One colder EGT

I was graphing my engine data coming back from Osh and I noticed that I have one EGT (#1) that is 100 degrees cooler than the other 3. The cylinder temps were within 10 degrees of each other and the other 3 EGT's were within 25 degrees. This was during cruise flight at just over 2500rpm. Interestingly, at lower RPM's it seems more in line with the others. Any thoughts on why one EGT would be cooler than the rest?

(I may go do some flight tests at different RPM's to see where it splits off from the rest...)

Probe problem

Could be the probe or wiring to the probe. If it was something systematic with the cylinder such as mixture or spark problems, you will most likely see a change in cylinder head temp as well.

Mathew, the EGTs are VERY sensitive to the distance from the exhaust valve. The absolute number is almost meaningless, the amount it changes when you lean is what matters as I understand it.

If it will cheer you up take a look at some of my traces. Click on my blog below.

Depends,

What was the difference say 3 months ago or even on your way to OSH.

Then consider
Plugged injectors.
Worn or defective injectors.
Leaks in the fuel lines and flow divider.
Misadjusted or defective fuel controller.
Misadjusted or defective carburetor.
Fuel distribution problems.
Intake leak.
Defective fuel pump.
Leaks in upper deck lines.
Intake or exhaust restriction.


A good resource for using your egts to trouble shoot is here...

http://www.buy-ei.com/Information/Pilots%20Manual.pdf

exhaust temps

Check for cracks in the exhaust that is cooler. This was my exact indication and I found a crack 3/4 of the way around the cooler exhaust pipe just adjacent to the EGT probe clamp. Normally my EGT differ by <30 degrees.

Steve
RV7A Flying

Steve Sampson said:

The absolute number is almost meaningless........

Click to expand...

I agree. Your temps are actually very close and very good.