Has anyone done a top overhaul on their Jabiru 2200 / 3300 ?

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Marc W

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I am pondering the same question. My Gen1 Jabiru 3300 has 760 hours. Compressions are good and it doesn't use oil but the 1000 hour top overhaul is looming. Mine has cooling system issues that I have spent a lot of time on to get worked out and not quite there yet. The nagging question is: is it worth it to keep spending time and money on this engine?

Do you have the OH manual? If not, download it here: Manuals - Jabiru The Aussie forums are a good resource for info also.

I am surprised that valves are not on the parts list. I thought valves were a "must replace" item. They have an improved valve made from better material now.
 

Map

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I think your engine is just fine.
An oil cooler with a NACA inlet on the side of the cowling does not work well on any airplane (compared to how well it could work with a ram air inlet). I have had multiple customers with the same issue.
Attach a small scoop to the outside to direct more air into the NACA inlet, that will help. Start with the scoop sticking out from the cowling surface at least 2". It can be made from sheet metal and taped on for tests (aluminum tape). Change the size as needed.
That the oil turns black after 10 hours is normal. Is the calibration of your oil dipstick correct? Maybe you are overfilling it. That it maintains the same level after it is at the lower limit is a good sign, it is not burning much oil. If the compression and performance are consistently good, there is no need for an overhaul.
Cooling issues are a lot cheaper and easier to resolve than an engine overhaul, which will not resolve cooling issues. Anyone with engine cooling problems should contact me or read my book "Efficient Powerplant Installation" which has a lot of information on engine cooling.
After my engine cooling forum in Oshkosh, one guy in the audience who listened to my advice, was able to get his hottest cylinder, which had been bothering him for a long time, down by 40F to where the rest of the CHT was with a simple baffling change.
 

Vigilant1

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I think your engine is just fine.
An oil cooler with a NACA inlet on the side of the cowling does not work well on any airplane (compared to how well it could work with a ram air inlet). I have had multiple customers with the same issue.
Attach a small scoop to the outside to direct more air into the NACA inlet, that will help. Start with the scoop sticking out from the cowling surface at least 2". It can be made from sheet metal and taped on for tests (aluminum tape). Change the size as needed.
That the oil turns black after 10 hours is normal. Is the calibration of your oil dipstick correct? Maybe you are overfilling it. That it maintains the same level after it is at the lower limit is a good sign, it is not burning much oil. If the compression and performance are consistently good, there is no need for an overhaul.
Cooling issues are a lot cheaper and easier to resolve than an engine overhaul, which will not resolve cooling issues. Anyone with engine cooling problems should contact me or read my book "Efficient Powerplant Installation" which has a lot of information on engine cooling.
After my engine cooling forum in Oshkosh, one guy in the audience who listened to my advice, was able to get his hottest cylinder, which had been bothering him for a long time, down by 40F to where the rest of the CHT was with a simple baffling change.
+1

Is the stock oil cooling system working well for others? (Doesn't sound like it based on the POH note). A NACA duct looks high tech and is a good way to bring in a little bit of air at minimal drag penalty. It is not a good way to bring in a lot of air at sufficient pressure to feed it through an oil cooler.

1662819453363.png
MAP's idea posted above sounds very reasonable. Yes, do a compression check and other simple things to assure the engine is healthy, but then directly address the problem you know about: high oil temps. You might eventually need a bigger oil cooler, but I'd first do everything practical to bring in enough air and assure the pressure gradients are right throughout the ducting so that enough air flows through the existing oil cooler.

For the existing noted problem (high oil temps in climb), I'd check/improve the air supply (amount and pressure) through the oil cooler first. Then, if needed, upgrade the oil cooler. Opening the engine to fix an oil temp issue would be way down my list.
 
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TFF

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I agree that I wouldn’t touch it from the first. Especially with time left. Your problem isn’t the engine but satisfying the CFI.

I said either new small or upgrade. New small is in the quote. You might have been given a quote from Jab, but don’t think you weren’t going to be getting the call for the upgrade. Especially if they see case fretting.

With the documentation, I would not top a small stud Jab. Not without splitting the case for new studs. If it was a big stud, yea; at least it looks like more success. The Jab is stuck between being a VW and a Lycoming. The goods have always been comparable. What you are getting is an overlap of the bads.
 

KeithO

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Another FWIW, there’s a CH750 builder/ flew up at Mason (KTEW) with a 3300 Jabiru. Might track him down and compare notes.
The 750 is a slow plane and therefore the cooling is addressed in a way that cant be replicated on a 130kt plane. I do think the cooling on the Lightning is marginal at best (for the oil cooler) but changing it will probably require a new cowling. May need to delete the muffler because that adds a considerable heat load under the cowl and is in the way of the prime location for an effective oil cooler location cooled by air blast. If I added fuel injection I could get rid of the entire carb heat system and if I added modern engine controls I could get rid of both distributors and have variable timing which would make the engine run better. I just question whether the base engine is robust enough to justify spending money on it. If I was to use only unleaded gasoline going forward perhaps the lead sludge problems would be eliminated and the oil change interval could be longer.

At the same time I imagine that everything could be a lot cheaper and simpler and all of the inherent issues would be gone if I went with a Viking or other Honda engine package instead. Thus why I have been reluctant to make any changes to the current Jabiru installation.
 
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Geraldc

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With the Jabiru if you use/copy the factory nose bowl and motor baffling you should have no cooling issues.
1662843109883.png
 

KeithO

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Does the Jabiru have a front mounted oil cooler ? Is that what the lower intake is for in the cowling ? Or is it for sump cooling ?
 

KeithO

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With the Jabiru if you use/copy the factory nose bowl and motor baffling you should have no cooling issues.
View attachment 129688
1662846519278.png
The Naca duct on the side of the cowling is for the oil cooler and the tiny opening below the spinner is for the air feed to cool the sump. This is on the LS-1 SLSA (factory built, ASTM certified light sport plane). Anyone who owns one of these has no legal option to change any detail relating to the oil cooler.
1662846752056.png
View behind the cowling showing naca duct intake to oil cooler front face.
 

Vigilant1

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View attachment 129693 This is on the LS-1 SLSA (factory built, ASTM certified light sport plane). Anyone who owns one of these has no legal option to change any detail relating to the oil cooler.
View attachment 129694
View behind the cowling showing naca duct intake to oil cooler front face.
If I knew someone who owned one and it had oil cooling problems, I'd recommend that he fabricate a homebrew ram air scoop in about 30 seconds, put it over that NACA opening, and see how the oil temps looked in a climb. And seal up any existing gaps or holes in the ducting (a small leak can make a surprising difference).
 

KeithO

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If I knew someone who owned one and it had oil cooling problems, I'd recommend that he fabricate a homebrew ram air scoop in about 30 seconds, put it over that NACA opening, and see how the oil temps looked in a climb. And seal up any existing gaps or holes in the ducting (a small leak can make a surprising difference).
It definitely seems that adding an external scoop is the first thing to do.
 

TFF

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It doesn’t look like the cooler is sealed at the top. Bead of RTV filling that in top and bottom will help some. That’s a no harm thing done on all certified planes. Same with any gaps at the engine baffles. Engine runs cooler, oil cooled does less work.
 

Vigilant1

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Looking at the picture, depending on the existing pressure behind the oil cooler, there might be a little increased flow through the oil cooler to be gained with a smooth exit duct (nice radiused turn, generous duct area) and an exit with a lip in the airflow. Anything to reduce pressure at the back of the oil cooler.

But the bigger gains will come at the front, turning dynamic pressure into adequate static pressure (and flow) at the face of the oil cooler.
 
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Marc W

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This is what I did with my 3300 to cool the oil. First, large 13 row cooler. Entry duct from front of cowl and exit duct with flap to shut off airflow for winter flying. The configuration has changed from the picture due to removing the muffler and gaining more space under the engine. Both entry and exit ducts are larger now.
Tail Pipes.jpg
 

Pops

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On the SSSC at first I had a NACA duct on each side of the cowl and each had a hose to the oil cooler. Not enough air to make any difference. Then went to the 2 scat hose to the rear of the cylinder scoops. Huge difference in the amount of air. Now if the AOT's are 70 degs or below I unhook one.
 

PMD

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Keith: I would not disturb an engine that you have not first diagnosed and verified that it NEEDS to be disturbed.

Compression testing by both leakdown and dynamic (cranking), listening for leakage into crankcase (there WILL be some) or valves start at end of induction and exhaust first, but if you get curious remove manifolding and listed at ports. These are basic diagnostics 101. If nothing there, LEAVE IT ALONE.

In an engine design with some kind of valve binding history, just take a feeler gauge between the spring coils at full valve lift to make sure you have some room left. What you are saying about valves is not "grinding" them at all, it is lapping. Usually a waste of time. If you really want good valve seats, the work is done with carbide cutters with fixed angles. The valves themselves you grind - but again, if nothing is leaking and the guides are not sloppy, leave them alone.

You also were worrying about mounting by the prop flange and spinning a bearing while doing a top overhaul. I have yet to see any engine that requires you to split the crankcase to work on the cylinders, pistons and rods. The bearings you are worried about are the mains, and they will remain clamped.

Finally, what people are saying about random mechanics is true of many random mechanics and well-intended owners and engineers. Each engine design has a LOT of little detail stuff that you really need to know and practice at to get right. If an engineering degree was what it takes to deal with this, those problems wouldn't BE there in the first place. If you were on engine #50 or so, you MIGHT be fine to switch to a different design, but reality is there is a lot of things you need to pick up from experience that can not necessarily be puzzled out in a single session. The advice to go to the company that teaches this particular engine is by far the best in this thread.
 

KeithO

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This is what I did with my 3300 to cool the oil. First, large 13 row cooler. Entry duct from front of cowl and exit duct with flap to shut off airflow for winter flying. The configuration has changed from the picture due to removing the muffler and gaining more space under the engine. Both entry and exit ducts are larger now.
View attachment 129703
What airplane is this ? I mentioned in one of my earlier posts that in order to fit an oil cooler "up front" I would need to remove the muffler as you did. But Im pretty sure my cowling is too shallow for the setup above, I would need to go with a wider and shorter cooler given the space constraints. Have you lost your heater in this process ? I would need a heater for half the year so I would need a solution for that.
 

KeithO

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Keith: I would not disturb an engine that you have not first diagnosed and verified that it NEEDS to be disturbed.

Compression testing by both leakdown and dynamic (cranking), listening for leakage into crankcase (there WILL be some) or valves start at end of induction and exhaust first, but if you get curious remove manifolding and listed at ports. These are basic diagnostics 101. If nothing there, LEAVE IT ALONE.

In an engine design with some kind of valve binding history, just take a feeler gauge between the spring coils at full valve lift to make sure you have some room left. What you are saying about valves is not "grinding" them at all, it is lapping. Usually a waste of time. If you really want good valve seats, the work is done with carbide cutters with fixed angles. The valves themselves you grind - but again, if nothing is leaking and the guides are not sloppy, leave them alone.

You also were worrying about mounting by the prop flange and spinning a bearing while doing a top overhaul. I have yet to see any engine that requires you to split the crankcase to work on the cylinders, pistons and rods. The bearings you are worried about are the mains, and they will remain clamped.

Finally, what people are saying about random mechanics is true of many random mechanics and well-intended owners and engineers. Each engine design has a LOT of little detail stuff that you really need to know and practice at to get right. If an engineering degree was what it takes to deal with this, those problems wouldn't BE there in the first place. If you were on engine #50 or so, you MIGHT be fine to switch to a different design, but reality is there is a lot of things you need to pick up from experience that can not necessarily be puzzled out in a single session. The advice to go to the company that teaches this particular engine is by far the best in this thread.
PMD, great advice. Honestly, if I can sort out the oil temperature issues I will leave it at that. The external scoop will be pretty straight forward and perhaps it is enough by itself. Removing the muffler and doing the direct blast cooling with the oil cooler in front is a much bigger job, especially if I will need to retain carb heat and the cabin heat solutions. If Aeromomentum finally comes through on their new gearbox in 2023 then I should be able to put together a new FWF system with a new more robust front landing gear and that would check a lot of boxes on my wishlist. Then I can sell the unmolested Jab to someone else...
 

Marc W

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Rans S-7. Much slower than your airplane so harder to cool. I did lose the cabin heat. I found that with the heat from the firewall and the floor that I was still comfortable in winter. This is what my cowl looks like now.

Oil Cooler Duct.jpg
 
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