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Overhaul at 1195 hours

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Overhaul at 1195 hours

Postby skypics234 » Mon Mar 21, 2016 5:27 pm

Just want to give some kudos to Ben at Jab North America on the overhaul of my 2200 (s/n 3237 at 1195 hours.

The engine was still running great at 1195 hours, but right after giving a seminar to an EAA group at Brown Field in San Diego on emergency landings, and while departing the field, the engine ran very rough and I had to return for a precautionary landing.

After removing the cowl I noticed some oil leaking. The top right stud on the #4 was snapped off and when turning the prop I could feel some resistance on each turn.

Pulled #4 head and found the exhaust seat had come loose and held the exhaust valve open which made a slight ding in the top of the piston, but not enough to bend the rod.

I monitor all temps very well which were always in spec so neither Jab or myself know why this happened.

Since the stud was broken and would require taking the engine apart I sent it to Jab North America and let Ben deal with it.

I am completely satisfied with the service although it took a lot longer than expected because Ben was at Sun N Fun for a week and they had to sent to Aussyland to get a new head which then became held up in customs.

After 1 1/2 months the engine is in and after only 12 hours the oil consumption is way down so I'll run it up to 25 hours and then switch from mineral oil to 20-50 Phillips.

The cost including shipping back and forth was less than $7K.

At my age I suspect this engine will take me to the end of my flying years.

John
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Re: Overhaul at 1195 hours

Postby diablo » Mon Mar 21, 2016 7:48 pm

John ,

That sounds like you have the luck of the Irish ...

Normally, an incident like that can be devastating for an engine and pretty darn dangerous for the pilot. Well done keeping it all under control and getting the aircraft back on the ground safely ! As far as the damage to engine goes, well, you can always fix that.

$7K however seems an awful lot for a top end rebuild. Did you do all of your pots and heads (valves, seats, guides, cylinders and pistons) or was it just a partial ? You would not have been to far off getting a new block for that price!
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Re: Overhaul at 1195 hours

Postby kevin814 » Wed Apr 20, 2016 2:25 am

John,

You might want to consider switching off mineral oil much sooner. The Phillips oil is an ashless dispersant, which does nothing to impede break in. It's advantage is being able to hold dirt and metal particles in suspension (dispersant=dispersal) for the oil filter to catch rather than settling out of the oil in undesired places. In my somewhat humble opinion, the people that recommend running mineral oil for 25 hours have a very poor understanding of oil chemistry, and unnecessary engine wear can be the result. Anti wear additives can slow the break in period slightly, because they reduce wear. These additives are common in most automotive oils, but this isn't an issue for aviation oil which has no metallic antiwear or auto style additives.

I've been an oil geek for quite a few years, but you can search on Google to back up what I'm saying. Camit recommends running mineral oil no more than 5 hours before switching over, and that's what I did after my top end rebuild. I'm about 35 hours post rebuild now, and I burn/lose about 2 ounces every 10 hours. The oil I'm currently using is not generally recommended for aircraft, but in my specific situation it works very well. As the season heats up, I'll be switching to Phillips w/Camguard. Everything is a compromise, but I believe this will be the best solution for me. I've spoken with the former Exxon aviation oil R&D chief, and I wish I had a tape recorder. So much valuable information, but my brain only retained a small portion of it, and it was like reading Shakespeare to a rock :lol: I also trust everything Ian at Camit says, a very smart and honest guy.

I'm glad to hear your engine is running well. I hope you get many trouble free years.

Kevin K.
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Re: Overhaul at 1195 hours

Postby kevin814 » Wed Apr 20, 2016 12:14 pm

I forgot to post this link last night. Mike Busch also has some very good webinars on the EAA website which are free.

http://www.swaviator.com/html/issueja02/Hangar7802.html


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Re: Overhaul at 1195 hours

Postby Russ » Thu Apr 21, 2016 5:55 am

myself and a growing number of guys, use and swear by upper cyl lube added to fuel. Moreys is the most used, but there are others also....lucas is one.

i sent a mail off to moreys, seeking comments about possible lessening of octane rate ( RON )......they were adamant, no effect..period.

just sayin here, no direction inferred.
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Re: Overhaul at 1195 hours

Postby kevin814 » Fri Apr 22, 2016 9:29 pm

Hi Russ,

I haven't heard of Morey's before, you made me curious. I just looked at the MSDS, says Hydrotreated light naphthenic distillate (less than 60%) , flashpoint 200c, boiling point 300c, evaporation point= less than either. Based on the above specs, to me it sounds like a blend of petroleum oil, and solvent. It reminds me of Marvel Mystery Oil, but probably doesn't have pig fat or perfume added. I think based on the laws of physics, unless they add some type of special octane booster, the product would certainly lower the octane rating of the fuel. At the recommended dosage, it might not be significant though.

Before I modified my high octane combustion chambers, and cleaned the carbon from the heads and piston my engine was very sensitive to detonation. If I added a little bit of Sea Foam, or Techron it would detonate during climb out. Even using Decalin to counteract the lead caused detonation, and by all accounts this should not have caused detonation since it's used by many and is approved for aircraft. My engine used to be a good diagnostic tool for the octane lowering effects of additives, fortunately that has changed ;)

Since burning petroleum causes carbon, and longer chain oil molecules make even more carbon, I think this might increase the carbon production of your engine. The solvent may help to mitigate this, but it's still about 40% oil. This may help slightly with intake valve/seat wear (which doesn't seem to be much of a problem on our engines) but it's doubtful it would benefit the more troublesome exhaust valve and seat, since at that point it's just carbon laden smoke. Exhaust valves work best with clean metal to metal contact of the seat to transfer heat from the valve to the head. Carbon also builds up on the exhaust valve stem while it's open, then gets rubbed into the valve guide as it closes, causing wear and increasing the odds of a stuck valve. That's why I'm also leery of 2 cycle oil. The engines it's designed for don't have valve stems to contend with, and will it get along with the motor oil in the ring lands, which is exposed to high heat.

I don't want to come across as someone who poo poo's other people's ideas. I'm a very positive person, really :D This might be a great product, and the fact that there are so many satisfied customers speaks a lot for it. Just food for thought, as I try to visualize any potential downside. I'm just regurgitating some of the information I've absorbed over the years from reputable sources, so I'll play devils advocate. The benefits could easily outweigh any risks, and upper cylinder wear is an important thing to consider.

I believe our engines could benefit from better cooling of the bottom side of the cylinders. Most installations cool the top and sides, but the very bottom just bakes, which is detrimental to the cylinder and rings in that area, and makes the oil there much more likely to stick the rings.

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Re: Overhaul at 1195 hours

Postby jetjr » Sun Apr 24, 2016 10:16 am

CAE squirt oil under pistons I believe
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Re: Overhaul at 1195 hours

Postby Russ » Sun Apr 24, 2016 9:50 pm

My "reply" seems to have gone into cyber space.........gawn

OK....went something like this......chap that put me onto UCL is a petro chemist here, biggest refinery Oz, he approved the use, said another way was to add 2 stroke oil ( he does this method to his jab )

I.....and many guys, have seen/ witnessed positive results using UCL ( moreys, in particular ).....one chap knew he was developing a sticky valve when CHT went higher, he would nurse the situation ( silly bugger ).....anyway he tried UCL........problem gone. I expected him to pull heads off and address the valve, but he's happy to now leave it.

Ive seen heads when removed after using UCL......clean as, any carbon residue is soft, actually wipes off with your fingers. Everything looks pristine. So this is my own experiences.

cheers....russ
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Re: Overhaul at 1195 hours

Postby kevin814 » Mon Apr 25, 2016 11:53 am

It sounds like a good product. Stuck valves is one of the things I worry about, and I'm all for increasing reliability where we can.

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Re: Overhaul at 1195 hours

Postby Garyo » Tue Apr 26, 2016 7:16 pm

The tiger and auster old boys at felthorpe uk use motorcycle scooter 2T oil in their petrol to prevent carbon build up on the valve stems of the gipsy engines, i dont know the ratio, will ask but thinking of adding this to my fuel as well. I have 2 old school 2T bikes, the motors are clean as a whistle with synthetic 2T oil, castrol power 2T not cheap at £15 per ltr as apposed to asda price stuff about £3 per ltr.
When you read the labels they have the same tested too data, so i dont know if its label selling or something i am missing
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