Good compressions, but still blowing oil out the breather tube. What to do?

[A64Pilot]

On 2/15/2023 at 7:46 AM, RoundTwo said:

I got to the end of the thread and am disappointed to not be told what @Oldguy found to be the cause.  I know it was almost 4 years ago but I’d like to hear the conclusion.

Very likely it’s still flying around, a qt every 5 or 6 hours is in my opinion entirely normal, especially if the level is kept any above 6. Oil level above 6 on mine I may as well smear on the belly, because in less than an hour that’s where it’s going to be. I think mine is average

[jetdriven]

We just had a client fear that we take care of his airplane, and it was pouring smoke and combustion Byproducts  out of the breather tube so bad it looked like an airshow plane while he was taxiing in from a local flight. 
Compression tester number four was weird it would either show 30 or 79, and jiggling the prop a little bit could make it jump back-and-forth. We soaked  it overnight in B12 and it got a little better but it was still doing it, so we pulled the cylinder and found this.  

[Oldguy]

On 2/15/2023 at 7:46 AM, RoundTwo said:

I got to the end of the thread and am disappointed to not be told what @Oldguy found to be the cause.  I know it was almost 4 years ago but I’d like to hear the conclusion.

And from there, the story got a bit convoluted...

I continued to fly it using a some oil from time to time with no real problem. Then, in early 2020, it went into the avionics shop for some upgrades. Between COVID running rampant thru the shop employees, problems with manufacturing delays for the hardware due to COVID, poor workmanship by the contract avionics techs brought in due to COVID, (catch the running theme here?) it was in their shop and down for over a year! It seemed every time it was pronounced finished, it went back within a week. Actually had to get a ferry permit to get it home for the annual the last time.

That's when we found the two rusted/pitted cylinders which apparently resulted from sitting in the avionics shop for so long.

Ordered two cylinders and in the months while waiting for them had the exhaust rebuilt by Acorn in Canada (HIGHEST recommendation possible for those folks!) and finished the interior refresh. Finished the break-in on the engine by flying it home to Lakeland, FL, where we retired at the end of 2021. Since then, it has found a new home and pilot via Jimmy Garrison and now resides in northern Vermont. 

So the saga of N5767Z continues with a refreshed top-end for two cylinders. She was running very well with no oil blowby (the oil rings on one of the cylinders replaced had lost tension) and making good power.

[RoundTwo]

8 hours ago, Oldguy said:

And from there, the story got a bit convoluted...

I continued to fly it using a some oil from time to time with no real problem. Then, in early 2020, it went into the avionics shop for some upgrades. Between COVID running rampant thru the shop employees, problems with manufacturing delays for the hardware due to COVID, poor workmanship by the contract avionics techs brought in due to COVID, (catch the running theme here?) it was in their shop and down for over a year! It seemed every time it was pronounced finished, it went back within a week. Actually had to get a ferry permit to get it home for the annual the last time.

That's when we found the two rusted/pitted cylinders which apparently resulted from sitting in the avionics shop for so long.

Ordered two cylinders and in the months while waiting for them had the exhaust rebuilt by Acorn in Canada (HIGHEST recommendation possible for those folks!) and finished the interior refresh. Finished the break-in on the engine by flying it home to Lakeland, FL, where we retired at the end of 2021. Since then, it has found a new home and pilot via Jimmy Garrison and now resides in northern Vermont. 

So the saga of N5767Z continues with a refreshed top-end for two cylinders. She was running very well with no oil blowby (the oil rings on one of the cylinders replaced had lost tension) and making good power.

I just heard Paul Harvey in my head. 

[Will.iam]

On 2/18/2023 at 2:13 PM, jetdriven said:

We just had a client fear that we take care of his airplane, and it was pouring smoke and combustion Byproducts  out of the breather tube so bad it looked like an airshow plane while he was taxiing in from a local flight. 
Compression tester number four was weird it would either show 30 or 79, and jiggling the prop a little bit could make it jump back-and-forth. We soaked  it overnight in B12 and it got a little better but it was still doing it, so we pulled the cylinder and found this.  

So is that top ring stuck in the groove?