Finally managed to buy a edm700 cable, connect it, and actually download engine logs. Did take a while to make it work – talk about oldschool software:D
Anyway, I downloaded all the stored logs and uploaded them into the savvy aviation website.
Any ideas why would one cylinder be running so much cooler?
Any other insights can be drawn about the engine health from these graphs before I buy savvy experts service?
https://apps.savvyaviation.com/flights/shared/flight/8250527/046b2f52-1b7f-4c59-a545-7d87b1bc59fc
Unfortunately no FF sensor with edm700, so the data might be somewhat limited but happy to share more logs.
CHT differences between cylinders generally come from placement in the airflow. When a single sensor is used and displayed in the cockpit, it’s installed on the worst cylinder (back left or back right), so that the avoids overheat based on the “worst” cylinder (i.e. the hottest).
On many engines, incl my IO540, one CHT probe is different: the built in CHT instrument has taken the bayonet slot and the EDM gets an substitute screw on probe – which underreads and cannot be corrected in the edm700. So its appears about 100 degrees cooler than the rest. In my case it is also No1.
The other front row cylinder No2, with a normal bayonet, but direct airflow is actually cooler by about 30-40 degrees.
ch.ess wrote:
On many engines, incl my IO540, one CHT probe is different: the built in CHT instrument has taken the bayonet slot and the EDM gets an substitute screw on probe – which underreads and cannot be corrected in the edm700. So its appears about 100 degrees cooler than the rest. In my case it is also No1.
wow I never realized that this is super useful to know. Mine is also IO540, so it is likely exact same reason
ch.ess wrote:
the built in CHT instrument has taken the bayonet slot and the EDM gets an substitute screw on probe
That is absolutely right, likewise in my installation, but I never realized the effect on the measured temperature. Will check it out, too. Thank you for pointing that out.
Installations where you have an edm700 or similar, and retained the old CHT gauge, are very likely to have this problem.
The legal way to solve it involves getting a monitor with a “primary” STC. Other ways involve being pragmatic 
Another IO540 owner with a a “cooler” #1 due to the factory CHT probe installation here.
As Peter said, the best solution would be to use the bayonet probes on all cylinders and accept the consequence on the primary/original CHT gauge.
…my edm700 set came with 5 bajonet probe and one screw-on type as default :-(
So without additional downtime for ordering an additional bajonet probe from JPI, I could only finish as it is now.
That said, it does not affect my monitoring much, you just know your correct numbers…
