Oil analysis question

[tshort]

Curious what you all would do to troubleshoot the following.
I sent a sample (report attached) when I took the airplane down for annual last week.

Overall it has been running fine; on one flight late last year there was just a hint of rough running on a night takeoff, barely noticeable but just a hint of roughness. I flew for 90 minutes or so before the annual / oil sample and it ran fine.

We are planning to borescope the cylinders during the inspection.

Thanks in advance.

N3949V-250130.pdf

[johneeb]

Tom, while you are Borescoping your cylinders also look to see if a piston pin end plug has been scuffing the cylinder wall.

[tshort]

The borescope images were not super conclusive; #4 appeared to have a slightly different pattern on the cylinder wall but nothing that looked like a pin scuffing or anything else.
I will see if I can post images later.

Our current plan is to fly it 5 or so hours and send another sample.

Any other thoughts?

[bjan11]

Is five hours enough to get a good signal in the next analysis? I'd probably shoot for ten.

[tshort]

Good point; that is what my A&P wanted to do.
He is a reasonable guy so I will d/w him.

Thanks

[GAHorn]

I’m curious why the lab thinks “break-in” occurred in 2021. Has there been a cylinder change?

Have you made a change in oil type/brand during this history? Do you use any additives? (noticing calcium, magnesium, phosphorus)