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Posted

I wouldn't kno what octane I was running when I had a detonation problem, but it was the top Caltex grade supposedly. I don't have EGT on the corby so there may well be mixture variations and I would be very surprised if there were'nt.

 

I now get fuel at Old Station and the price is better now than it was 6 months ago. They have a large tank in a fully sealed shed. no chance of condensation and as it is above groung Ronnie checks for water So far none found.

 

 

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Posted
The general evidence keeps pointing to detonation. No-one has ever mentioned plug heat range. Fuel quality could be the culprit in some situations. There is no real regulation of mogas whereas avgas is a controlled product. There is an extra risk using avgas. Mixture distribution seems to be a common problem with EGT variance being common as a result. A lean mixture behaves as if the octane rating is lower. That is why take-off power is set up rich. If you have one lean cylinder it may cause damage. The hotter running engines would be more susceptible. Exhaust valves run red hot at high power and could be a factor in detonation.Is everyone running 98 ? Nev

Your observations are extremely interesting Nev because of some certain conversations I had with a Level 2 yesterday and also your advice to me re some upper cylinder lube in the avgas was also raised by him, first.

 

I'm following it up beause the Jabiru motors in the Philippines are only to the best of my knowledge run on 98 ron mogas.

 

Also I was given some other jets to use to increase fuel flow but never used them because after a lot of reading and discussion with Jabiru the important issue, as you have raised, is EGT and if it is within the appropriate heat range then you don't need bigger jets.

 

Rick-p

 

 

Posted
Your observations are extremely interesting Nev because of some certain conversations I had with a Level 2 yesterday and also your advice to me re some upper cylinder lube in the avgas was also raised by him, first.I'm following it up beause the Jabiru motors in the Philippines are only to the best of my knowledge run on 98 ron mogas.

Also I was given some other jets to use to increase fuel flow but never used them because after a lot of reading and discussion with Jabiru the important issue, as you have raised, is EGT and if it is within the appropriate heat range then you don't need bigger jets.

 

Rick-p

Posted

Rick, i have looked thru most comment,s re jab engine . Have there been any comment's posted by Jabiru?, i would be interested in what they have to say with the numerous failures that have plaqued this engine over so many years , and still not resolved.I have done a lot of research my self since i would like to see an ausie engine make the grade. I believe i have found the smoking gun, which i am 100% sure is responsible for 9o% of problems like thru bolts breaking, excessive brg. wear, flywheel bolts coming loose , heating problems, high fuel use. detonation problems , high ring loading causing prem. ring wear,problems relating to head seal leak's, head bolt problems, prop. hub problem's etc. ALL caused by one simple easy to fix low cost solution and this simple oversight would be embarrasing to jabiru factory. I can't elaborate any further at this stage because it would be to hard to ex plain why this is happening , in this post. allso i need to contact jab.first to see if they will listen to me , and i need to verify some other details.

 

I have been a engine reconditioner since 1976 and involved in speedway with many successful engine build's with 4 state titles and many other major win's

 

All the post's [ not including valve related problem's, that's another issue which i'm still looking at]don't go any where neer to the actual cause.

 

if you would like to contact me you could by email [email protected]

 

 

Posted

whats happened with this thread, look's like an engine failure . thrue bolts snapted, prop come off, what!.I'V had a lot of response via email several l2's and owners , even a law firm from usa.

 

 

Posted
whats happened with this thread, look's like an engine failure . thrue bolts snapted, prop come off, what!.I'V had a lot of response via email several l2's and owners , even a law firm from usa.

Well please are you going to enlighten us because I know without a doubt that there are many interested parties floating in the wings waiting for a break through on this subject?

 

 

Posted
Don't hold your breath, Rick-p.

A bit of patience gentlemen. There are pending revelations from that little ole WA country boy that will ring around the aviation world. Thou shalt be in absolute awe, I promise.

 

 

Posted

I'm waiting with baited breath I can assure you because I have been waiting for years for someone to come up with the right answers!

 

I do know of one very smart gentleman who re-engineered his Jab 2200 increasing power output and it would appear relaibility.He ran his motor in a Jodel problem free for many hours, some of you out there who live down around or fly around the Gatton area will know who I am talking about.

 

I really do hope Demech does have some real answers to the problem.

 

Rick-p

 

 

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Posted

Sh!t US Jabiru owners say:

 

Only wish Jabiru was worth the effort. At 83 hours I have exhaust crud in 5 rocker boxes, 6th is still clean as new. I read this as having gotten mixed lot of correct and over-sized valve guides. Waiting for local AP to return from vacation before digging further.

 

 

Posted

Oh well I guess good things come to those who wait! 008_roflmao.gif.692a1fa1bc264885482c2a384583e343.gif It's like Christmas it's coming but never seems to get here until it's been and gone and the cycle once again, starts. 085_blah_blah.gif.5dd1f55e9e017c1ed039995789e61c55.gif

 

 

Posted

Speaking of oil filters I've picked up some Repco ROF21 now that the gen-4 Ryco ones look a bit shoddy.

 

Used to be that Repco stocked both Ryco and their home brand, and at that time both filters were made by GUD SA, the only difference being colour and a $.

 

The ROF21, which also bears Z386 as equivalent on the can, looks identical inside to the Rycos I used a couple of versions back and I had no issues with those.

 

and they are used on many Toyotas such as RAV-4.

 

was there a new recommendation for oil coming out "soon" - or have I missed that announcement?

 

Still holding my breath with Rick-P on the other revelation further up this thread.....

 

Ralph

 

 

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Posted
Speaking of oil filters I've picked up some Repco ROF21 now that the gen-4 Ryco ones look a bit shoddy.Used to be that Repco stocked both Ryco and their home brand, and at that time both filters were made by GUD SA, the only difference being colour and a $.

 

The ROF21, which also bears Z386 as equivalent on the can, looks identical inside to the Rycos I used a couple of versions back and I had no issues with those.

 

and they are used on many Toyotas such as RAV-4.

 

was there a new recommendation for oil coming out "soon" - or have I missed that announcement?

 

Still holding my breath with Rick-P on the other revelation further up this thread.....

 

Ralph

Hi Ralph,

 

There is a Ryco platinum version in the Ryco Z386 but first, it doesn't specfically say on the box that it has a drain back valve also it is a very, what would I say, restrictive filter. It has a 99.9% effective filtering rate and can't be used on racing enginges and must be changed at 5,000 k's or the equivalent in hours. Whet I'm wondering if in fact it would effect the oil flow in the Jabiru motor to the extent of being in detrimental to the motor. I have found the Repco filters ok and the Z386's of which I purchased quite a few of some 6 years ago and am now down to my last one.

 

 

Posted

Jetboy & Rick-p

 

I have spoken to one of the guys over in WA about the modification they have done to the motor. They are keeping this info very close to their chests and have not told me exactly what it is but they will have about 50 hrs on the motor by the end of this weekend.

 

Time will tell how this goes so until they do more hours and check the results we will have to keep waiting.

 

As for the oil nothing has changed here. Still using the Aeroshell 100W plus for the solid lifter motors and the aeroshell multi grade for the hydraulics.

 

Safe flying

 

JabSP6

 

 

Guest Maj Millard
Posted

A little dicky bird has told me that testing has/is being carried out by Shell, both in Europe and Australia testing Jabs with another commonly used oil for 912s. The performance difference and reliability has increased dramically over the currently oil recommended by Jab. Unfortunatly I am in the loop, but sworn to secrecy also, until Shell is happy. Thats all I know ATM.................................................................Maj...024_cool.gif.7a88a3168ebd868f5549631161e2b369.gif

 

 

Posted

Go on Maj, give us the good oil. I can see how one can draw conclusions about performance, but reliability requires many hours and many samples! We could be waiting an eternity if you don't spill..... the beans...............Bob

 

 

Posted
A little dicky bird has told me that testing has/is being carried out by Shell, both in Europe and Australia testing Jabs with another commonly used oil for 912s. The performance difference and reliability has increased dramically over the currently oil recommended by Jab. Unfortunatly I am in the loop, but sworn to secrecy also, until Shell is happy. Thats all I know ATM.................................................................Maj...024_cool.gif.7a88a3168ebd868f5549631161e2b369.gif

this reminds me of a lot of discussion in the 70s about the "good oil" for Ducati v-twin motors, said to be sensitive to the correct oil. As someone said at the time "I put any old oil in my Honda four and it just runs fine". The problem wasn't the oil, it was design deficiencies in the Duke engine.

 

 

Posted

It always ran fine for me in the Datsun 120Y so maybe it's just mass hysteria 029_crazy.gif.9816c6ae32645165a9f09f734746de5f.gif

 

 

Posted
... Still using the Aeroshell 100W plus for the solid lifter motors and the aeroshell multi grade for the hydraulics...

That's news to me. I have hydraulic lifters and have not been told they need different oil. Can anyone elaborate?

 

 

Posted

" That's news to me. I have hydraulic lifters and have not been told they need different oil. Can anyone elaborate? "

 

Nothing changed OK . Aeroshell15w50 or equivalent still the recommended oil for your engine .

 

Bob

 

 

Posted

Old Koreelah

 

The hydraulic motors have always recommended Aeroshell 15w50 or equivalent as Biggles has mentioned. Depending on the climate the solid lifter motors are recommended to use Aeroshell 100w plus but in colder climate you can use Aeroshell 15w50 in them as we'll.

 

Sorry to cause any confusion when I used the words Aeroshell Multigrade. It is just Aeroshell 15w50.

 

Safe flying

 

JabSP6

 

 

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