... This is less than the 2" minimum recommended in the EIS install manual. Is this mounting location going to cause early probe demise?
Thanks,
Thank you for bringing this issue up as it gives me a chance to share some information about probes, EGT probes specifically.
As we all know, a thermocouple is when two dissimilar metals are joined together. This causes a small micro voltage to be generated. When temperature is added, the micro voltage being sent to the instrument changes. This is how we calibrate our temperature systems.
Unfortunately different metals contract and expand at different rates. Other manufacturers make grounded probes, which lock together the metals (three) in the tip of the probe. This “locking together” of the metal does not allow for any movement when the metals expand and contact during temperature cycles under normal use. This causes the metals to work against each other, which causes fracturing of the metals in the probe tip. This means a probe failure.
What we do with our "ungrounded" probes is allow for this movement during expansion and contractions with heat cycles. We do this by insulating the two material junction in ceramic without ever going to the SS material of the probe it's self. This “pure” thermocouple junction is more accurate, more stable, less susceptible it engine ground noise, and more durable than any other probes in General Aviation. You see, there is no fatiguing effect with heat cycles.
Our probes can be used on any manufacturers engine temperature equipment utilizing K thermocouples for this reason.
As a note: What one other probe manufacture has chosen to do to combat indication issues, and longevity is two fold.
1. Spend through the nose on marketing praising their probes and discrediting our probes. 2. Specify their installations to be 3-4” down the exhaust tube. (Buying time here and nothing more) The “grounded” probe will fail anyway sooner or later depending on the degree of use.
We on the other hand specify 1.5” down from the exhaust flange. In the flame of the exhaust. If installed correctly, and kept tight, our EGT probes should outlast your new exhaust. Or last as long anyway.
I hope this information is found to be useful and please let me know if there are any questions.
Matt