Ignition coil wiring

[Pucketsport]

Can someone tell me which wire from the wiring diagram corresponds to positive and negative on the coil ? The wiring diagram has C.B and S.W ?
By the way my car is standard with positive earth.

[philthehill]

With a positive earth system....................CB is positive (+) and SW is negative (-).

With a positive earth system - current actually flows in the reverse to what you would consider at first sight i.e. the chassis via the positive terminal is live and the circuit connection is made when the appropriate switch/connection is operated/made so allowing the circuit/current back to the battery negative earth.

[Pucketsport]

Thanks Phil , still trying to get my head around the effects of a Positive earth, that helps a lot.

[philthehill]

http://mgaguru.com/mgtech/electric/et098.htm

There is also a large amount of information relating to body corrosion (or not- opinion seems to be somewhat equally split) with the use of positive earth systems and the need to change to negative earth for modern day electrical components available on the web.
Unfortunately too many links to post on here.
Phil

[Pucketsport]

Yes I heard there were benefits of reduced body corrosion with +ve earth. I just want to keep my car as standard as possible.

[firedrake1942]

Given the state of many of our cars before we took them in hand, it would be good to define 'reduced' in terms of body corrosion. That said some of the older cars do seem to have survived better.

[philthehill]

As I said in my post above there is plenty of technical information on the web but whether you would be able to 'define reduced in terms of body corrosion' is another matter.

[myoldjalopy]

In the end, it is more about how well the car has been looked after and maintained over the years. The reason most Minors that were produced are no more is due to the absence of this care and attention rather than whether it is +ive or -ive earth

[Pucketsport]

Agree its down to the owners care. I was extremely lucky with my 57. It had one owner in Adelaide for 50 years before changing hands a few times and the body was in amazing condition with no structural rust and some very minor cosmetic rust which was easily repaired.