO Jabiru bottom ends 'never' (IE rarely) need work- only for prop strike ..... 

Barrels and heads always come off....with ring replacement pretty much mandatory (IE it will need to be done) . heads needs to be cleaned up, guides  and valves inspected and cleaned, recession assessed, hone and back on they go.  

 

[jackc]

My personal reasoning is, IF you dont own the engine from new, its past history may be against it despite the fact that factory would see no requirement in general, to strip bottom end.  Its more a personal thing for me. 

[facthunter]

I would most likely do the same myself but it's not justified cost wise in normal circumstances for the average person. PROVIDED  all indications are good. it's the same for any motor anytime If it rough or shaking it won't come good by itself, reliably and something would have caused it. When props were hand swung you "felt" how good the compressions were when you were priming the engine Even a relatively new engine can have issues. I personally don't like Hydraulic lifters in an aircraft engine and never will. Checking those tappetts will tell you if something's not right.BEFORE it lets you down. Usually.  Nev