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John Grieve
Experienced User
Username: john116

Post Number: 15
Registered: 4-2012
Posted on Friday, 25 October, 2013 - 06:45 am:   Edit PostDelete PostView Post/Check IP

Hi - a number of the wires in the engine bay of my Silver Shadow II are a little 'crispy', I guess from 34 years of heat, petrol/oil fumes etc. Mostly confined to the ones that run across the top of the engine, and the ones that run behind the radiator grill.

I have found if you bend them just slightly, the insulation just breaks where you've bent it. So am treating them more carefully obviously to reduce cracking.

Just wondering what you guys do re your engine bay wiring.
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 659
Registered: 6-2009
Posted on Friday, 25 October, 2013 - 07:20 am:   Edit PostDelete PostView Post/Check IP

John,

It's one of two things (or three, if replacing all of the wiring is something you're willing to do):

1. Exactly what you're doing. Handle any wires that must be touched with care, in particular, don't do any significant bending or kinking.

2. Partial replacement of segments that have accidentally been "de-insulated" via crumbling.

I have, in a few rare instances, just used electrical tape if a very small region of insulation was cracked off because of flexing or chipping from being hit. What I'll generally do, if there's extensive insulation loss, is to solder new wire on to the old very near to where it enters the loom (or as close as is practical) so that what will actually be worked with in the foreseeable future will have fresh and flexible insulation.

Of course, in most cases you can't find wire that has the same primary color and tracer at hand, unless you've got a personal collection or a parts supplier nearby that handles an awful lot of wire variants. I put masking paper tags noting the original color/tracer of the wire when I have to replace with something that doesn't match. It's amazing how well those tags have held up over years of service.

Brian
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Geoff Wootton
Grand Master
Username: dounraey

Post Number: 333
Registered: 5-2012
Posted on Friday, 25 October, 2013 - 11:11 am:   Edit PostDelete PostView Post/Check IP

John

I also do as you are doing i.e. I try not to disturb the wires and use insulating tape if possible. Ultimately I replace wires if they are too far gone.

One thing to look out for is the two wires that enter the choke solenoid can lose their insulation at the point where they enter the cover plate. If they short to earth they can take the ignition circuit out. I've documented the problem in entry http://au.rrforums.net/forum/messages/17001/13329.html.

Geoff
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Randy Roberson
Prolific User
Username: wascator

Post Number: 164
Registered: 5-2009
Posted on Friday, 25 October, 2013 - 11:12 am:   Edit PostDelete PostView Post/Check IP

Don't feel bad about this: my 2005 Mercedes-Benz has crumbly insulation on the wiring going to the headlamps, which I learned about when changing a failed bulb.
I handle with care; I use a combination of heat shrink tubing and tape, electrical tape, and a product known as liquid electrical tape, to repair failed insulation best I can. So far, on my Car (1970 model) the insulation seems pretty good, even in the engine compartment. From photos I have seen online, my engine room is cleaner than most, thankfully.
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John Grieve
Experienced User
Username: john116

Post Number: 16
Registered: 4-2012
Posted on Friday, 25 October, 2013 - 01:50 pm:   Edit PostDelete PostView Post/Check IP

OK - thanks guys. I also thought of using that flexible ribbed conduit covering stuff as well on some of the wires, just as added protection. I know it's probably not Silver Shadow authorised, although have seen it on some engine bays of Spirits and it looked original....
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Jan Forrest
Grand Master
Username: got_one

Post Number: 516
Registered: 1-2008
Posted on Friday, 25 October, 2013 - 07:33 pm:   Edit PostDelete PostView Post/Check IP

I'm pretty sure that (almost) original spec cotton covered wiring in very close colour combinations can be obtained from specialist auto electrical suppliers. However the cost will be all but astronomical compared to modern plastic coated wiring. Fortunately much of the wiring is not inside the engine bay so that

a) the colour/material doesn't really matter much
b) it should be in much better condition and unlikely to need replacing.
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 660
Registered: 6-2009
Posted on Friday, 25 October, 2013 - 10:57 pm:   Edit PostDelete PostView Post/Check IP

Jan,

Unless they did some very early in the two-series production change, all the wiring in these cars is plastic coated. I have yet to find a single wire that doesn't have plastic insulation.

Brian
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Geoff Wootton
Grand Master
Username: dounraey

Post Number: 334
Registered: 5-2012
Posted on Friday, 25 October, 2013 - 11:07 pm:   Edit PostDelete PostView Post/Check IP

Hi Brian

Yet another SY-I / SY-II difference. My 74 SY-I uses a hybrid system of both plastic and cotton covered wires. The plastic covered wires have aged much better than the cotton ones. I suspect the very early SY-Is were all cotton.

Geoff
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Brian Vogel
Grand Master
Username: guyslp

Post Number: 661
Registered: 6-2009
Posted on Friday, 25 October, 2013 - 11:16 pm:   Edit PostDelete PostView Post/Check IP

Geoff,

I would have been surprised if the early SY cars didn't use fabric insulation on their wires and am utterly unsurprised that Crewe "went hybrid" as the years progressed.

I have been told, many times, that Crewe's general approach was to use what was on hand until it ran out, only then switching over to an updated alternative.

In this case, since the question was focused on a Silver Shadow II, I thought it pertinent to note that they didn't use any fabric-insulated wire (or at least I've never encountered any - if you ignore the woven fiberglass on the battery cable).

Brian

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