912 CHT - which one?

[HansLab]

Hi all,

There is a CHT probe on the #4 cylinder, and on the #2 cylinder.
Which one to pick? I guess the 4 is the hotest, but I wonder why the #2 probe is mounted anyway?

[DBVZ]

2 and 4 are both on the left side, so perhaps to get a front and back temp? You have max limits, but also minimum for TO power, right?

Since they are both on the same carb, I would have thought perhaps something on the other side would be needed too. I have all 4 on my Jabiru, and appreciate knowing where they are all running.

[HansLab]

..and put them on different gauges, that is? (of course I guess - but I'd ask anyway..)

[DBVZ]

If you are asking me, mine all go to the EFIS and are individually displayed along with a couple EGT's.

[Dave S]

Hi Hans,

I believe the theory for a single CHT probe on a multicylinder engine is to put it on whichever cylinder is the hottest. I think you have it right.

Sincerely,

Dave S
KF7 Trigear
912ULS (with CHT probe on starboard rear cylinder)

[HighWing]

For someone who has always run with only one sender - the hot one, is there something I might have missed not having another or all four. I always found that in my installation, the engine usually ran on the cool side, to the point that I installed radiator flaps to warm it up a bit. This time I am going to a coolant temp probe only I guess the question is, what are the risks having only one in a liquid cooled engine.
Lowell