No - It's not what you may think.
Cont. O-200. I was in this years AirVenture Cup race, my 15th. I have fuel injection, electronic ignition & 9:1 pistons. I normally race at 3,000 RPM. Half way through the 375 nm race, Cyl. #3 suddenly shot up to 455 degrees. I'm going to skip most of the hours and hours of engine troubleshooting (compression checks, borescope, etc.) associated with this condition. Long story short, I completed the race at a lower power setting, then flew from Wausau, WI to OSH, then flew home a couple of days later.
The odd thing is, the cylinder only jumps out of the average range at high power settings, say over 2,900 RPM. Below that, Cyl. #3 falls in line with the other three.
Not finding any obvious problems with the cylinder, I replaced all of my old beat up Westach CHT sensors and installed more robust Insite Avionics gasket type sensors. Test flight yielded no improvement. Here is a photo from that test flight.
Now, here is the crazy thing. I then swapped CHT thermocouples, on cylinders #1 & 3 and made another test flight. If the Cyl. #3 was acting up, on the D-180 display Cyl. #1 should be showing hot, but it was not. It was still showing Cyl. #3. Here is a photo from that flight.
I'm at my wits end, but at this point it surely seems to be an instrumentation problem. Have any of you seen anything like this? What could explain this? Possibly a problem with the D-180?
BTW - I still won my class in the race. But then, I was the only one in the Sprint category.
Thanks
Cont. O-200. I was in this years AirVenture Cup race, my 15th. I have fuel injection, electronic ignition & 9:1 pistons. I normally race at 3,000 RPM. Half way through the 375 nm race, Cyl. #3 suddenly shot up to 455 degrees. I'm going to skip most of the hours and hours of engine troubleshooting (compression checks, borescope, etc.) associated with this condition. Long story short, I completed the race at a lower power setting, then flew from Wausau, WI to OSH, then flew home a couple of days later.
The odd thing is, the cylinder only jumps out of the average range at high power settings, say over 2,900 RPM. Below that, Cyl. #3 falls in line with the other three.
Not finding any obvious problems with the cylinder, I replaced all of my old beat up Westach CHT sensors and installed more robust Insite Avionics gasket type sensors. Test flight yielded no improvement. Here is a photo from that test flight.
Now, here is the crazy thing. I then swapped CHT thermocouples, on cylinders #1 & 3 and made another test flight. If the Cyl. #3 was acting up, on the D-180 display Cyl. #1 should be showing hot, but it was not. It was still showing Cyl. #3. Here is a photo from that flight.
I'm at my wits end, but at this point it surely seems to be an instrumentation problem. Have any of you seen anything like this? What could explain this? Possibly a problem with the D-180?
BTW - I still won my class in the race. But then, I was the only one in the Sprint category.
Thanks