CHT ring and wiring

lenene

I Am nuts for aeroplanes
Joined
Jul 10, 2013
Messages
49
Location
St. Louis MO
After buying used plane with D180, I need to reduce excess wiring. The Dynon harness is way too long and I want to shorten both the CHT and EGT wires. Where can I cut and splice without affecting operation and accuracy?
Also, one of the CHT spark plug rings broke off the end, but it still does register a value from the stubs. If I purchase a replacement CHT probe, will it just be the shielded length from the ring to the joint with the brown covered wiring going to the D180 box, or the whole thing? thanks
 

Dynon

Dynon Staff
Staff member
Joined
Jan 14, 2013
Messages
14,232
Location
Woodinville, WA
Generically, anywhere except for where there's a temperature change across the junction you're about to create. So, don't break the wire up before/after the firewall, for example. Any temperature change across an EGT/CHT junction that isn't make of the same thermocouple material that the wire is made of will mis-read by the amount of that temperature change.

Our CHT probes include just the one or two feet of wire that joins to the main D180 harness, which is about 6'. If the airplane was built using Dynon harnesses, the joint between the two will be at a spade connector. If it's a manufactured aircraft, all of the above may not be true - the harnessing and connection methodology may vary.
 

lenene

I Am nuts for aeroplanes
Joined
Jul 10, 2013
Messages
49
Location
St. Louis MO
If I read the answer correctly, I can cut, and remove a section of either the shielded wires that ends at the CHT ring or EGT probe, AND/OR the wires (yellow, white, red) that travel from the spade connector encased in the brown sleeve going to the D180 25 pin EMS input.
I just must ensure my connector or the furnished spade connector of the Dynon harness does not reside at a spot with a temperature gradient, such as at the firewall...correct? thanks for your help... :cool:
 
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