Yesterday I took my RV-7A up for a flight after my conditional inspection. I have been flying my RV for over 10 years with only 500 hours on my bird. I know that is a bit embarrassing.
20 miles after departing the airport (KTUS) I noticed my number #3 EGT was displaying about 200 F degrees lower than normal. #3 CHT was normal. The engine was running smooth. I am flying with a Dynon Skyview and previously years with a Dynon D180 so I have always had full engine monitoring.
The EGT failure behavior I have seen in the past is rapid changes in the display, extremely temperature (2000+F) or total failure (X’d out on the display). Since #3 EGT was displaying at least 200F lower than normal and the rest of the EGT’s I was thinking maybe I had a fouled plug, magneto issue or just another EGT failure.
Out of caution I returned to the airport and upon landing the #3 EGT X’d out on the display. Now I had a better feeling the EGT failed. I did a run-up and mag check on the ground and the #3 EGT didn’t respond. Also verified it wasn't a spade lug connection or other wiring issue. So once again I am replacing another EGT.
My question for those more experienced then me is:
If I did have a one bad spark plug in a cylinder, would the EGT in that cylinder be lower than normal during cruise flight? Would CHT run cooler also? My thought considering the decrease in the burn efficiency in that cylinder the EGT might be cooler.
I have replaced at least 2 other EGT’s over past 10 years. One was a real pain because the tip of the probe swelled up and I had a very difficult time getting the tip of the probe out to the hole in the exhaust tube. Hopefully this one will be a bit easier.
Thoughts?
20 miles after departing the airport (KTUS) I noticed my number #3 EGT was displaying about 200 F degrees lower than normal. #3 CHT was normal. The engine was running smooth. I am flying with a Dynon Skyview and previously years with a Dynon D180 so I have always had full engine monitoring.
The EGT failure behavior I have seen in the past is rapid changes in the display, extremely temperature (2000+F) or total failure (X’d out on the display). Since #3 EGT was displaying at least 200F lower than normal and the rest of the EGT’s I was thinking maybe I had a fouled plug, magneto issue or just another EGT failure.
Out of caution I returned to the airport and upon landing the #3 EGT X’d out on the display. Now I had a better feeling the EGT failed. I did a run-up and mag check on the ground and the #3 EGT didn’t respond. Also verified it wasn't a spade lug connection or other wiring issue. So once again I am replacing another EGT.
My question for those more experienced then me is:
If I did have a one bad spark plug in a cylinder, would the EGT in that cylinder be lower than normal during cruise flight? Would CHT run cooler also? My thought considering the decrease in the burn efficiency in that cylinder the EGT might be cooler.
I have replaced at least 2 other EGT’s over past 10 years. One was a real pain because the tip of the probe swelled up and I had a very difficult time getting the tip of the probe out to the hole in the exhaust tube. Hopefully this one will be a bit easier.
Thoughts?