Classic cars forum & vehicle restoration.

[chimpchoker]

Hi folks,

Pulled some of the wiring loom out of the jag earlier and got to thinking about replacing it later in the restoration. Because I am doing the vast majority of the job myself I was wondering how people would tackle a re wire job. Where do you get the right wires from, indeed how do you decide on the right ampage, colours and even lengths etc.

How do you add in extra wiring for say the +Pos earth to the -negative earth conversion and also the likes of extra wire for auxillary items like hi fi's. I'm not going down the actual restoration route rather upgrading as I go so a cloth covered loom, to me is not essential. Also do you do the rewire item by item say each individual wire to the headpamps, check the connections then tape the wires up together into a loom or do you make the loom then fit it to the car ?


Actually the wiring will be a long way off but it's been bugging me a bit this week.

Take care,
Alan

[buzzy bee]

Hi

some auto electricians places may have made looms for your vehicle type before and then it should be pretty close to fitting your car, if not I think they can sometimes make you one up, from your old loom. I am non to hot on Electrics, but I made a simple loom for my Ford, yet to fit, and I found that quite interesting but it was time consuming! Other than that I would wait for some other oppinions, UKDave seems quite good at electrics.

Cheers

Dave

P.S... I know the feeling when something bugs you, even if it is miles off, my roof is the same the vynl patch, but I want it mot'd first, so keep trying to put it out of my mind, but it keeps creeping back in!

[UKdave2002]

Hi Alan

As a starter here is a couple of firms who will be able to supply you with everything you need wiring wise.

http://www.autoelectricsupplies.co.uk/
http://www.vehicle-wiring-products.eu/VWP-onlinestore/home/homepage.php

In their online online catalogues you will find a lot of info regarding wiring size and if you go into the resources link on the auto electrical supplies you will fine a wiring colour code chart for British cars.

Regarding how to start, there are many ways, if you are replacing a whole section of a loom, its best to get it out , fix it to a board, put some nails in the board to mark key points, and then write the detail on the board, remove the old loom and now you have a template, to which you can add other cable if required.

If you don’t have an old bit of loom I have used a bit of rope to act as a dummy loom, found the correct route and then tied tags to mark where wires come out and what length they need to be, then make a board up as above and build the loom up.

You can get from either of the above suppliers proper harness tape which will look the part and modern wire with cloth braid in all the right colours (not sure if your Jag has PVC or braided insulation) You can still get PVC wires from the above, but not in all colours anymore, it is being replaced by thinwall cable which is available in all colours but as the name suggests is a thinner cable and if you use the correct rating can look a bit out of place in an old car. I had this problem recently on the Stag so just ordered the next size up, which could carry over double the amount of current compared to the cable I needed ! but it looked right!.

One other thing you need to consider is crimped connectors, classic cars use “uninsulated “connecters with plastic sleeves. Unfortunately IMHO you see loads of cars with the “Insulated” connectors like in the cheap kits you see in Halfords. They never look right to me in their bright red, yellow & blue colours, but worse than that, folk don t use them correctly. As with all crimped connectors you have to use the right size for the wire, but the insulated ones must be crimped twice, once on the copper wire and once on the cable insulation, if you don’t crimp the insulation the connection will be unreliable.
If you are going to do a bit of wiring I would invest in a tool that can crimp the uninslated connectors, it looks correct and you can see if its crimped correctly. You will also need a tool for the bullet connectors or need to buy the solder bullet connectors.

I know electrics put a lot of people off, but think of it like this, its just a load of very simple things which when bundled together look complicated! Approach it 1 step at a time and you find it is straight forward.

Dave

[Rick]

Chimp, although not specific to the wiring part of a rebuild, I find it helps a lot to photograph everything as it is removed (but I guess you're probably doing that anyway!), it makes replacing stuff or putting something back together, a whole lot easier

Rick
_________________
Rick - Admin
Home:https://www.oldclassiccar.co.uk
Videos:https://www.youtube.com/user/oldclassiccarRJ/videos
OCC & classic car merchandise (Austin, Ford ++):
https://www.redbubble.com/people/OldClassicCar/shop

[buzzy bee]

Hi

Not sure this was strictly allowed, but I got through college doing this. In all of my practical exams, I would take a few pictures, and hey presto I know how it goes back together. I also did a few other things that I perhaps regret doing now, but that is another story!

Cheers

Dave

[chimpchoker]

Thanks for the tips so far.
It's going to be a full rewire jobby. All new wire, connectors, fuses the whole shebang. After all what is currently there is 40 years old in january !!. I think of it like this, I'm 46 and i'm broken and knackered and need replacing but the wife is a skinflint and won't trade me in thankfully so a 40 yr old wiring loom could be the same.

If I'm spending all this money on the restoration then I'll be buggered if I'm going to risk an electrical fire by skimping on a wire loom.

I would like to do it all myself and I want to use relays for as much as I can, also convert it to neg earth and eventually fit the "boys toys" such as a lairy hi fi, sat nav, modern lights et al.

Thanks for the websites, I'll check them out soon and print them for reference.

I was going to solder all connections and use heat shrink over joints prior to the final wrap. Currently it is braided cloth but I'm not into the original is best if I can get a better job using modern wrap.

The board idea sounds really well and there is space on the garage wall to do this.

One question though and it is how do you fit in more options into the wire loom. For example, if I wanted another live feed from the battery to run say an amp or to run the cigar ( it is a jag after all) lighter both of wich were not in the original car, how do you incorporate these in the hard wiring of the loom? On the face of it I would think that it is another piece of wire from the battery terminal down through the car to the amp via a fuse block and or a relay to the amp but that sounds too easy and may well end up with a lot of wires off the terminal.

Also would it be ok to run a large capacity main wire from the terminal throughout the car then "splice" into this other wires. The thinking being that each "spliced" wire would then only take the individual current. The important thing being the load on the master cable with everything switched on.

Finally, I'm up to 1239 in the photo count Rick, Now you know why it takes 3 hours to remove a radiator, lol.

[pigtin]

'When I were a lad' I had to use the board and nail method to create harnesses as part of my training I believe that it is still the best way.

In common with many people like myself, my car electrics are a disgrace; I tend to run any extra power cables from the battery via a cheap line fuse and ty-wrap the wires to the old harness. But then, the wiring on 30s cars is pretty basic-for example: it took just over half a day to wire the 10/4 from scratch. Whereas a post war Jag would be a pretty daunting prospect. As UKD says using a heavier wire is always the safer option and the 'crap' insulated connectors that you 'pinch' to the wire; (rather than crimp, both cable and insulation) are to be avoided at all costs.
The only wiring failures I have had over the last few years have been down to this sort of connector.

Don.

[UKdave2002]