While replacing spark plugs on my '97 XK8, I noticed the light-gauge purple & green wires connected to one of the coils had sections of missing insulation which were down to bare copper. At first I thought the wires had been pinched during engine assembly. But as I began to tape up the bare wires, it became obvious the insulation had become brittle and was flaking off. When I got to the other side of the engine, same thing, on the coil closest to the dash panel. This could obviously present a real problem if the bare wires either touched each other, or became grounded. Something for you folks to look out for when changing plugs. Evidently, the supplier who built the wiring harness chose an insulating material not sufficient to withstand long-term service and heat.

 

Welcome to Jaguar.

Most interesting to find that our S Types, and X300 are not alone.

I am aware of this from the years with the "real engine", V12, and the EFI loom that did just that and reeked absolute havoc.

I will be taking the inlet off the Black Beast during the Christmas break, and among other items will be renewing the wiring to those 3 coils, VVT solenoid/etc, with some Wurth Hi-Temp stuff.

 

mrfixit, as I see things, you have 2 options:

1) obtaining a new engine wiring harness to remove the deteriorated wiring. The twist to this is if you are feeling froggy, you can build your own wiring harness/remove and run new wires where needed. The question becomes how comfortable are you with wiring and is the time required to make the new harness worth the savings. That is something that only you can answer.

2) obtain some heat shrink and then you can open up the wiring harness (removing the tape off of the wiring) and then pulling 1 wire out of the plug at a time and running tubes of heat shrink over the wiring to add a layer of insulation back in. If you look around, you are going to find that there are 2 kinda of heat shrink out there. You have the normal heat shrink like you will find at most places (Radio Shack/Lowes/etc) that is a really thin tube that shrinks right down on to the wire, adding very little bulk to the whole thing. You then have stuff that I will simply call Raychem (this is the manufacturers name). This stuff is heat shrink on steroids. I use it at work to survive a nuclear reactor disaster (yes, it will do that). It is a bit more bulky, but it also have an adhesive on the inside that would seal the ends of the wires and not allow water under the heat shrink, leading to failure due to corrosion of the wiring (like the cheaper heat shrink can allow to happen). If you are thinking about the heat shrink option and want to know more about the Raychem stuff, let me know. I can feed you a lot of information. As I see it, the light/cheap heat shrink is good for inside the cab of the car, but for the engine bay (and its environment), the Raychem is the only way to go for a long term fix.

 

I believe aircraftspruce.com probably carries the Raychem line or similar. Their print catalog is a must have. Weighs a ton, but shipping is free once you put the catalog in the shopping cart.

 

Agree...as a former A&P (Airframe and Powerplant) wrench...the Aircraft Spruce catalogue is a must-have addition to the garage library...you may never need to put an avionics stack in your cat ("XJ8, turn left to intercept localizer, you're cleared for the ILS 6..." LOL) or have a need for landing gear bungies, but, their AN- and MS- hardware selection is WAY beyond what you will find anywhere. And metal working tools, and ...

Use them extensively when restoring my Lotuses. Amazing how nice restos look when you are using AN-quality and stainless hardware rather than what was in the bins at Sears Hardware or Pep Boys (if they even have it....)

(Just a suggestion...don't use Grade 8 bolts on suspension parts...they are sacrificial; using them will transmit energy instead of deforming...sending the shock further into the structure than it was meant to handle...)

 

I noted this post in regards to the heat effected wiring insulation deteriorating. XK8 1997....Does any company have replacement looms available??

 

Found this item as a repair, Does anyone have an idea of the correct wire description code for these coil connector looms approx 1mm 6 strand copper
This kit could be a help to the USA Jag guys, they dont ship down under, go figure......97 XK8 2 wire fitting
https://www.partsgeek.com/catalog/19..._connector_kit