Jabiru engine overhaul

[Markdun]

Splitting the case is probably 3-4 times the hours of work than a ‘top end’ overhaul. There’sa lot more measuring and you have to deal with the cam timing and distributor drives, the oil pump and flywheel. I’ve done two cases: both had fretted cases: one was removed from an aircraft because in retorquing the through bolts the crankshaft was pinched by the main bearings and seized.  The other had no external signs of crankcase fretting and was due just for a 1000hr top-end overhaul, but when I did a torque test with new through bolts (mandatory replacement at 1000hrs) the crankshaft rotational friction exceeded the specs. Splitting the cases revealed light fretting as the cause but 3/5 main bearings were showing copper colour, ie. were worn excessively.  It’s quite possible that at 1000 hours one might want to split the cases for a precautionary inspection.... but it’s a lot more work particularly if you have to machine the crankcase halves, but not that much more expensive in parts. Removing the flywheel is fraught if the cap screws are supaglued & more so if a cap screw (or dowel) is broken off before or during removal.... budget several days just for that. Dealing with fretted cases is not easy. Most engine shops can reface the halves but I couldn’t find any that could do the tunnel boring to the Jab specs. The main issue was the small size and tight tolerance of the camshaft tunnel.

 So I’m not really sure if splitting the cases at 1000hrs is worth it or not.... if you do, you will really get to know your motor.

 

Mark

[facthunter]

You shouldn't release the grip on the mainbearings either , As you remove a barrel place a spacer there and tighten it. ALL flat motors have this difficulty. including align boring. If an early motor had reached that stage I'd ditch it rather than waste money on  it.   Nev.

[Markdun]

Nev, since I’ve made a jig to do the tunnel boring it’s not that bad. I’d do that many times in lieu of having to extract broken flywheel cap screws ... you have to drill them out with progressively larger tungsten bit drills and then chisel the remainder with 2mm wide hardened chisel being careful not to damage the crankshaft.

[onetrack]

Markdun, have you tried Loctite "Freeze and Release" on those broken capscrews? I've never heard of anyone using superglue on fasteners, but high strength Loctite (bearing mount) is the worst thing to deal with, when it comes to broken studs.

[Markdun]

No I haven’t tried freeze and release. I just wrote ‘supaglue’ instead of cyanoacrylate.   It’s whatever Jabiru use and the manual says its a Loctite product but it’s still cyanoacrylate, aka superglue. I tried heat as per the O’haul manual.  BTW it was just 3 bolts and 2 dowels and all broken off before I got the engine. But even removing intact bolts it’s pretty much mandatory to use a new high quality hex driver with a long breaker bar, apply heat and ever so gradually increase the torque, and just at the point when you think the screw head will definitely shear off it moves...& then it’s easy. The dowels were relatively easy to remove as I was able to braze on a bolt to the 2-3mm extending out from the crankshaft and use that bolt to pull the dowel out.  The flywheel bolts are now locked with Nordlick washers which I should should think will be easier to remove.

[kgwilson]

Since about 2015 Jabiru have not used Loctite on the flywheel cap screws. Nordloc washers are used now and the torque is also less so they make replacement a lot less stressful. I managed to replace all of mine using sufficient heat from a heat gun after I'd completely insulated the rare earth magnets to stop the heat stuffing them up. I was sure I was going to break one but got them all out. The Loctite previously used was Loctite 620. It is a high strength high temperature retaining compound. According to the MSDS there is no cyanoacrylate in Loctite 620.

[facthunter]

Now we are in to another aspect that's a challenge. The flywheel is held by clamping force and everything must be dry and clean there. I'm sure some magic chemical is still helpful on the faces.  Pressure the oil galleries only before you run it. Same with slipper bearings No oil behind them.  Just a slight smear on the wear faces. Regarding the Copper colour the Indium coating is very thin and mainly helps the bed in period.  Nev

[Flightrite]

If it ain't broke don’t fix it! We fiddle way too much with these engines!

 

[Yenn]

The original question was about a top overhaul and who would be recommended. As far as I see a top overhaul is not hard, follow the Jab info and you can't go wrong if you are reasonably competent. I have done it twice for a Jab 2200 with no problems, so I reckon just enquire around to find a good mechanic. Possibly talk to someone from SAAA. Norm Edmunds or Myles Brietkreutz for example.

[Markdun]

KG thanks for the correction on Loctite 620.  I’d add to Yenn’s comment that a top end o’ haul is not that difficult following the Jab material. If I was going to get someone else to do it I would make sure they give you completed engine build worksheets including the measurements and tolerances in the O’haul manual.

[RFguy]

It is true, Jabiru are no longer overhauling Gen 1,2 3. and parts wil be in limited supply. You would hope they would support all parts minimum out to 2026  (10 years since last Gen3 sold) 

[facthunter]

The engine building part of Jabiru went broke..  Nev

[RFguy]

 a full overhaul is only about 9k for  a gen4  3300 plus any unusual to be replaced  parts, so overhauls are generally good value.... (1000h is book TBO ) .
for a flying school, $9/hour is pretty good, they usually run unleaded so no 300 hour top end TBO like on AVGAS

 

Edited February 21, 2023 by RFguy

[facthunter]

There must be some Parts that are not available new and more so as time passes. I doubt it would be economical to remake many of the "superseded" models major parts. You get problems when you re use high time components with anything that isn't overdesigned at the outset and weight is your problem then.   Nev

[Markdun]

On parts, there question is which parts. Lots of parts are common to both Gen3 & Gen4 but some major parts are not, like crankcase, cylinders, heads, pistons. Probably good if someone did a table, of what is, and isn’t.  The other thing is, if Jab are not going to support providing parts, particularly consumables like distributor caps, bearings etc, then Jab should provide OEM specs and part numbers to assist ppl finding alternative sources.

 

 

[Blueadventures]

37 minutes ago, Markdun said:

On parts, there question is which parts. Lots of parts are common to both Gen3 & Gen4 but some major parts are not, like crankcase, cylinders, heads, pistons. Probably good if someone did a table, of what is, and isn’t.  The other thing is, if Jab are not going to support providing parts, particularly consumables like distributor caps, bearings etc, then Jab should provide OEM specs and part numbers to assist ppl finding alternative sources.

 

 

And when Gen5 is here gen4 will be same.  Not good enough they need to offer better support.

[facthunter]

. The circumstances around the older motors are such that continued manufacture was not Possible. When you go broke you may even lose your house and certainly tooling etc would have to be sold off.. Being realistic there was no way the parts could ever be made at a price where it would survive.. It's the same with any of the older stuff and it's a miniscule market and demand you are dealing with. Probably about the hardest anyone could enter confidently..  The materials cost here is above what China can make the whole product for. Nev

[onetrack]

Most manufacturers work on 20 years as the limit to which they will supply parts for their manufactured automotive products. After 20 years, you become reliant on aftermarket suppliers to provide components - and they will only manufacture "fast-moving" parts - the ones that wear out the most.

With Japanese automotive products, the Japanese manufacturers go through the factory warehouse once a product reaches 40 years since introduction - and they grab every single new part and component off the shelves for that model, and send them to scrap - then they dispose of all the factory books, records and blueprints for that product - so effectively, there's no trace in the HQ, factory or parts warehouses, of that model ever having existed.

 

Manufacturers are there to make money from current models, and from the manufacture of new products that provide the latest level of technology and competitiveness - and to produce products that also meet current laws and regulations.

Bean counters are hot on ensuring the minimum level of company funds invested in parts on shelves, and storage in expensive warehouses. Parts deteriorate even after a couple of years in storage, despite good storage conditions and protective measures.

 

Edited February 21, 2023 by onetrack

[spacesailor]

IF an Aussie can\did make a 'world beating ' engine ,IN his home garage  before he ' Tooled up ' to make multiple motors.

WHY so hard for Jabiru !.

But , maybe he folded too.

spacesailor

[RFguy]

It's hard for Jabiru because the people at the top of the company have in my opinion the wrong attitude for making aircraft engines. 

 

Example 1: in Gen3 they went down three push rod lengths before they got it right.  so HUNDREDS of operators have push rods that are too long and head recession that happens causes valves to hang open which ultimately causes valves to drop into the engine. They KNEW this was a problem and didnt say anything. 

I found this on my engine rebuild #1 and I independently determined the pushrods had been too long, and when I called up Jabiru they were like oh yeah, we changed them because of that.

But they didnt tell anyone, nor update anyone......And the service/ maintenance manual is wrong !.......

There should have AT LEAST been a service bulletin issued. That example is one of many and complete and utter BS.  The only thing going for the Jabiru engine is that it is cheap to overhaul at 1000 hours, and parts are inexpensive compared to Rotax and Lycoming. And it is reliable if you never fly the engine with compressions less than 70/80 or 65/80 if you need to fly to service.

 

Fortunately there are good and honest people in the service department to talk to .

 

 

 

Edited February 21, 2023 by RFguy

[skippydiesel]

Back to origional question; Try contacting Dave of "Dave's Flying School" The Oaks, NSW 2570, Mobile 0414740766. Be persistent,  if not answered, leave a message,

[spenaroo]

15 hours ago, onetrack said:

Most manufacturers work on 20 years as the limit to which they will supply parts for their manufactured automotive products. After 20 years, you become reliant on aftermarket suppliers to provide components - and they will only manufacture "fast-moving" parts - the ones that wear out the most.

With Japanese automotive products, the Japanese manufacturers go through the factory warehouse once a product reaches 40 years since introduction - and they grab every single new part and component off the shelves for that model, and send them to scrap - then they dispose of all the factory books, records and blueprints for that product - so effectively, there's no trace in the HQ, factory or parts warehouses, of that model ever having existed.

 

Manufacturers are there to make money from current models, and from the manufacture of new products that provide the latest level of technology and competitiveness - and to produce products that also meet current laws and regulations.

Bean counters are hot on ensuring the minimum level of company funds invested in parts on shelves, and storage in expensive warehouses. Parts deteriorate even after a couple of years in storage, despite good storage conditions and protective measures.

 

I think that is a little outdated,

pretty much every motorcycle manufacturer I worked for had a supported product life span of 10 years.
all reduced down to in the 2010's. realistically after about 5 years it started to be questionable, especially anything out of the ordinary - often waiting till they had a big enough back-order list before they would manufacture the part.

and they didn't scrap the parts, they would sell them in a bulk lot to interested parties.
there are specialist company's that purchase and distribute NOS

this is the company I know Harley uses, looks like Boeing does too
https://www.vpartsinc.com/aviation

[onetrack]

Local companies and American companies may sell their obsolete parts to NOS dealers, but I can assure you, in Japan, the parts are sent to scrap after 40 years. But they recycle all the materials in them that are useable, such as metals.

[facthunter]

One particular Japanese brand had to be forced to carry more spares here by Law. If someone wanted me to work on that brand they had to HAVE the required parts, or I wouldn't take it on, but that has problems as you don't know exactly what you are going to need. I couldn't have stuff in bits sitting around. No one can.  Nev

[jackc]

I am still buying genuine Toyota Landcruiser parts for 40 year old vehicles.