This UL is starting to make me lose "the love" just a bit.  20 hours on the rebuild and postflight inspection discovered this!  (Sigh) - gonna pull the prop flange bolt and see if the oil stop on the end of the crankshaft is leaking.

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Yep, I think my patience would be wearing a little thin at this point!

Pretty sure you mean “how badly” the seal is leaking.....  wow.  I hope they can resolve this quickly for you.

So, pulled the prop flange and found what appears to be uneven contact betwen the faces of the flange and crankshaft end.  There is a bit of wobble and uneveness between the two.  The flange is new, the crankshaft original.  What appears to be a leak is most likely a mix of rust, fretted material from the flange, flange locking plate and grease which is used on the flange bolt.  Too dark to be fresh oil, sludgelike versus thin viscosity like fresh synthetic oil.  The front seal is not weeping at all, the oil stop inside the crank shaft is good - no evident of oil getting by.  I sent a clip of the "play" between the flange and crank to UL along with a few pics.  I'll see what they think.

I’m not sure that’s good news.....   will keep fingers crossed for you.

Hope UL can take care of you...

Now that the prop is off, did you by any chance check the prop tips for tracking? I am thinking wrapping of flange or misalignment during machining. The word “play” indicates something movable, hope that is not the case.


Very disappointing!  Hope UL can help you out with troubleshooting this. Have you put a dial indicator on crankshaft.

That stinks.. I think I would be looking for a new engine. I love the hp love the light weight but wow

Not a direct UL issue, more of a heads-up. I just finished a fairly extensive plane rebuild including having engine examined for prop strike damage. One of the items replaced was the landing gear. Based on my experience this morning, make certain that the cotter pin locking the castle nut holding your tire on to your axle is damage to my plane involved in my interesting landing, just need to replace a bearing and nut. Could have been painful. 

Good news, no oil leaks. The new o rings I just replaced for the push rod tubes seem to be doing their job.



I was reminded of your description of the prop flange/crank end wobble when I came across this video.  Relates what happens when the wobble gets excessive.....

Yes, familiar with roll coupling and torque issues involving items that rotate.  Intersting video though! Here's a pic of what happened in my case with a two bladed loaner prop and flange after 3.9 hrs of run time.  Discovered this upon postflight after picking up resonant vibrations in flight while in certain RPM ranges.  Smooth initially, but things changed notably while in flight.  Brought it back home and found these broken AN5 clamp bolts!


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