Did some maintenance today, pulled and cleaned all the plugs and reinstalled them in the same cylinders, but swapped bottoms and tops. I also did an automotive compression test (cold, I ran out of time to do it hot as well - 122, 120, 125, 123). After that I buttoned it all up and went flying for about an hour to top off the tanks for this upcoming weekend and to warm the oil before I changed it.
Some spark plug images:
#2 bottom
#4 top
#1 bottom
#3 bottom
I tried to look at the valves but I couldn't get a good angle through the spark plug holes with the non-articulating head on my boroscope. I might try to borrow one from work one of these days just to see how they look.
Just for completeness I pulled the viscosity valve plug and ran a magnet down there - returned nothing. I did this before the flight, and didn't think to look in there after the oil had all been drained. I had also meant to pull the oil filter adapter on this oil change and see if there was anything funky going on with the gasket, but I forgot to order a new one and couldn't get to that.
But I did try to use my boroscope to look in the oil filter adapter while I changed the filter and came up with these:
Vernatherm! This is from the left-most hole in the area the filter covers as viewed from the back of the engine.
The thing on the left appears to be the pressure relief valve. Second pic is the same area, just moved to a slightly better angle to see the thing. Also, should any of this be . This is from inside the part that the filter actually screws into.
I think this is the face of the pressure relief valve. This is from the right-most hole in the area the filter covers as viewed from the back of the engine.
Anyways, I changed the oil and took a sample that'll go out to Blackstone Labs tomorrow morning. Then I added some MMO to the fuel and buttoned it all up for the night.
Some data points from my oil warm-up flight:
Segment 1:
2,400 ft (30.05)
139 mph IAS
70 deg F OAT
2475 RPM
CHTs: 320, 333, 345, 338
EGTs: 1305, 1334, 1301, 1364
OT: 200 deg F
Delta P: 4.1
Segment 2:
1,800 ft (30.05)
138 mph IAS
73 deg F OAT
2400 RPM
CHTs: 326, 341, 354, 345
EGTs: 1313, 1346, 1310, 1368
OT: 210 deg F
Delta P: 4.1
I did notice that my EGTs on #2 and #4 were oscillating up and down about 5-8 degrees. I don't usually watch them, so I don't know if this is normal. It ran the same as it always has - very well except higher oil temps that I would expect.