Hello
My aircraft is equipped with 6 EGT ALCOR probes, which are ungrounded (PN 86317 or 86343). They have seen their price increased, and from expensive have become ridiculously expensive (over 400$ for the Best Buy).
Looking around, I have found one brand making EGT ungrounded probe, Electronics Infernational (EI), with their P110-F FAST REPONSE probe.
The specific omega style connector I have could be adapted to them.
My questions are:
- do you know those probes ?
- do you think I can switch the next failing probe to P110 on my installation (G1000) without disturbing the engine monitor interface ?
- is it a problem to mix different probes model ?
Thanks for your help !
May I ask @wigglyamp his point of view on this topic ?
Many anticipated thanks.
By the way, according to EI support, the two varieties of their P110 – fast response and slow response – are generally compatible, the slow response one being more durable.
When EI first got going, they were selling quite a thick EGT probe. They claimed it would last a lot longer than the JPI one, which was undoubtedly true because the JPI ones seem to last only a few hundred hours (much depends on usage I am sure). But the thicker probe was slower responding.
Have tried to contact Garmin to ask them about compatibility with GEA71
Answer is “Cessna holds the Type Certificate, only them know…”
Will report what I find on the topic.
I asked EI why their ungrounded probe was $100, while Alcor’s one is $400. Here is their answer:
We design and build our own probe in house, this is how we keep prices so low. I think we make the best probe in the Industry.
Peter wrote:
Something similar came up before here.
Yes, at the time, I wondered if I could switch to grounded probes, which I didn’t do.
But, two new probes later, and with prices still going up, I thought I might give another try.
All the help I can get is welcome, to identify compatibility between Garmin GEA71 (engine monitor unit) and P-110 probe.
It’s only a dumb thermocouple 
Any ungrounded probe of the same type (J or K) will work, subject to suitable mounting etc.
Someone is charging $400 “because they can”. Could also be that they make very few of some obscure product which is contracted out to somebody who doesn’t want to do it anyway…
GA suffers a lot from this very small batch production issue. Years ago I saw some details of a business for sale in the USA, consisting of an 80 year old guy sitting in a shed, making annunciator panels for a particular very old US GA brand whose trademark is an upright vertical stabiliser He was still turning over six figures, which is not bad with a ~90% margin. Throw in anal interpretations of type certificate “requirements”, an A&P who won’t (possibly can’t) read, and you have a great business model
Update: P110F works with G1000 engine monitor.
But:
- they are less responsive than Alcor 86317/86343
- they under read by 40-50°F on the instrumentation compared to Alcor measurement
they under read by 40-50°F on the instrumentation compared to Alcor measurement
That would concern me. It might be a ground loop i.e. the probe output voltage is being reduced by a voltage drop in the ground connection caused by some other current flowing. Can this be reproduced with the two probe types alongside each other, wrapped up in a rag? It could also be a different type of thermocouple is involved (J vesus K etc – there are about 7 types).
