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I have had 3 EGT probes fail. These were the MGL probes, but they are the dirt simple hose clamp and a probe setup that can be found from various engine monitoring suppliers. Is this common? I did not expect to to have one failure in 150 hours much less three. Just wondering if I got a bad run, or if the high temperature environment causes these to fail.
Hi John B! Definitely 3 probe failures in 150 hrs is excessive and as you say, even 1 in 150 hrs is abnormal. I originally had a Grand Rapids Technologies EIS 6000 and I used their installation kit and EGT probes. I later switched out the EIS 6000 for a MGL Xtreme mini-EFIS and mini-EMS. I retained the GRT probes and they worked great with the MGL equipment. I think I've had only one probe failure in 800+ hrs, and replaced the failed probe with another GRT EGT probe. Don't know if that's either good luck or GRT sells a superior probe, but it works for me!
I also suspect that probe placement could shorten a probe's lifespan - I "think" my probes are about 120 mm from the exhaust ports. The recommended placement is likely in the engine installation manual or Nick at Arion Aircraft could verify the proper distance.
The Gen 4 engine ships with some pulled rivets in the EGT probe locations. Just drill out the rivet, enlarge the hole and install the probe. I will check and see what the distance might be. I might also check on the GRT probe. I may have just received some poorly made probes.
The pre-drilled holes are a good improvement (on the earlier Gen engines you have to measure and drill the EGT probe holes) - the distance from the exhaust ports and location on the exhaust headers will be "standardized" by the factory and that should help make EGT's more relevant to compare with Jabiru's recommendations.
Could it be the wires failing and not the probes themselves? If that's a possibility, maybe try securing them differently so the replacements don't vibrate in the same way.
I've had 2 fail in 400 hours.