Re-wiring the engine bay

[p-B]

Because my 1966 S-type is now 48 years old, and the engine bay gets pretty darn hot.., I fear the wire's plastic insulation has been baked crispy hard.., and when the car is used again in earnest - it's likely to crack &/or generally become troublesome. So, I reasoned that while doing other jobs around the engine bay then I'd really ought to tidy things up and bring the wiring and connections up to a reliable standard.. In short I'd like to replace the wiring harness throughout the engine bay's, if not throughout the whole car !

However, being used to classic motorcycles, and paying about £40 - 70 ($65 - 115) for a full wiring harness of low volume classic Sunbeam S7 & S8's - I was a little shocked when quoted today for just an engine-bay harness ... with the whole loom costing over double that figure


I don't suppose anyone actually has a new / n.o.s. wiring loom (harness) for the small-saloon / for the engine bay please .. which they never got around to using ?
.. preferably one from an S-type RHD, but hey.. I'm sure that one from a LHD, from a Mk.II, or one of the compact Daimlers, or the 420 wouldn't be too far off ! ? (I am quite used to 'tailoring' wiring ..to actually fit motorcycles)

I have tried Autosparks and MES, Ken Jenjins and DMG., but I would be glad to hear of what other supplier you used, and the sort of cost.

Greatly appreciated, Peter

[Martec]

The MkII and nodoubt the 'S' type engine loom is quite large.

I don't know if you can find another new- old stock loom but its not difficult to make your own.

When rebuilding our MkII I tried to keep cost down by repairing and making as much as I could myself, that included the 5 looms.

As our car was scrap and took 8 years to rebuild I removed the looms (old clothe covered rubber insulation) worked out the wire loading and so the wire size to suit, then ordered enough wire in the correct colour codes and sizes plus the end fittings and took the lot back to sea with me.

A 20 foot washing line across my day cabin allowed the old loom to be hung along it and then follow it with the new wires. I couldn't obviously copy the braiding so used ther correct 'none sticky' loom tap (this allows it to be bent around corners) to bind the new looms together (the now old copper wire and insulation bends easier than the newer wire and is still excellent after at least 14 years.

Making your own loom allows you to add extras as well, uprated wire for the alternator and numerous 8 way fuse boxes and relays rather than the old two massive fuses.

Best of luck,

Brian

[p-B]

Thanks Brian,

Yes, I'd agree.. NOS is now unlikely but if I don't ask ...

I'm sure your washing line of wiring harness in the day cabin brought about one or two wise cracks Great use of your off watch hours though.

Autosparks S-type loom is now in 9 sections. I'm told that their quality and fit is good... but, their prices soon add up.

However imo - most automotive (car and motorcycle) wiring harnesses through to the 80's are pretty crude, and so yes it would be perfectly feasible to make my own.. The two things that are against this are the amount of time it takes to make a harness ...as a one off, and also the number of colours these looms use.

It's not something that I'd rule out ...not least because I would like to tailor it to modifications and fit (rather than the typical plastic wrapped sagging between hooks). You've got me thinking though..

I was wondering as I was driving today.., as to whether there was a better way of wrapping the wires ? I've used normal plastic wrap before, and spiral-wrap, and of course sleeves when there were no connections in the way of feeding the wires, but it may be that I can reuse most of the old wires (as long as the insulation hasn't gone hard) and so I'll need to cover it again with existing terminals (cleaned up but) still in place.

An easier alternative may an idea to cut & shove the existing harness, until I'm happy with the layout.. and then have sub-harnesses professionally made to order by the harness suppliers I've used before.

Thanks, Peter

[piman]

Hello Peter,

I think if you price up all the cable you need, the crimp ends,bits of sleeving, loom tape (proprietary cable tidys like spiral wrap just don't look very tidy in a car) then the difference between a ready made will not be that great.
However if you plan on fairly extensive additions it will be best to make your own. Loom tape is the best and is not too laborious to apply as long as you attach the two ends of the loom so as it is suspended as Brian outlined. Use some sticky insulation tape to fix junctions and tack long runs together neatly, makes for a tidier and tighter loom.

The alternative is to evaluate the ends of the loom and see if there is sufficient cable to cut back to good flexible insulation and re terminate? I don't know if that is practicable or not but worth checking?

Alec

[Martec]

Just to add to the above, we have the 1961 MkII that I replace the old cotton braided rubber insulation with new PVC insulated wire, then we have a heavily modified 1972 Marina, this is still on its original looms with just the occasional end cut back and remade and a new terminal (pvc insulation), unfortunately overlaid with modern wire and insulation for the EFI.

Then we have the modern 'S' type and we all know of its brittle insulation and broken wires, supposedly a bad batch or wire I was told, but our 2007 Focus is know to break the wire in the short loom to the Alternator!!

So from experience I prefer the older PVC insulated wire as per the MkII and Marina. As Alec says it takes time to order the correct colours and lengths for the loom. Two A4 pages at least, but there was a substantial saving and my time was free.

PS I was the chief engineer so not much was said about my washing line.

Brian

[blackbeltuk]

Hi all.
I ordered a new wiring loom for my S type. Having nearly spent 12k on my restoration.
I didn't want to take a chance with the loom. being 50 years old and have been patched
up here and there with different coloured wire. It turned up on Monday. 8 parts in all.
And I'm happy with the result. And for just over £700 I think it was worth every penny.
Now waiting for the weather to improve so I can crack on. And being that the car is completely
striped this shouldn't be to bad a job.
Ricky

[Martec]

Assuming your old looms in the sills are still in place, tie string to the ends before you gently pull it out so that you can tie the string to the new looms to pull them back into place.

I realised the problem in fitting the sill looms and inserted strings as I fitted the new inner and outer sills. Sensible really.

Best of luck with the job.

Brian

[blackbeltuk]

thanks for the tip brian. I'll bear that in mind when fitting the loom. As all my old wiring is still
in place
Ricky