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I upgraded my STOL 750 to a Jab 3300 Gen 4 earlier this year. I found this engine very easy to cool (both cylinders and oil) which was quite a different experience from the Gen 2 it replaced - the Gen 2 required tweaks and mods to both cylinder and oil cooling but in fairness, when you stuff an air-cooled, 6 cylinder engine in a high-drag/low speed airframe, it can be challenging! I was able to use the Gen 4 ram air ducts as supplied with absolutely no mods/trimming of the diverter vanes inside. (I did have to modify the ram air ducts opening to accommodate my "old style" or original cowl design.) Also, I was able to use a 7-row oil cooler rather than the Gen 2's 10-row. (BTW, it's considered best practice to always install a new oil cooler with a new engine installation. If you attempt to clean and re-use a used cooler, there's always the possibility that the cleaning process may remove material sufficient to uncover a weakened area and cause leaks.)
However, I did have one annoying problem. From day one, there was a very slight oil leak from the front crankshaft seal. It was not serious at all - perhaps just a drop or two of oil seepage per hour of flight. I understand that these engines are run through a break-in sequence on a dyno before shipment, so I don't understand why this wasn't caught then.
I did promptly notify Nick at Arion (the US Jabiru dealer) about the leak and he immediately offered to replace the seal under warranty. I delayed the repair until about 25 hours had accumulated so that if any other early problems popped-up, they could be addressed at the same time - none did! :)
Nick's shop in Shelbyville, Tennessee, is only about an hour's flight west of me, so recently I called to schedule the repair. I was offered the very next day if desired, and scheduled two days later as it was more convenient. I flew-in that a.m. and they immediately set about the seal replacement. Nick said the engine uses an "automotive-type" seal and is a press-fit rather than glued-in with sealant. They do not stretch the seal over the prop flange, rather they remove the prop flange to install the seal. The only catch (which I was advised of in advance) is that the prop flange bolts are secured with Loctite (620, I think?) and it is advisable to give it a 24 hr cure to achieve max strength. I overnighted with my brother, who lives nearby, and the plane was ready to go the following day. A full 24 hrs had elapsed since I had to wait anyway for a morning fog/low ceiling to burn off.
Flew home and after a few hours, so far, the new seal is bone-dry! :)
I noticed recently that Jabiru is now announcing that engines delivered in '24 and later have a 3 yr, 500 hour warranty. I think this is a very generous warranty - sounds like they've probably had a good operating experience now that the earliest Gen 4's have several years of service. Finger's crossed!
So, the point of all this is just give some early experience impressions and give a shout-out to Nick and Jason (the A&P) at Arion for prompt and accommodating customer service! We frequently hear complaints about business that have bad service, but it's infrequent to recognize those providing superior service.
John
N750A
(no affiliation with Arion Aircraft)
Tags:
Thanks for the update and for sharing your experiences.
At similar OAT's, I'm running about 210. I have a rubber duct or collar between the cowl opening ("old style" cowl as supplied by Jabiru USA for the 750 STOL) and the cooler. I did cut an approximately 1" x 4" opening in the top of the rubber duct just as it attaches to the cooler. This allows air to flow over the finned oil sump. I didn't really consider this a mod as it is a very common recommendation.
John
Wish I'd known you were here. I would have dropped by to say hello.
If you're in Tullahoma, you're a wee bit closer to Arion than my brother Bill, who lives in Readyville, east of Murfreesboro. If I ever have to go back for another repair, etc. (hopefully not, fingers crossed!), I'll give you a shout!
John
Hello John, thanks for your post. What fuel are you using on your engine. I had a 2200 on my 701, but had lots of valve problems. I believe it was the 100LL aviation fuel. I should have use additive with the fuel. I am building a 650 and it has a Gen 2 Jabiru 3300. I have never started it. I would like to just buy a new Gen 4 but I need some information. Hauling 91 octane with zero ethanol is a pain. I replace the 2200 on the 701 with a Rotax 912 ULS- flys very well, Very happy
Jerry In New Mexico
N701GJ
Hi Jerry, I use 93 octane mogas/no ethanol. Long ago, I built a fuel trailer with a 12vdc electric pump. I typically buy about 150 gal. from a gas station near me and use "PRI-G" fuel stabilizer. The fueler is kept in my insulated hangar and according to experts, higher octane gas is more stable than lower octane - never had any issues. It keeps the engine and plugs very clean. I only use 100LL when on a long cross-country and can't get mogas. I "think" the Gen 4 is approved for 91 AKI/no ethanol minimum. I use the 93 to be on the safe side and the next lower grade at the station is only 90.
John
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