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Engine data from suspected mag failure...

S

SwimmingDragonfly96

Well Known Member
Continuation of previous post but I'm guessing it's lost in the sauce if I post it in that thread, so my apologies if I'm breaking any rules by creating a new thread. There was a giant spread of CHTs once I richened the mixture when I noticed my EGTs rising. A note, I was running full throttle, 2300 RPM on my recent flight, where as I was slightly lower MAP at 2400 RPM on the older flight.
 

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Need some more info.
Which image is which? What was happening at what time markers?
Could you include the fuel flow (add the optional drop down), if your monitor has that?
 
blaplante said:
Need some more info.
Which image is which? What was happening at what time markers?
Could you include the fuel flow (add the optional drop down), if your monitor has that?
Click to expand...

Hey there,

First image is the flight with the suspected mag failure, right around the 40 minute mark, and they dropped back down around 1:05 mark. Second image is the same flight, with different power settings, two weeks earlier. Same order for fuel flow attached here. Thank you!
 

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Odd that the #3 CHT doesn't seem to follow the pattern of the others. Slight EGT rise, really no CHT drop.
 
I wonder if you leaned too much and just are seeing which cylinders stop firing first. If you stay on the rich side of peak does it fly fine?

Posting fuel flow curves doesn’t help figure anything out at all.

A few weeks ago you posted that your A&p was flying your plane and sending you data in flight. Wasn’t it flying fine for them with regard to ignition?
 
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It looks like the CHT*drops (on three cylinders) before EGT rises, I assume you have not seen any other anomalies for that period of time (OAT, MAP, DA). Perhaps one more image of all graphs but more granular for the time of rise may reveal more.
 
Yes weird on the CHT for sure. The drop in the CHT, on only three cylinders for some reason, is likely due to me richening the mixture to get the EGTs down. I was ROP the whole time and have a carb’d o360.

Plane had no ignition issues just high CHT on takeoff. We retarded the timing two flights ago to help which it did but now this is going on.
 
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