GO JUICE FOR JAB 2200

[rick-p]

Has anyone out there had any problems in running a Jab 2200 0n high octane motor spirit (98 octane mogas) in substitute to that of using Avgas 100ll?

 

Avgas in regional areas in drums is becoming so expensive at around $685.00 a drum one thinks that it is time to consider the upper end of the market quality mogas which 912's use in preference to Avgas because of the adverse effects Avgas has on those engines when used over long periods of time. What I'm looking for is, factual information as to whether or not there were any deficit in the performance of the Jab 2200 when mogas with a 98 or above octane level was used?

 

Also in respect of maintenance, was more maintenance required to the motor and also was there obvious side effects from the use of mogas on the internals of the motor when overhauls or rebuilds of the motor were carried out?

 

The information, if any, provided in answer to this post may well be of great assistance to not just a few but possibly many who are feeling the pinch with the rising Avgas prices.

 

On the other hand it may keep some of us safe!

 

Rick-p

 

 

[facthunter]

I won't direct anyone one way or the other, but... The 912 is designed to run on mogas. Sometimes there is only avgas available. Use it occasionally or as a shandy. and change oil regularly and there should be no problems.

 

The Jabiru recommends avgas LL 100.. Why? well it runs hotter and the lead additive works to help the valves remain seated longer. The motor needs a high octane fuel Also it is a regulated quality product that has to meet higher standards than Mogas. Apparently some Jabiru's have suffered detonation. It's linked by Jabiru to through bolt failures. That makes sense, and later motors have plates fitted below the cylinder flanges to lower the compression ratio and help prevent detonation. So, until Jabiru suggest it is suitable I wouldn't use it. Nev

 

 

[GregF]

I believe this document will give you the answers you are looking for:

 

http://www.jabiru.net.au/Jabachat/Jaba%20Chat%20January%202010.pdf

 

Cheers

 

Greg

 

 

[facthunter]

I won't direct anyone one way or the other, but... The 912 is designed to run on mogas. Sometimes there is only avgas available. Use it occasionally or as a shandy. and change oil regularly and there should be no problems.The Jabiru recommends avgas LL 100.. Why? well it is a hotter running engine and the lead additive works to help the valves remain seated longer. The motor needs a high octane fuel . Also it is a regulated quality product that has to meet higher standards than Mogas. Apparently some Jabiru's have suffered detonation. It's linked by Jabiru to through bolt failures. That makes sense, and later motors have plates fitted below the cylinder flanges to lower the compression ratio and help prevent detonation. So, until Jabiru suggest it is suitable I wouldn't use it. Refer next post link apparently after Jan 2010 they do allow some types of mogas on the later motors...Nev

Don't know why this printed as it did. I meant to amend my previous post. Nev

 

 

[Gnarly Gnu]

The mogas appears to permeate the internal fuel lines somewhat leaving a cockpit that always smells of fuel which doesn't appear to happen with Avgas I understand.

 

 

[Dieselten]

Ran mine on 98 Octane BP Ultimate for a while. Ran beautifully. No detonation problems at all, but very susceptible to carby-icing on humid winter mornings. This was very annoying unless you knew what was going on and took care to clear the carby before takeoff.

 

My 912 Rotax runs on nothing but BP Ultimate. BTW, I have never found alcohol in BP Ultimate. "No-Name" or discount outlets are not selling the same 98-octane product...I found 10% alcohol in 98-octane fuel from "Enhance" in Albion Park Rail. (They clearly state they have alcohol in their fuel, so you can't say you haven't been warned.)

 

IMO the failing through-bolt issue isn't related to fuel octane-rating (and never was), it's related to the old-style (half-height) nuts on the through-bolts. Why else would Jabiru change to a new, longer style of (12-point) nut and increase the length of the through-bolts to accommodate them? If you want to see where the problem is, look for the changes in the replacement parts after the factory has worked on the unit, and ask yourself why there is a service bulletin out about through-bolts and new nuts.

 

Your Jab engine will fun perfectly on 98 Octane fuel as long as it comes from one of the three big brands. I only use the BP product because there are several outlets nearby and it's convenient.

 

It loves Avgas, though.

 

 

[facthunter]

D10, I'm only quoting jabiru who have repeatedly listed detonation as a factor in bolt breakage. The ineffective thread/ nut issue is more of a "tidy-up get it right thing" . Don't forget that lean mixtures detonate easier than rich ones. High head?valve temps make the thing more critical. Nev

 

 

[rick-p]

I believe this document will give you the answers you are looking for:http://www.jabiru.net.au/Jabachat/Jaba Chat January 2010.pdf

Cheers

 

Greg

Thanks friend,

 

I had a read of the the article you suggested and I thank you for the lead.

 

It was very imformative and although a little non committal it basically answered my questions and satisfied my concerns.

 

In a nut shell I would have to say that after reading the article that despite the extra cost of Avgas the same will remain my fuel of choice .

 

In my humble opinion, relying on the information in the article and the posts, on point, here, that Avgas has both in respect of safety and maintenance issues a lot more going for it.

 

At the moment I use Avgas 100 but I may go back to 1ooll.

 

I don't think that I will be using mogas other than in an emergency and then it will be for the most part mixed with some Avgas.

 

Also I wouldn't be putting it in the fuel tank before I had first carried out an Ethanol test.

 

Thanks all for the assistance in this query of mine.

 

Rick-p