Ign Harness rebuild

dod03-52 · Post by **dod03-52** » Mon May 25, 2009 7:52 am

After searching on the "Internets" for weeks, I found 5mm diameter ign wire to rebuild the shielded harness instead of buying one for $160.00!!
$20.00 for 20 feet Enough to do 3 harnesses. We used to rebuild these for aircraft engines all the time. If all goes well I will let you know where to get the wire.

oilleaker1 · Post by **oilleaker1** » Mon May 25, 2009 8:05 am

I think this must be a common problem since my plug wires have the outer rubber falling off. I was wondering if the inner is still good or if you could re-cover them. Your idea sounds interesting. Special tools to re-crimp the ends? Are you thinking of doing others for people? John

dod03-52 · Post by **dod03-52** » Mon May 25, 2009 8:27 am

The end connectors are called "cigarettes" on aircraft engines and they just "screw" into the ends of the wires---no tools needed, The outside rubber is another problem==they are put on before the ends are soldered to the braided hoses---any one got ideas about the outside rubber replacement?

Post by **wesk** » Mon May 25, 2009 9:16 am

This topic comes up often. The outer chaff protection is a molded rubber sleeve and actually only prevents the stranded steel sleeve of the harness from rubbing grooves into things it lays against. It is not an indicator of the internal rubber part's condition. This is best determined by inspection. Or at least by measuring electrical isolation using an ohm meter between the core wire and the stranded steel sleeve. A confirmed open circuit while wiggling the lead will indicate it is good to go for shorts. A quick check for excessive resistance or an open circuit between the two wire tips will assure the lead wire is in good shape.

The large industrial fuse size wire shrink works well to replace the deteriorated outer rubber sleeve.

The reference to aviation shielded harness construction is true in that the basic design is similar but most modern aviaition harness are flexible shield covering the inner wire directly and not as a conduit. The modern aviation harness uses 18mm plug attachments.

This is what the modern aircraft harnes termination looks like:

Magneto distributor block attachment

Spark plug end

MODIFIED · Post by **MODIFIED** » Wed May 27, 2009 5:43 pm

wow, you have the potential of making alot of new friends should your rebuild work. BTW, I am experimenting with liquid EPDM rubber for possible repair welding on the outer rubber jackets of the stock wires.

please let us know your conclusions .... thank you.