Folks:
Interesting problem - My IO-360-A1B6 has an Eagle EMS electronic ignition & fuel injection system from Precision Airmotive. (This was a low-production experiment for PA, and is no-longer-supported.)
Anyway, the CHT's from the rear two cylinders are input data to the system, so it has some special probe adapters for the CHT ports on these cylinders. My AFS engine instrumentation set-up cannot share these probes, so there are 10mm gasket-type CHT probes under the adapters. The front two cylinders use normal CHT probes for the EMS.
As you might imagine, there are radically different readings from the two types of probes and installations, with the gasket probes on 3/4 usually reading about 60-70? less than standard probes on 1/2. I can extract the readings from the EMS probes on 3/4 via laptop and see that they are actually ?in line with the front two probes.
So while I am pretty sure that the engine is doing fine, my CHT display in flight is unnerving - usually showing ~310-320? on 1/2 and 250? or so on 3/4. (Note that during taxi-out, where there is minimal airflow through the cowling, all 4 probes match pretty well.)
My options would seem to be
So I was wondering if anyone has experience with 18mm CHT probes under the spark plugs? Do they last? How many times can you check the plugs before they won't seal? Do you have to, or can you, anneal them, or are they just throw-aways?
Thanks,
Andy
Interesting problem - My IO-360-A1B6 has an Eagle EMS electronic ignition & fuel injection system from Precision Airmotive. (This was a low-production experiment for PA, and is no-longer-supported.)
Anyway, the CHT's from the rear two cylinders are input data to the system, so it has some special probe adapters for the CHT ports on these cylinders. My AFS engine instrumentation set-up cannot share these probes, so there are 10mm gasket-type CHT probes under the adapters. The front two cylinders use normal CHT probes for the EMS.
As you might imagine, there are radically different readings from the two types of probes and installations, with the gasket probes on 3/4 usually reading about 60-70? less than standard probes on 1/2. I can extract the readings from the EMS probes on 3/4 via laptop and see that they are actually ?in line with the front two probes.
So while I am pretty sure that the engine is doing fine, my CHT display in flight is unnerving - usually showing ~310-320? on 1/2 and 250? or so on 3/4. (Note that during taxi-out, where there is minimal airflow through the cowling, all 4 probes match pretty well.)
My options would seem to be
- Replace the 1/2 CHT probes with similar 10mm gasket type probes and a big bolt in place of the EMS mount,
- Replace *all* the probes for the AFS display with 18mm gasket probes under the spark plugs.
So I was wondering if anyone has experience with 18mm CHT probes under the spark plugs? Do they last? How many times can you check the plugs before they won't seal? Do you have to, or can you, anneal them, or are they just throw-aways?
Thanks,
Andy
