Wiring Loom for JPI 740 EDM for LongEZ

[paulgsmart]

Hi All,

I have a LongEZ with the 0235 Lycoming engine.

I want to put a JPI 740 EDM (with 8 sensors and fuel flow unit)  into the instrument panel.

Does anyone know the Loom Length I will need to order ???

Cheer

Smarty

[Kent Ashton]

Nobody routes wires the same way.  It is probably easiest to route some cheap electrical wire through the airplane as you wish, remove it and measure the length.  JPI stuff is expensive.  I usually buy the wire on ebay and make my own wire runs.  CHT bayonets and all the sensor wires are easy.  EGT probes you might have to buy.  Omega.com sells the correct wire for EGT/CHT.

[Kent Ashton]

For example, a 4-pack of JPI CHT sensors with pigtails is $408.  Ouch.  And that doesn't include the wire loom to get to the instrument.

 

You can buy the wire from Omega, use a common brass fitting threaded for a Lycoming bayonet mount (the pitch which I have forgottten at the moment), a spring and a bit of silver solder and make one (pics) that works exactly the same for maybe $30 for four of them.

 

Edit: how to make: The pigtail wire is Omega EXGG-J-16 Iron/Constantan. I use a lighter gauge yellow-covered Iron/Constantan wire for the loom run.  The fitting you will have to figure out for yourself but it is a common fitting here in the U.S.  Buy some silver solder and flux.  Strip off the ends of the wire, twist them into a ball and silver solder.  Slide on a spring and the fitting.  The spring is sized to press the balled up CHT wire against the top of the bayonet hole.

Edited November 11, 2017 by Kent Ashton

[Kent Ashton]

I would also be tempted to try these $12/each EGT ebay probes vs the $408 JPI set.  It appears they are depth-selectable.  If the threads fit your boss, you're in business. 

https://www.ebay.com/itm/Universal-K-Type-EGT-Thermocouple-Temperature-Sensors-For-Exhaust-Gas-Probe-/251997239125

 

If the link gets old, search ebay for K type EGT sensor or probe.