Anyway, I had to warm up the oil, so I went flying with my hangar neighbor Mark (Comanche and Archer owner). He had never flown in an RV before. He seemed pretty impressed with the lack of takeoff roll, the responsiveness, and the acceleration. We did a bunch of rolls and steep turns and all sorts of stuff. Good time, and the oil was plenty warm by the time we got back.
The past couple of times I've had the bottom cowl off, I noticed some slight spattering of oil on the right side, so I wanted to see if I could find the source. The engine has been mostly bone dry, and I couldn't really tell where it was coming from. It was somewhere in this right rear corner.
I noticed some oil on the bottom of cylinder #3's fins, but I couldn't really tell where it had come from. I did notice some oil on the threads of the oil return line fitting.
And then my heart almost stopped...I found a crack in cylinder #3. It looked like oil might be coming out of the crack.
If you recall from building the baffles, on the angle valve cylinders, the baffles attach in a few spots via AN3 bolts going into cylindrical nuts that slide up into bosses on the cylinders. Jeez, had I over-tightened this one accidentally or something? I was pretty pissed for a bit, thinking I might have to replace a cylinder. Dammit!
Well, I disconnected all sorts of junk...fuel return line, oil filler tube, lower baffle retainer wires, right ignition coil, baffle seals, manifold pressure hose, heat SCAT tubing, etc. It was a significant ordeal getting the right rear baffle off -- not that difficult, just a lot of doodads to remove to get it out. Once it was all disassembled, I cleaned the area and took a closer look at the crack. Even though I could get my fingernail under the top of it...
...it quickly occurred to me that this was just a blemish in the engine enamel. And to top it off, I now remembered having seen this on the engine when I first installed it. I remember thinking that it looked like a paint booger, but I didn't want to mess with it and spoil the appearance. Whatever!
Anyway, just to make sure this wasn't a crack in disguise, I chipped the paint booger off. Yep, no crack. Just a friggin' paint booger. PHEW!
Long story short, I put everything back, and I reseated the oil line 45 fitting with fresh pipe thread sealant. I also installed a longer AN3 bolt and put a large area AN970 washer under the bolt head and lock washer. I could see on the baffle material that eventually it would probably crack here. This is yet another one of those areas where Van's baffle kit doesn't tell you to reinforce, but you really, really need to!
After a while I got everything back together, topped off the oil, ran it up to check for leaks (none found), and put the cowl back on.
Thank frickin' goodness this wasn't more of a problem than it was. I'm glad I have a critical eye for this stuff, but it can be frightening sometimes. I'd rather spot trouble than ignore it, though.
Tomorrow is the big Chino RV Fly-In and Planes of Fame Airshow. Can't wait. I think we're gonna have a huge RV turnout. Fortunately my plane will be on the flight line this year (and not in the hangar with a cylinder removed!).