I’ve had an oil consumption issue in my 2015 CC340 engine (engine built/assembled in 2014 by Aero Sport) for some time now and just recently found out what the issue is but I’m trying to figure out WHY at 750hrs on the engine! First, just a bit of background on my engine; I’ve never had a heat problem with my CHTs or EGTs nor have I ever had the need to fly CHT’s above 400 degrees. A typical flight in cruise for me at 2200-2450 rpms has my CHT’s between 350-375, EGTs 1300-1350, oil 180-190. I have the standard 25-degree timing ring and normally cruise 50-100 degrees ROP. I just recently did a hot leak down test before my Idaho trip and it was good (74/80, 76/80, 80/80 and 79/80).

Now the problems: The engine started out pretty normal after break-in and then at about 300 hrs I started noticing the oil consumption going up from 1qt per 10-12hrs to 1qt every 6-8hrs and then to 1 qt every 4-6 hrs in the first quarter of 2019. During this time frame the oil reports continued to show slight increases of lead, which I didn't think much of at the time. I also noticed that the residue on the landing gear started tuning a dark brown rather than the light grey it had been. This continued to get darker until a compression ring broke on my way back from Utah in May 2019. After getting that problem fixed I thought the oil consumption would go back to 10-12/qt rate but it didn’t, It continued at to get worse and just recently during a trip to Idaho I was burning 1 qt every 3 hours with 750hrs on the engine.

The bore-scope on cylinders 1,2 and 4 showed a considerable amount of oil was getting thru the rings, #3 which I rebuilt 1 year ago was good. After removing a the jugs it was very apparent the rings were completely worn out on 1,2 and 4, this had obviously been going on for some time. Aero Sport now has all the jugs and they are also baffled why the rings failed so soon. Possibly the wrong rings for these kind of cylinders or a bad batch of rings (whatever that means?????). The other issue I’m having is pitting on the valves and pistons. 3 exhaust and 3 intake valves need to be replaced, however, all the valve guides and cylinder walls are good. I fly about 150hr a year and have never pulled any water out of the tanks so corrosion seems unlikely and this kind of pitting was not due to detonation. Again baffling.

My question to everyone is: has anyone else had this kind of ring wear/problems this early in the life of their engine, especially ones built on the 2014-15 time frame? This was also the time frame in which Continental was purchasing ECI Titan.

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