EI EGT Probes - life span, fast vs robust

[Marc_B]

I have a MVP-50 that was installed in 2018 in my M20K.  Looks like it was installed with the fast response probes (P-110-F).  Since then the #5 EGT probe replaced 1/27/21, #4 EGT replaced 2/11/22, and #3/#6 EGT replaced 5/17/23.  Now my #2 is erratic and probably going out.  I'm curious what others are seeing as the normal life expectancy for the fast probes.  Marching through half the probes in the past 2 years makes me wonder if I should just replace them all with robust probes P-110-R vs just keep replacing on condition with same?  Can you mix and match? i.e. can I start to replace with robust each time one burns out and have robust and fast mixed until then.

@oregon87 Not sure if you have any other recommendation or guidance?  Are the EGT probes considered consumables and have a 3-5 yr lifespan?

[oregon87]

41 minutes ago, Marc_B said:

I have a MVP-50 that was installed in 2018 in my M20K.  Looks like it was installed with the fast response probes (P-110-F).  Since then the #5 EGT probe replaced 1/27/21, #4 EGT replaced 2/11/22, and #3/#6 EGT replaced 5/17/23.  Now my #2 is erratic and probably going out.  I'm curious what others are seeing as the normal life expectancy for the fast probes.  Marching through half the probes in the past 2 years makes me wonder if I should just replace them all with robust probes P-110-R vs just keep replacing on condition with same?  Can you mix and match? i.e. can I start to replace with robust each time one burns out and have robust and fast mixed until then.

@oregon87 Not sure if you have any other recommendation or guidance?  Are the EGT probes considered consumables and have a 3-5 yr lifespan?

Hi Marc -

We suggest our P-110-R EGT probes in turbocharged applications as the thicker probe (.187" diameter vs .125") typically results in a longer life span.  If you would like to contact me directly at support@iflyei.com, I will generate a return authorization number for you to reference when shipping us  your current EGT probes.  We will be happy to exchange them for you at no charge.  Worth noting, the holes in the exhaust may need to enlarged a bit for the new probes.  

[Marc_B]

@oregon87 Thanks for the help!  I'll email you now.

[jamesm]

  The trick is that if you buy 2 EGT probes then the replacement EGT probe wont burnt out, a Murphy's law sort of a thing. When I buy one  EGT temp probe it almost always inevitably goes bad a short time after the replacing EGT probe installed goes out.

[philiplane]

what is the failure mode? Is the tip burning, or does the probe go offline? EGT probes are often replaced due to connection issues, and not a fault of the probe itself. 

[Marc_B]

@philiplane current probe may be just a connection. Others were inspected and connections were cleaned and replaced but issue persisted. What I’ve seen on monitor data were erratic readings, readings off by several hundred deg, and flat readings close to zero. I don’t know what DVM showed on probes but my shop said they needed to be replaced. 
I reached out to Dave at EI and he’s gonna get me squared away. Thanks for the help @oregon87  Fast response probes were originally installed rather than robust; but sounds like robust probe likely a little more durable/thicker and a better match for turbo. It’s only been EGTs and not other probes and no other connection issues.

[philiplane]

erratic readings are nearly always caused by poor connections. The only time they are caused by the probe itself, is when the outer tip starts to burn through and torches the thermocouple inside.

The EI barrel style set-screw connectors are noted for intermittent connections, because virtually no one installs them correctly.  

[MikeOH]

On 6/24/2023 at 11:53 AM, philiplane said:

The EI barrel style set-screw connectors are noted for intermittent connections, because virtually no one installs them correctly.  

@philiplane

I'd appreciate it if you would elaborate on how to install them correctly (and how they are typically installed incorrectly)

Thanks!

[philiplane]

1 hour ago, MikeOH said:

@philiplane

I'd appreciate it if you would elaborate on how to install them correctly (and how they are typically installed incorrectly)

Thanks!

they come with specific instructions and an allen wrench. Those instructions are also on the EI web site.

People over-torque the set screws, setting up wire breakage in short order, they don't strip the wires correctly, leading to poor contact with the set screws, they also use cheap strippers that leave cuts in the wires, also setting up near term failures. And they don't support the connections properly with zip ties or clamps, so vibration exacerbates all the baked-in problems from Not Reading The Instructions.

[A64Pilot]

If you use the barrel connectors dip the stripped ends of the wire in DC-4 before you insert them because they aren’t waterproof.

[Marc_B]

I replaced my CHT probes with all robust probes thanks to EI. Time will tell the durability but my readings all are now within a degree of each other at power in and I can’t really tell a difference between the rapid and the robust in flight. Fingers crossed no more probe replacements for quite a while!

[kris_adams]

I think there was a bad batch of probes back around this time from EI (at least that's what I was told for the reason my EI probes went out so much).  I originally had the fast probes on my CGR and pretty much all of them went out and were replaced, then those were replaced again with the "robust" or whatever they are called.  I had better luck with the 3 round though still had issues.  Fwiw, I couldn't really tell any operational difference in the fast vs "robust/slow".  Of course I've had all of mine removed now but that's a whole other story. -K