EGT and CHT difference

[MooneyBob]

With the new CGR30 now I can read the temperature differences among the cylinders.

What is the normal EGT and CHT spread? What would be the point I have to take closer look at the engine performance, valves, cylinders, spark plugs, injectors or magneto issues?

Thanks

[kmyfm20s]

These are 2 great webinars on that subject.

http://www.eaavideo.org/video.aspx?v=1316946190001

http://www.eaavideo.org/video.aspx?v=994808107001

[jrwilson]

The jpi manual has the normal spread, I assume the manual for yours has it too, maybe in troubleshooting?

[kmyfm20s]

My last plane with the IO-360 the EGT's ran very close in temp. My current plane with the IO-550 the spread is a little greater. I like how George Braly puts it by saying you really have 4 or 6 independent little engines (cylinders) working in front of you. So my take away has been always knowing what is normal for each of the independent engines to decide if things are going wrong. After I found out what's normal for each one I cruise in normalized mode on the engine monitor to make all things equal and be able to identify changes at a glance.

[Shadrach]

I'm not sure there is a normal and it can change depending on power setting and phase of flight. In terms of raw numbers, In cruise I see about a 30 df CHT spread and around 125df EGT spread

[Marauder]

Here is a typical spread that I see during cruise (disregard the fuel flow, I still hadn't set the correct k factor when this picture was taken):

Typically during the climb, they will be a bit more asymmetrical but usually within 5% to 7% of each other.

Sent from my iPad using Tapatalk

[jrwilson]

From JPI

 

observe for most general aircraft engines.

Parameter Normal range Comments

EGTs in Cruise 1350°F

1550°F

 under 200 HP

 high performance

 EGT should drop 200°F

when full throttle is

applied

EGT span (DIF) 70 to 90°F

120 to 150°F

 fuel injected

 carbureted

TIT 1600°F average  100° higher than EGT

CHTs 350°F (OAT 60°F)

410°F

 normally aspirated

 Turbocharged

CHT span 50 to 70°F 100° with gasket probes

OIL 200°F  oil cooler thermostat

opens at 180°F

Shock cooling* -40°/minute

-55°/minute

-200°/minute

 tightly cowled

 Bonanza

 helicopter

[jrwilson]

So per JPI, CHT span should be 50 to 70 degrees, (100 degrees w/ gasket probes). 

 

EGT should be 70 to 90 degrees.

 

Both assuming fuel injected.