New wiring harness for Javelin

[paul wilks]

I am considering having my Javelin "re-wired".

Can someone tell me (being no mechanic/auto electrician!) whether replacing the wiring harness with a new one (say from JCS) is a straightforward job for a qualified auto electrician?

Would there be any benefits in changing to an alternator and what are they, please?

What extra work would be involved other than changing polarity at the "battery end"? And which type of alternator would members suggest.

Guidance in a step by step format which I could pass on to a non- Jowett auto elctrician would be really helpful and gratefully received!
1) retaining present dynamo and polarity
2) changing to alternator and polarity

Thanks as ever.

Paul

[Chris Spencer]

Paul - I will let Keith advise on the alternator vs dynamo & neg earth issues - However, I would advise that you need a auto electrician that understands classic cars - further to this you can probably save yourself some money - the harness travels from from front to rear up through the O/S/F 'A' post / windscreen pillar and across the roof rail and onwards to the rear inner wing - it means that you need to remove the head-lining - if you can do this yourself and then refit it - you are going to save yourself several hours labour / auto electrician time / money.

[Keith Clements]

A search for alternator on jowett.org, (you can do this yourself of course), reveals http://jowett.org/jowettnet/dt/tech/mod ... rnator.htm.

And http://jowett.org/jowettnet/dt/tech/mods/JUp4alt.htm

Although Haynes type manuals have their value, basic skills and experience are needed to do a harness replacement. A modern auto-electrician may not have them along with sympathy, patience and thought. When we get around to doing Peter's car, we will record the process which might help. So you may have to wait until then. If you go to the Gallery you will see TOPIC some of the pictures used to record the state of the harness when we stripped the car. This will give you some idea of the things your tame sparks will have to contend with. The rear harness through the headlining is TOPIC here. Do not be fooled into thinking this is OK because you cannot see it!

Obviously you need to know the wire colour coding system, be able to identify all the electrical components and their terminals and check everything as you go.

My wire list, constructed during the SC rebuild, is a logical way to do it. Basically it starts from the battery and works down each branch to all the components. Note that this list is much more complex than you would need as it has many more fuses and relays. The logical schematic that this wiring tracer relates to is here. A more familiar physical position schematic is here (not all modifications have been added to this).

Another way is to do each harness in turn, but that does not allow you to test each component as you do it. Note the testing is done wih a multimeter, at first, before connecting the battery once all wires are in place. I have a harness wiring list from Drummond, but am busy at the moment so cannot find the link on Jowett.net.

You will probably find that most of the electrical components will also need renewing e.g. bulb holders, brake switch. Doing so will make the job a lot easier.

This may seem daunting, but the alternative is an unreliable car and a fire hazard. As Chris says, the more you do yourself, the cheaper it will be, and probably better, as you can bounce questions through JowettTalk.

[Jack]

Having done a lot of the SC electrics, the wiring involved in 1950s engineering is not very complicated.

If you've got a wiring diagram with all the colours shown, and the harness you are fitting matches all these colours (it should) then it is a time consuming but not particularly complicated job. It might take a week of evenings to do, or a full weekend.

To pay an auto electrician would be a lot of money, because I can imagine it would take them quite a few hours to do, but they wouldn't be doing skilled work, they'd just be doing the same thing you'd do on the car. Doing it yourself isn't complex once the harness is physically in place, particularly if the other components on the car are all known working and don't need to be removed and replaced (though some will so that you can remove the existing and attach the new connectors)

The other significant advantage to doing it yourself is that you will be in a good position to solve any electrical problems in the future - having done the SC it is now easy for me to understand the little things like why the horn keeps going off or why the lights behind the gauges aren't working etc.

Jack.

[paul wilks]

Thanks for the advice. Don't think I'll be doing it for a while!


Paul

[Drummond Black]

Paul,

As Keith says, he did receive a lot of wiring data from myself relating to Javelin / Jupiter rewiring.
It consisted of :- Harness pictures on pinboard
Wiring Diagram ( Includes Alternator wiring, Extra Fuses, Relays, Flashers plus many other extras )
Wiring Schedules ( 14 sheets of it )

If you wish copies please just let me know.

DRummond

[paul wilks]

Thanks for the offer Drummond. I'll hold fire on this for the time being. Another job to be done at some stage!

Thanks again

Paul