For those of you with engine analyzers that monitor all the EGT/CHT for each cylinder and compare difference evaluate low limits/high limits etc. I guess JPI/Electronics international etc. I have a Electronics International the alarm is on for anything but cruise flight and leaned out. What do you guys set your differences, high/low egt limits etc. I set my CHT at like 400 or so. Any ideas?
Thanks
For those with engine CHT/EGT analyzers?
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jrenwick
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I have an EI UBG-16 with additional sensors for oil temperature and pressure (backup to the original gauges, which are still in the panel, and are considered primary). Since those two gauges are required and have redlines, I set the UBG limits to the redline values. For EGT and CHT, I set the limits a bit beyond any values I normally see in flight, so that I shouldn't see the alarm light unless something happens that I haven't seen before (my CHT high limits are set well below the Continental redline values). If I should get an alarm, and I then decide that there's nothing wrong, I'll adjust the limit accordingly.
The other thing you can do with the EI gauge is use the "Normalized" operation mode. Then it will tell you if there's an unusual excursion on a cylinder.
You can definitely get hung up by these devices. I was flying along one morning, and noticed the engine running slightly rough. The EGTs were low, so I fixated on that for a moment, trying to think what the problem might be. I checked mags, but that didn't reveal anything. Finally I remembered the carb heat, and that solved the problem. If I hadn't had the EI gauge, I'd have noticed the loss of RPM first, and applied carb heat much sooner.
So I've learned that this gauge really is a secondary one, and I need to behave to some extent as if it weren't there. To me, its most important feature is the alarm light, with appropriate limits on oil temp and pressure.
After that, it's nice to know how well the engine is being cooled, and the CHTs are good for that. I lean using the tach, per Cessna's recommendation, and use the EGTs as secondary data.
Best Regards,
John
The other thing you can do with the EI gauge is use the "Normalized" operation mode. Then it will tell you if there's an unusual excursion on a cylinder.
You can definitely get hung up by these devices. I was flying along one morning, and noticed the engine running slightly rough. The EGTs were low, so I fixated on that for a moment, trying to think what the problem might be. I checked mags, but that didn't reveal anything. Finally I remembered the carb heat, and that solved the problem. If I hadn't had the EI gauge, I'd have noticed the loss of RPM first, and applied carb heat much sooner.
So I've learned that this gauge really is a secondary one, and I need to behave to some extent as if it weren't there. To me, its most important feature is the alarm light, with appropriate limits on oil temp and pressure.
After that, it's nice to know how well the engine is being cooled, and the CHTs are good for that. I lean using the tach, per Cessna's recommendation, and use the EGTs as secondary data.
Best Regards,
John
John Renwick
Minneapolis, MN
Former owner, '55 C-170B, N4401B
'42 J-3 Cub, N62088
'50 Swift GC-1B, N2431B, Oshkosh 2009 Outstanding Swift Award, 2016 Best Continuously Maintained Swift
Minneapolis, MN
Former owner, '55 C-170B, N4401B
'42 J-3 Cub, N62088
'50 Swift GC-1B, N2431B, Oshkosh 2009 Outstanding Swift Award, 2016 Best Continuously Maintained Swift
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