CHTs 231K

[PEDRO]

The number 6 cylinder in my 20k is running 54 degrees higher than number 5 cylinder. I was wondering if any one else was experiencing  That problem? 

[PeteMc]

Interesting.   My #5 is running hotter and my mechanic says that's not unusual and we'll tweak the baffling a bit.  He also said #5 was a big issue with the Ovations.  (I think he said it was the Ovations.)  

[ArtVandelay]

Interesting.   My #5 is running hotter and my mechanic says that's not unusual and we'll tweak the baffling a bit.  He also said #5 was a big issue with the Ovations.  (I think he said it was the Ovations.)  

Was that because of oil cooler robbing cooling air from the cylinder?

[jlunseth]

5 & 6 are right at the intake holes, as opposed to 1 & 2, which sit behind all the other cylinders. One of 5 & 6 is partially blocked and the other is not. I don't remember without looking what is there doing the blocking, I think it is the intake scoop for the induction system, but not sure. It would be nice if the CHTs were all within a few degrees of each other but that is generally not the case. My 6, sitting right in the unblocked intake hole, is generally cooler than the others. Rather than comparing 5 to 6, I am more interested in the variation across all six. If your 5 is the hottest and your six is the coolest, and all the others are in between, that is not a bad spread based on what I see on my engine and tweaking the baffling might help. The other contributor to temp differentials is how evenly the fuel flow is between the cylinders, if you run ROP and have one that is persistently significantly leaner, that could be your warmer cylinder. The usual cure for that is GAMIs if you don't already have them. But I think you are chasing a spread that is pretty normal given the layout and untuned induction system of the engine and compartment. Now that I said that, someone will have a TSIO360 where all the cylinders are running within a few degrees of each other.

[whiskytango]

+1 on Cylinder No. 5 running about 50 degrees hotter than all other cylinders.  I have to trail cowl flaps 1/2 open to keep No. 5 at the magic 380 F CHT.  I've had my IA look at it on every annual, and he says he can't see any problems with baffling.  The problem stays at No.5 if the thermocouple leads are switched so it is a real thing.

[PeteMc]

The partial block is the cowl...  Other cylinders get air that comes in and down through the fins.  5 & 6 only get it  across the top and some down just do to the volume trying to get through.  Don't exactly remember why 5 tends to run hotter.  I want to say it's the up cycle of the prop, but don't remember if that is correct or not.  

A&P or someone in the know what to refresh me on why Cyl 5 tends to run hot?

[Guest]

12 hours ago, PEDRO said:

The number 6 cylinder in my 20k is running 54 degrees higher than number 5 cylinder. I was wondering if any one else was experiencing  That problem? 

First thing is accuracy of the information, what type of engine monitor and more importantly what type of thermocouples?  

The quality of your baffle sealing tapes and the quality of your metal baffles and how well they are sealed to the engine block etc are critical to proper cooling.

Clarence

[hubcap]

#5 is my hottest cylinder and #6 is my coolest cylinder. I believe this to be normal in the 231. 

This is according to the JPI 900.

Edited July 17, 2021 by hubcap

[Pritch]

From a flight a couple of months ago.  #5 is the hottest and #3 is the stock probe. #6 is a new cylinder and is the coldest.

Pritch

[Guest]

Cylinder #5 is the location of the OEM CHT probe, unless you have a certified replacement indicator, the accuracy of your EDM 7-800 series indicator will be in question.

Clarence

[carusoam]

As always…

Know where the ships gauge is mounted…

And know if the JPI sensor for that Cylinder is riding piggy back on something…

The number your are reading might very well be related to the type of sensor and where it is taking its reading from…

My #5 is also the warm one on the IO550… the airflow in the region is affected by the alternator mounted in front of it…

Baffling is an important part of the discussion… many Baffles weren’t perfect on day one…. Many have been improved since then… 

Go MS!

-a-

[81X]

My #1 and 2 cylinders run hottest on my K 231 LB model with the airflow intercooler and GAMIs.  
 

The GAMIs really helped balance the heat load a bit.  

[chrisk]

On 7/23/2021 at 6:06 AM, 81X said:

My #1 and 2 cylinders run hottest on my K 231 LB model with the airflow intercooler and GAMIs.  
 

The GAMIs really helped balance the heat load a bit.  

Same here, except I don't have GAMIs (which I have plans for)