Jab 2200 Gen 4 installation

11 posts in this topic

Posted

The Gen 4 engine on my Avid MK4 has actually flown 1st flight.

Finally, I have the air dams modified to fit under my cowl. Of course. My cowl is tight so if you have a different shaped cowl you may not have to do anything.
 
The one thing I would suggest to Jabiru is to add a few inches length to the plug wires. At their present length, it is very difficult to connect to the plugs because you have to keep the dam close to the head and get your hand up under the dam to connect the wires.
 
The 1st time I fired up the engine, the float bowl leaked due to contamination preventing the float bowl from closing. I could see debris in the bottom of the bowl. Got that issue resolved...I thought. Then I took it for the 1st flight and the engine sputtered and threatened to die at 50 up. So I slipped it down safely.
 
Found more debris in the float bowl so, with the bowl removed I cranked the engine which flushed all the debris out of the fuel line. I think the debris was from when I cut into the line between the fuel pump and the carb to install the line to my fuel pressure sensor.
 
Did a couple of crow hops with no issues so I flew a couple of full patterns.
 
All pressures and temp readings were well within specs and the engine performed flawlessly. Actually, the EGTs and CHTYs are lower than that on the old engine. The fuel pressure runs between 4-4.5 PSI so I had to change the upper limit alarm on my Grand Rapids EFIS.
 
It can idle all the way down to 600 RPM very smoothly. 
 
I have the prop set at the same degrees as when I pulled the old engine to see if there would be any difference in climb RPM. There is no difference. Climb RPM at 65 MPH is 2850. I expect this may increase a bit with the engine is finally broken in. 
 
I only have 1 hour now. I'll update when I have more hours and consider it broken it.
 
So I'll be flying patterns for several hours.
 
John M
 

;t go into the details of the mod.

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Posted

Thank you for the update. We would love to see photos of your install. 

 

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Posted (edited)

I had to add more pitch in the 2 blade Whirlwind prop due to extra power. This boosted my cruise about 5 MPH, but I still have a great climb.

Number 2 CHT is 50 F higher than the rest which are around 300F in cruise. Number 2 would get up to around 350 F. 

I had to cut the air dam in front of the cylinder to half the height and that corrected that issue.

I have flown 6 hours so far and other than a small leak, due to the oil filter no tight enough, the engine uses no oil as compared to the older Gen 2 engine. There is only a tiny amount of oil and water at the bottom of my air/oil recovery bottle.

As you all know, it was impossible to start these engines by propping, but since this engine starts quickly, even without using the choke, I suspect it might be possible to hand prop a start. I just touch the starter button and it starts instantly and can tick over at a low 700 RPM.

As mentioned before, I had to cut down the top of the air ducts to fit under my cowl.  I actually prefer the older air ducts where the plug wires are on the outside. I believe it is not a good idea to have the plug wires laying inside the air duct to be subjected to all that heat and disturbing the air flow.

On my older Gen 2, I measured CHTs with a thermocouple junction down inside the head in the hole between the plugs and sealed it with RTV. This engine has those holes threaded and I had to crimp small lugs on the thermocouple and screw them to the head.

More to come....

Edited by skypics

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Posted

And the frustration goes on...

Try as I might, I can't get the #2 CHTs to fall in line with the rest. It runs 350 F in cruise at 2800 RPM while the rest run 300 +/- 5 degrees. The EGT is 100 higher than the next highest also. It reads 1280 F which is within spec. This is with OATs at 70 F.

I have eliminated the thermocouple and the Grand Rapids EFIS as the issue and have cut the air dam in front of #2 down as low as I can with no resolution to the problem.

I have asked Nick at Jab Tennessee for a resolution and am awaiting his response.

Any ideas from this group are appreciated.

John M

 

 

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Posted

That's the main reason VW and others finally got out of the air cooled engine market and went water cooled. It was too hard to balance out heat issues

I've got an old 63 Harley that I have owned for many decades and the back cylinders always run hotter on them. The bandage fix on the Harley has always been to run a cooler plug in the back and then monitor plug color to match them up. It's even listed in the old manuals to do so. I'm not suggesting that's a fix to your problem, just pointing out how one brand of air cooled engines dealt with the problem.

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Posted

That's the main reason VW and others finally got out of the air cooled engine market and went water cooled. It was too hard to balance out heat issues

I've got an old 63 Harley that I have owned for many decades and the back cylinders always run hotter on them. The bandage fix on the Harley has always been to run a cooler plug in the back and then monitor plug color to match them up. It's even listed in the old manuals to do so. I'm not suggesting that's a fix to your problem, just pointing out how one brand of air cooled engines dealt with the problem.

On the Jabiru, the number 2 cylinder is one of the front ones.  I was having high CHT temps on my # 3 (rear) cylinder on my Jabiru, and finally swapped the probes from # 1 to # 3.  Now # 1 is the hot cylinder, so I figured it was the thermocouple, not the cylinder.  As far as getting temps down John, all I can suggest is to make sure the air dams are sealed as good as possible to the cowl, so you don't loose any air, but it's forced through the air dams.  JImChuk

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Posted

That's the main reason VW and others finally got out of the air cooled engine market and went water cooled. It was too hard to balance out heat issues

I've got an old 63 Harley that I have owned for many decades and the back cylinders always run hotter on them. The bandage fix on the Harley has always been to run a cooler plug in the back and then monitor plug color to match them up. It's even listed in the old manuals to do so. I'm not suggesting that's a fix to your problem, just pointing out how one brand of air cooled engines dealt with the problem.

On the Jabiru, the number 2 cylinder is one of the front ones.  I was having high CHT temps on my # 3 (rear) cylinder on my Jabiru, and finally swapped the probes from # 1 to # 3.  Now # 1 is the hot cylinder, so I figured it was the thermocouple, not the cylinder.  As far as getting temps down John, all I can suggest is to make sure the air dams are sealed as good as possible to the cowl, so you don't loose any air, but it's forced through the air dams.  JImChuk

Well that changes the problem. Is this a carburetor or fuel injection system? If the air dams are setup correctly your next possible cause may be the front cylinder running lean either from a carburetor adjustment or a possible air leak around the intake manifold or carburetor for that cylinder. Another Harley manual suggestion was to squirt gas around the carburetor manifold joints at idle and listen for an increase in RPM. Probably not in the modern manuals for fire hazard reasons but it's printed in mine. If you get an increase you found your leak. I'd check the plugs first for an indicator if the front is running hotter from fuel/air mixture issues.

If you can't let more air into the front cylinder; can you baffle off some of the air going to the rear? You may be able to force more air to the front by restricting it more to the back. Just guessing here as I have no idea how your baffles are setup.

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Posted

After speaking with Nick Otterback of Jabiru Tennessee I found that I had not installed the #2 air dam correctly. 

It should be flat against the cylinder or else the air flow can dive down under the cylinder instead of over the top.

After reconfiguring the dam the temp on #2 CHT is now the 2nd lowest running around 300 F in cruise.

I had to do a LOT of modification on the Air duct to fit under my cowl. Looks like crap now after the modification, but I'll clean it up and apply some paint and it will look better.

As long it is cooling all cylinders it's not that important.

Engine runs strong and so smooth.

It starts instantly at 1st run up in the morning without using the choke.

I am starting to suspect this engine could be hand propped if necessary.

It seems to use very little oil.

I changed from the mineral break-in oil at 7 hours but was told by Jabiru that I should run the break-in oil for 25 hours. So I drained the 20-50 and reinstalled the mineral oil.

This engine should take me to the end of my flying days.

John M

 

 

 

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Posted

No matter what brand of engine your flying behind; great support will set them apart from the rest of the pack. It sounds like a great support team.

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Posted (edited)

I now have 18 hours on the new Jab 2200 Gen 4.

I am pleased to report that this engine has been redesigned to correct the deficiencies in the top end lubrication.

All CHTs read 290 F +/- 30 F in cruise. EGTs are 1200-1250 F.

This engine is smooth and is putting out more power than the Gen 2 I had. 

Since I repositioned the air dams in front of the front cylinders so that the dams lay against the fins, the temps are all good. Such a simple fix.

Have never seen the necessity to add water cooling to add weight and complexity to a simple engine. My Rotax 912 friends have had to deal with radiator issues and water leakage.

Jabiru says to run mineral oil for the 1st 25 hours, but I have read other break-in articles that recommend Phillips 20-50 oil during break-in. I will be changing the oil when I return from my annual Idaho backcountry trip.

This engine seems to use no oil. I have been running the oil level at the top mark of the dip stick and it doesn't blow out any oil into the air/oil separator. 

I will try to do a hand prop soon. I think I can hand start it which would be a benefit if, leaving the master on while in the backcountry strips. Nice to have that option.

I am still amazed at how slow it can idle. I've had it down to 600 RPM.

Jabiru used to claim 85 HP on the earlier engines, but now that claim 80 HP which makes more sense the 3300 with 2 more cylinders come in at 120 HP. 

Fly safely.

John M

 

 

Edited by skypics

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Posted

Everything is still working well on the new Jab 2200 Gen 4 engine.

I changed from straight mineral oil at 17 hours. I was surprised to see the oil still looks clean. I filled to full with Phillips 20-50 XC oil.

I haven't detected any oil usage in 17 hours. 

Was having heating issues with number 2 until I corrected the placement of the air dam. Now #1 is a bit higher than #2 but only runs 310 in cruise in 85 F OAT.

Pilots on my field say the engine sounds great on take off. I use a 66" Whirlwind 2-blade prop with the scimitar-shaped blades which is supposed to be quieter.

The 2200 is a good match for my Avid MK4. 

So far...so good.

 

John M

 

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