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High Right EGT and Cylinder Head Temps

  • hockeystud87
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2 weeks 4 days ago - 2 weeks 4 days ago #21707 by hockeystud87
High Right EGT and Cylinder Head Temps was created by hockeystud87
Hello I have a weird scenario with my plane. I seem to have gauges that all read high temps on the right side of my engine. I have the old cylinders that give cylinder head temps not coolant temperatures. EGT's are reading the back two cylinders. I have synced the carbs and my prop is pitched about as close as I think I can get it.

Gaunge readings
Rotax 912 UL 1992 (stock)
5100 RPM cruise
5200 RPM (climb out 65mph)
90mph ish cruise
Back Right Cylinder 206 F
Front Left Cylinder 178 F
Back Right EGT 1550 F
Back Left EGT 1460 F
Oil in 200 F
Oil out 235 F
All #'s are at 5100 rpm Cruise

So I understand the front cylinder and back cylinder head temps being different. I assume that is due to the air temp difference from front and back. The EGT is a little different. What I did discover is that the EGT probes are in slightly different spots.

EGT location on the back left seems to be .25"-.5" further away from the exhaust port of the cylinder. Plus it's on a slight bend where the other side seems to be on a flat and in direct line of the exhaust. I have included pictures of the two sides. The one on the bend is the LEFT side lower temp reading EGT. The total distance from the cylinder head, not the flange, is 2in. This seems close over all.

Are my engine temps reading different just due to the right side probe being slightly closer and in direct line of the exhaust? My grandfather noted this same issue many years ago so it's been a persistent situation.

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Last edit: 2 weeks 4 days ago by hockeystud87.

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1 week 6 days ago #21768 by Wang Shu
Replied by Wang Shu on topic High Right EGT and Cylinder Head Temps
Difference of EGT less than 100 centigrade is acceptable at low rpm. But at 5000 rpm diff. Is 50 +- c.
Causes. Check carburetor lean mixture.
On ground test, measure EGT directly by flydat.
CHT. Higher. May be due to improper uses of coolant.
Pic shows. Worn-out EGT prob/wire.

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1 week 4 days ago #21780 by garrett
Replied by garrett on topic High Right EGT and Cylinder Head Temps
You could swap the CHT probes and see if its a difference in temp probes. Exhaust gas temps drop about 100 deg per inch, also EGT probes have a life usually about 300 to 600 hours. What do the probes read when the engine is cold, do the EGT's And CHT's all read the same?

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1 week 3 days ago #21786 by Wang Shu
Replied by Wang Shu on topic High Right EGT and Cylinder Head Temps
EGT probs life 300_600 hrs.
Can you tell life in years? Or replace when faulty declared?

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1 week 3 days ago #21791 by garrett
Replied by garrett on topic High Right EGT and Cylinder Head Temps
You can usually see it when they start to fail and I replace all as a matched set. I you have more than one the rest probably are not far behind failure/accuracy wise.

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1 week 3 days ago #21792 by Roger Lee
Replied by Roger Lee on topic High Right EGT and Cylinder Head Temps
Just replace them when they start to go bad. They only cost around $30-$40 and easy to replace. (most of the time :))
Some go way beyond 300-600 hours. I have some on planes that go to TBO without any issues. It's just the luck of the draw.

Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-574-1080 Home (TRY HOME FIRST)
520-349-7056 Cell

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1 week 3 days ago #21793 by kenryan
Replied by kenryan on topic High Right EGT and Cylinder Head Temps

Roger Lee wrote: They only cost around $30-$40 and easy to replace. (most of the time :))


Unless you have the 914 in which case EGT sensor Rotax 966-370 is $243.74 EACH!

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5 days 4 hours ago - 5 days 4 hours ago #21852 by N874CB
Replied by N874CB on topic High Right EGT and Cylinder Head Temps
This is what I use on my 914 with the Grand Rapids box, $49. The Rotax part may be that much but other folks make them and would be much cheaper.

www.aircraftspruce.com/catalog/inpages/grtegt-hcs-01.php
Last edit: 5 days 4 hours ago by N874CB.

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5 days 4 hours ago #21854 by Roger Lee
Replied by Roger Lee on topic High Right EGT and Cylinder Head Temps
This is one of the most common types out there and easy to install.

Roger Lee
LSRM-A & Rotax Instructor & Rotax IRC
Tucson, AZ Ryan Airfield (KRYN)
520-574-1080 Home (TRY HOME FIRST)
520-349-7056 Cell

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