CHT temperature spread

[fabjab]

To all those clever boys out there; please help me find the reason why 2 of my CHT readings read about 30C higher than the others at elevated temperatures (cylinder 2 & 4), but all 6 CHT's read the same when the engine is cold.

I would expect the bank with 2,4 and 6 to be slightly hotter than the other side due to the prop rotation, but not this much?

Thanx,

Carl.

 

[Youngmic]

G'day Mate,

Try heating some engine oil up to say 120 degrees or just below the boil temperature for oil and drop the CHT probes in. You should see the same temp on all.

A 30c split may not be that unusual on a homebuilt. You might have a bit of work to do on your baffles to correct this split.

Regards
Mick

 

[fabjab]

Maybe a picture can illustrate what I am talking about a bit better.

The plot depicts CHT's while doing 3 circuits.

I have also checked the temp on one of those CHT's with a conventional CHT display and different probe, and then the temp was in line with the other CHT's.

Always the same 2 a bit hotter than the rest and only at elevated temp's.

 

[marty]

I am having the identical problem (on my jab 3300 engine) except  that I have three CHTs showing 30-40 plus higher at elevated temps. They are not on the same bank.
My factory built Jab430 seems to fly OK and there does not appear to be any difference in the setup -cowling - ducting to a similar aircraft, the temperatures of which are normal.