The weather today was great for some flying. Low winds on the ground, puffy clouds around 4,500' and the temps were a little higher than normal. Seems like a winning combination to bang out some hours.
Good news here. My oil temps got up to 180! It looks like my work from yesterday was successful.
it was just perfect outside. It got to be nice and warm in the cabin. I needed to have both the heat on full and a fresh air vent open.
Hmmmm... #2 CHT dropped to 262, then back to 325?
I was running a little on the lean side, but not enough to cause the #2 CHT to be all crazy
My newly installed bathroom in the RV....
This is the nice thing about the GRT engine monitor - the ability for it to show CHT's and EGT's over time. You can clearly see my CHT for #2 is all over the place.
Zoomed in pic of the CHT's and EGT's. What I noticed was as I made the mixture richer, the CHT stabilized. Any time I went under 8.5 GPH at 65%, my #2 CHT freaked out. Notice, however, that the EGT was solid the whole time. I thought at first it was an issue with the probe, but then when I enriched the mixture, the issue went away? Just for the record, the engine ran fine the entire time. never a hiccup.
I leaned it back to 7.5 GPH and the CHT for #2 was just fine. Note also the oil temp was up to 185. Wooo!
3.2 hour flight! 30.2 hours on the airframe! 9.8 left! All great news.
To look further into the #2 CHT issue I decowled the airplane just to see if anything was standing out. I didn't know if an induction leak could give me the results I saw. Right now I am pretty sure it is a CHT probe problem. There is no way the cylinder head could heat and cool that rapidly to cause the results I was seeing, at least without any roughness or hesitation in the engine. Also, the EGT was solid the whole time. If I lost combustion, it would cause a shift in EGT well before CHT.
Another thought is I was playing around with the routing of the CHT sensor wires when I put on my oil cooler blocking plate last night. I could of very well messed with the connection. A new probe runs about $40, so I would rather not waste that if I don't need to. Also, I might swap the CHT sensor to cylinder #4 to see if the problem follows the probe.
Last Modified: August 13, 2023