Engine monitoring sensors arrived today from Dynon. I decided to start with CHT sensors since they looked like they would be easiest to install. Wrong! Just screw in adaptors and locked in probes. What could be easier. Unfortunate my adaptors did not want to go into the hole in the cylinder head that it was designed for. As you can see in the pictures below, there is a small stud that stick out on the adaptor and the porbe has a bayonet type connector that locks the probe into the hole. The studs on all of mine seem to be about 1.5mm to long and after about a quarter of turning they all would hit the cylinder fins. Called UL, Dynon and Zeniith and of course no one had ever seen this problem before. After much discussion and sending prictures no one had any ideas on why they did not fit. So with that said, I took it upon myself to grind down the studs about 1.5mm so they would screw into holes. This does not leave much of the stud sticking up higher than the connector but at least they are installed and should work okay.