Date: Wed, 10 Jan 2018 07:24:17 -0800
Reply-To: Steve Williams <sbw@SBW.ORG>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Steve Williams <sbw@SBW.ORG>
Subject: Re: Multi Conductor Shielded Automotive Wire Temperature Rating
In-Reply-To: <CAB2Rwfidkr_2+ZZ65i7k-tYNUUYBkZAkxDqFwweaz4mdwMJjng@mail.gmail.com>
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On 1/9/2018 8:54 PM, Neil N wrote:
> I've been looking hard for a solution to my corroded O2, knock and crank
> position sensor wires.
I'm spoiled by my days in avionics vocational school and maintaining my
own aircraft, so I use aviation wire in the camper. Here's a Tefzel
shielded, three-conductor, shielded, 22 AWG wire, available for $1 per
foot from B&C Specialty Products:
http://www.bandc.aero/22awgshieldedtriowhitetefzelwire.aspx
For signal wire, I expect 22 AWG is adequate. I've used it for an
aircraft fuel flow and oil temperature sensor, for example. In the
camper, I use shielded 22 AWG for the stereo and unshielded 22 AWG for
the ammeter shunt.
Tefzel is a much tougher outer jacket than you can get outside of
aviation. We use it in aircraft engine compartments without further
protection. When it runs near exhaust components or cylinder heads, we
wrap it in firesleeve for extra thermal protection. B&C doesn't carry
firesleeve, so here's Aircraft Spruce:
http://www.aircraftspruce.com/menus/ap/hose_firesleeve.html
B&C also sells terminals and splices of much better quality than
available most places. These have a two-stage metal crimp, so used
properly the conductor is captured, then the insulation is captured for
strain and vibration relief:
http://www.bandc.aero/electrical-terminals-splices.aspx
And an inexpensive crimp tool that makes it easy to achieve gas-tight
crimps for longevity, especially in the engine compartment:
http://www.bandc.aero/pidgstylecrimptool.aspx
I've met Bill and Celeste Bainbridge, who run B&C, and I like buying
from them. It's fun to browse the rest of their web site. Need a
lightweight alternator for your homebuilt aircraft?
Regarding shielded wire, remember to always ground all signal shields at
only one point. Signal shields should be grounded near the instrument
(in this case, the ECU?), and left open at the sensor end. Shields
grounded at both ends invite noise from a ground loop. Here's
step-by-step instructions for creating a clean shield pigtail to crimp a
connector on:
http://www.aeroelectric.com/articles/pigtail/pigtail.html
That approach is simplified by using solder sleeves. They can be
expensive, but Digikey sells them in small quantities. Be sure to check
the diameter of the sleeve against the diameter of the shielded cable
plus a pigtail:
https://www.digikey.com/short/q8phf1
