EGT/CHT terminal part numbers?

[gtae07]

I somehow managed to misplace the ship-side crimp terminals that are supposed to be used to connect the CHT and EGT probes to the wires. Anyone have a good part number/link where I can buy some more? I usually look on Digi-Key for such things but there are so many choices I don't know if I'd find a compatible one.

 

[RV8JD]

Many folks have had difficulties with troublesome/failed Dynon CHT & EGT probes, including me. It has been attributed to the standard spade/crimp connectors that come with the Dynon probes. They (and I) have swapped them with either OLC-2 or OLC-1 connectors and have had better luck with CHT/EGT probe longevity.

Cheaper from EI directly (and includes a hex wrench):

OLC-2 Connector | Electronics International | Aircraft Engine Instruments

The OLC-2 eliminates the need for soldering, crimps, and expensive connectors, all while creating a perfect connection between two wires. The two wires are stripped 5/16"” and then slid into opposing ends of the OLC-2. A set screw on each side of the OLC-2 is gently tightened. The OLC-2 can...

iflyei.com

But if you like ACS:

EI Wire Overlap Connector / Splice Olc-2 | Aircraft Spruce

EI Wire Overlap Connector / Splice Olc-2 The OLC-2 eliminates the needs for soldering, crimps, and expensive connectors, all while creating a perfect connection between two wires. The two wires are stripped 3/8 and then slid into opposing

www.aircraftspruce.com

Instructions:

https://iflyei.com/wp-content/uploads/OLC-2_Instructions.pdf

 

[Stevec]

+1 from me for the olc connectors. I was having constant problems with CHT readings. I bought new probes but the problems continued. I replaced the spade connectors with the olc connectors and no problems since.

 

[GKC Aviation]

Throw the Dynon supplied ones in the bin.
You will be chasing faults till the end of time with them

 

[jakej]

Just a couple of points here given that I’ve had a bit of experience with over 70 installs .
OLC’s work,but are fiddly with the very small grub screws & the joints need heat shrink to insulate them. Those very small grub screws can be very hard to find if you drop them.
Correct re the pink colored spades - I always throw them in the bin - use the RED colored (real aviation grade?) ones from Amp (or TE as they are now known ).
I also spray them with contact cleaner before crimping with no issues since I started doing that & only had to replace 2 x EGT probes up until then - due to customers bending them too much YMMV

 

[greentips]

Good information jakej. I have the CGR30 and initially had the same trouble with the OL2s and the loss of the screws. I solved the screw loss by working over a sticky pad used at the entrance of clean rooms to collect dust cut to fit the work area. The screws fall to the sicky pad and are easy to find. The second thing I did was to magnetize the hex key to hold the screw in place. and I made a gauge to strip the wires to the right length. After that, no more flakey EGT/CHT readings. I do like the idea of the shrink wrap to keep dirt and whatnot out of the connectors. Now, I have to ponder which connectors I'll use...I was going to go with the Dynon supplied, because of the issues with the OL2s, but now, I may reconsider this and go with the OL2s. And spray them with contact cleaner before I use them.

 

[gtae07]

Hm. I wonder...
Do the connections have to be thermocouple specific or will any old connector work? I have extras of a lot of different ones (weatherpak etc). I could also order some specific ones, or get knife disconnects, or use D-sub pins with heat shrink over the joint...

 

[jakej]

Any old connector won’t do - dsub pins/sockets, thermal or olc will work - I use the spades as per post #5 above, not el cheapo types, as they are much more robust ie they are made of thicker plate tinned material. The other benefit is you don’t need to change out the connectors on the probe end if you go this route. Much easier & simpler

 

[Stevec]

My thoughts were that it was not the actual spade connector itself but the crimp on to the sensor wire that was causing the issue. I don’t know if the types of wire and crimp involved could be causing the issue but it seems strange that with all the spade connectors used in the automotive industry etc that there are no major histories of failures and generally it’s a reliable means of connection.

 

[greentips]

I was wondering that myself. I use a calibrated crimp tool frame and die and haven't had problems with avionics using these methods. But most of my connectors are PIDG or AMP with an MS number.

 

[jakej]

My thoughts were that it was not the actual spade connector itself but the crimp on to the sensor wire that was causing the issue. I don’t know if the types of wire and crimp involved could be causing the issue but it seems strange that with all the spade connectors used in the automotive industry etc that there are no major histories of failures and generally it’s a reliable means of connection.

IME it’s the actual crimp section of the spade that’s mainly the issue (besides some people using incorrect crimpers) as the crimp section metal body is only half what it is when using the type I mentioned. The probes Dynon supply are very unlikely to be a problem, I’ve connected several hundred of them & only had to replace ~ 2 NOT due to manufacturing issues as mentioned in earlier post.

 

[Stevec]

Jake my last CHT probe experience was an erratic CHT reading. I have replaced 3 probes in the past. I transferred the probe to another cylinder and the problem transferred. I then swapped to the OLC connector based on other’s recommendation and the problem was resolved. In the last 40 hours there has been no reoccurrence of any CHT or EGT problems so that was the basis for my assumption.

 

[jakej]

Jake my last CHT probe experience was an erratic CHT reading. I have replaced 3 probes in the past. I transferred the probe to another cylinder and the problem transferred. I then swapped to the OLC connector based on other’s recommendation and the problem was resolved. In the last 40 hours there has been no reoccurrence of any CHT or EGT problems so that was the basis for my assumption.

Hi Stevec - there are so many variables here. The early supplied thermo-couple wiring looms were using a single, very thin, conductor & same applied to the probe side resulting in very poor junctions (we are talking about millivolts here so the junctions are critical to get reliable results). I used to strip the single conductor back enough to allow me to bend the wiring back on itself 3 times which resulted in much more wire in the crimp allowing a better reliable junction.
Some time ago Dynon started supplying multi conductor wires however some were still having issues due the earlier single conductor probes, now both looms & probes have multi conductors.
Once I woke up to where the basic cause lay I found most 'issues' could be resolved easily without the expense/hassle of replacing probes.