Hottest cylinder CHT at cruise

[DeeDub]

Just for the discussion, for the hot J operator. How many hours are on that engine?  Given good operating techniques, my experience has taught me that CHT temps increase as the chronological age of the engine or TBO life span decreases.  Any chance that this engine is getting near TBO?  You can chase a lot of ghosts, but in the end, just throwing more money in the pit when the simplest explanation might be the most practical.  On my third IO 360 A1A in 40 years.  Never seen those CHTS!

[0TreeLemur]

On 7/3/2022 at 8:48 PM, A64Pilot said:

It’s my belief that cyl head temp tracks power output more than anything else

I think CHT is typically a good proxy for power output for a cylinder, but it is a better proxy for cylinder pressure.   A cylinder that is experiencing pre-ignition has a really high CHT, but is not putting out much power.  It does have a very high cylinder pressure.

For an appropriately timed engine that is operating normally, I agree with you.  But, it isn't an absolute indicator that you can use to compare cylinders because of differences in cooling air flow/etc.   The CHT in #2 in my IO-360s is always about 25F cooler than the rest in cruise.  But when I lean it out LOP it is neither the first nor the last to reach peak EGT.  So, it's in the middle of the pack in terms of fuel flow.  If one flight it is significantly different from about 25F different from the other cylinders, I'll suspect something might be wrong.

[Echo]

On 9/20/2022 at 3:09 PM, Shadrach said:

It's a shame Lycoming did not specify a range. If 20° and 25° are approved, anything in between is acceptable.  My A&P busies himself with other things until I have finished timing a mag. He thinks I am overly fastidious. I am happy to take a little extra time to ensure I have set the maximum advance that can be read as 25°. 

 

I am going to have a great day.  Not even through a cup of coffee and I have a wonderful four syllable word in that made me laugh out loud.  Ross, My mechanic is someone I consider as a friend.  I bet yours is too.