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Recent increase in EGT of right engine after annual

Recently the EGT have increased across all six cylinders to about 1430-1460 degrees when trying to fly LOP!! I ve flown this engine since 2007 with out EGT issues. CHT are fine 300-330 degrees.First what could have changed?? We checked the timing at 20 degrees . Also some say don t worry about EGT if CHT;s are good ! Help and thanks

Model: Baron 95-B55
Aircraft Serial Number: TC 2076
Posted 11/13/2023 - 3 months ago
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I agree. Something has changed!!! So let me ask a few questions:

1. How do you go from ROP to LOP? Do you use a lean find. Or do you use the "big Pull" and know you are LOP when the airplane slows down?

1a. Which engines does your Baron have?

2. Has your fuel flow changed on the engine with the higher EGT, compared to the pre-annual situation?

3. You implied that your CHTs are still the same as before the annual. Has the fuel flow changed compared to the pre annual readings?

More questions to follow your answers.

Tom

Posted 11/14/2023 - 3 months ago
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I'm not sure I can agree or disagree; how about a little more information?

What used to be the fuel flow and EGT's, compared to now at same MAP and RPM?

Mike
ABS Technical Advisor

Posted 11/14/2023 - 3 months ago
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Tom and Mike thanks for getting back. I ve been away a day or two. I dont have all the answers but here goes. 1. Ive been flying LOP us the six probe JPI for about 15 years, I reduce Mixture fairly smartly but don t like the Big Pull. I watch as each cyl column inverts and try to fly about 20 degrees LOP. Not happening on the older rt engine. Either runs rough or the EGT s are high.. 3. I do not have GAMI injectors on either engine but were otherwise balanced pretty well in the past. #. I have IO 470L engines.
I will get back to you with fuel flows and Temps at different power settings..Also recall a recent Mike Bush article basically ignoring EGT and lives by CHT only!! Hard for me though ,.thanks again rick

Posted 11/16/2023 - 3 months ago
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Rick;

It is common knowledge that CHTs will follow the EGT; the EGT is quicker to respond and can give a pre-cursor to the CHT. If after leaning, the EGTs are higher, but you didn't say how much higher, and the CHTs are what you are used to seeing, this may be an instrumentation problem. Don't know yet. While you are gathering more data, also take note of anything else that has changed, even something small like there is now a knob split on any of the three primary controls that was not there before.

Mike
ABS Technical Advisor

Posted 11/16/2023 - 3 months ago
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Ok I will do and dial in the fuel flows and temps when next I fly. also wilL have a detailed History info..During the Sept Annual the mag timing was off by 2 degrees and returned to 20 degrees per Book. I had timing reset again and reduced slightlY to just below 20 degrees and the EGT stayeD the same or got worse. So does Mag timing have much to do with EGT? thanks

Posted 11/16/2023 - 3 months ago
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Mag timing will affect EGT. If you are running slightly below 20° timing, that can make a difference, and not change the CHT for the worse. But again, I don't know what the delta is between the old EGT and new.

Mag timing is 'a thing' on the higher horsepower engines, like the TSIO520WB, where CHT can be an issue. We shoot for 19.5° - 19.7°.

Mike
ABS Technical Advisor

Posted 11/16/2023 - 3 months ago
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Guys I m going to fly again probably today. 1. confirm EGT and CHT at 65% power 2. Compare to prior numbers from a couple of months ago..Delta! 3. Record fuel flows at those power settings. Also compare left to problamatic right engine.Would this satisfactory?

Posted 11/17/2023 - 3 months ago
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As much information as you can overload us with, the better!

Mike
ABS Technical Advisor

Posted 11/17/2023 - 3 months ago
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Gentlemen here are the latest on my Rt engine EGT's . First I confirmed that all Cyl EGT s were below 1400 degrees prior to the annual. Highest was #1 at 1380 or higher LOP .So now unable to keep EGT below 1400 and at LOP ranges between 1460 and 1490 EGT.
The fuel flow at 65% and 5500 feet is approx 11.8 gph with the very hot EGT.
Next I increase fuel flow on the right engine to achieve below 1400 degree EGT that took approx 15.8 gph.. Way more than before.
So would the 2 degree change to the Rt Eng mags have made this difference? I need to find out was it increased by two or decreased? Any other thoughts?thanks

Posted 11/19/2023 - 3 months ago
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Rick;

It may be an internal timing issue with one or both of the mags on that engine. If a mag requires retiming between 500-hr inspections, one should consider if the internal timing has slipped, either through bearing wear or point wear, and not just arbitrarily retime the setting to the engine. (Not uncommon to need to retime at 50-100 hours due to parts seating, but after that, there is wear affecting the timing.) If the internal timing slipped, the mag is operating at less than optimal efficiency. What mags do you have?

Did you happen to perform a LOP mag check? If you have a lazy mag, that would easily be spotted with that check, and incomplete combustion can raise the EGT without an apparent rise in CHT.

Mike
ABS Technical Advisor

Posted 11/19/2023 - 3 months ago
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Recent increase in EGT of right engine after annual