Hi all,
I finally finished my panel upgrade to G3XT and started flying (yay!). Unfortunately, I'm seeing very high CHTs after takeoff, especially on cylinder 4 - by the pattern altitude it reaches 450F. It has never done this before. I used to have a 4 cylinder engine monitor from EI (UBG-16) before, and I don't think I've ever seen anything more than 420 or so and even that on very hot days only. I changed all of the sensors during the upgrade, so maybe the old system just didn't show this behavior since it had a significantly slower response.
During the upgrade I didn't change much about the engine, but I removed the primer from cylinder 3 and relocated manifold pressure pickup on cylinder 4. I can't really see how this can change things though.
The engine is O-360 with dual PMAGs. Fuel flow on takeoff hovers around 15-16 gph, which seems ok, but maybe it's a bit low? I'm have the 10-3878 carb, which I don't think was modified.
I checked pmag timing - it seems correct (green lights at the TDC mark). Pmags are running on the A curve.
I found a few gaps in the baffles that I fixed today (haven't flown yet), but I doubt that they can explain ~40 degrees F difference.
Here is the data from the most recent flight - I did a few laps around the pattern: https://apps.savvyaviation.com/flights/4116858/f632a500-a810-4c88-8f84-91810355a125
One weird thing there is that all EGTs go up when I throttle down at the pattern altitude - why would that be? I understand if one cylinder did that due to an induction leak, but all of them? Does it have something to do with the economizer perhaps?
At this point I'm wondering what my options are. The only plan I currently have is to try the lean test (at altitude) to check if my carb is too lean. Other than that I don't really have good ideas.
I finally finished my panel upgrade to G3XT and started flying (yay!). Unfortunately, I'm seeing very high CHTs after takeoff, especially on cylinder 4 - by the pattern altitude it reaches 450F. It has never done this before. I used to have a 4 cylinder engine monitor from EI (UBG-16) before, and I don't think I've ever seen anything more than 420 or so and even that on very hot days only. I changed all of the sensors during the upgrade, so maybe the old system just didn't show this behavior since it had a significantly slower response.
During the upgrade I didn't change much about the engine, but I removed the primer from cylinder 3 and relocated manifold pressure pickup on cylinder 4. I can't really see how this can change things though.
The engine is O-360 with dual PMAGs. Fuel flow on takeoff hovers around 15-16 gph, which seems ok, but maybe it's a bit low? I'm have the 10-3878 carb, which I don't think was modified.
I checked pmag timing - it seems correct (green lights at the TDC mark). Pmags are running on the A curve.
I found a few gaps in the baffles that I fixed today (haven't flown yet), but I doubt that they can explain ~40 degrees F difference.
Here is the data from the most recent flight - I did a few laps around the pattern: https://apps.savvyaviation.com/flights/4116858/f632a500-a810-4c88-8f84-91810355a125
One weird thing there is that all EGTs go up when I throttle down at the pattern altitude - why would that be? I understand if one cylinder did that due to an induction leak, but all of them? Does it have something to do with the economizer perhaps?
At this point I'm wondering what my options are. The only plan I currently have is to try the lean test (at altitude) to check if my carb is too lean. Other than that I don't really have good ideas.