Experiences using ring type CHT probes

My new Aerosport IO360 is equipped with a Precision Eagle Fuel and Ignition system. This system uses #3 and #4 CHT positions as inputs. I now have a Dynon EMS system that is short two cylinders for temperature monitoring and display. I looked into using dual element CHT probes but the Eagle system uses thermistors not thermocouples in its probe so that rules that option out. I remember using the ring type thermocouple for CHT measurement years ago in snowmobiles and I see that I can purchase 18mm ring type T/C from ACS. I assume that the values the EMS will see will differ between the conventional CHT measurement spot and that of the sparkplug ring. Does anyone have any experience using this type of temperature element that they can share with me?
Thanks
Cam Andres
RV9A with Aerosport IO360
Building log at
www.tailcreek.com/tcaviate

I had them before updating to the GRT EIS.

Hated them. It was always a pain in the a$$ to tighten the plugs with them. You want there to be very little slack in the lead because it's an airplane and we don't want things flopping around. If you don't do it just right you end up putting tension on the lead then you start over.

I would avoid them if I had the option

Washer vs. Screw-In CHT Probes

Concur with the above. But more importantly in my experience, the washer type CHT probes read ~50 degrees cooler than the CHT well screw-in probes. I believe the screw in probes give a much more accurate temperature. Having used both on the same type engine, I elected to go with all screw-in type. There are some applications where the washer type make sense, just have to be aware of the limitations on accuracy and maintenance considerations.

Happy Flying,
Reggie

The literature I've read claims 25 degrees lower reading for the gasket thermocouples versus the bayonet type. I don't think accuracy is an issue, just a different temp at a different location.

FWIW, not knowing any better I bought the ring type two years ago and haven't had any serious issues with them. They do require care when removing/installing plugs, but so far i've been okay. I keep telling myself i'll replace them with bayonets at some point, but so far haven't had a need to do that.

Thanks for your comments

It sounds like the ring type T/C elements can be inconvienient when handling the plugs but considering I am only dealing with two elements, not four or six it shouldn't be a major issue. I really don't have any other easy options if I want to get all my CHT readings in front of me on the Skyview screen. I believe the #1 criteria is repeatability of the measured value so I can spot any CHT trend away from what is "normal".
Thanks for your comment
Cam Andres
RV9A with Aerosport IO360
Builders Log
www.tailcreek.com/tcaviate

I'm pretty sure if you have a Lycoming that every cylinder has a bayonet-style mounting hole for a CHT probe, so you could still go either way.

Hello Rob,
No the threaded CHT holes are used up on cyl #3 and #4 by the Eagle Fuel and Ignition controller. My initial post described the issue.