polarity change

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mr.bird
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polarity change

Postby mr.bird » Tue Sep 05, 2017 10:50 pm

hello all,has any one done the polarity change themselves,there seems to be much disagreement on the subject'

palacebear
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Re: polarity change

Postby palacebear » Tue Sep 05, 2017 11:33 pm

Straightforward polarity change should be easy enough as long as you aren't making any other changes. However, I can see little value in changing polarity for the sake of it. If you intend fitting accessories such as a cd player that demand negative earth then its a neccessity, as it will be if you convert to alternator charging in place of dynamo.

It used to be said that positive earth cars corrode faster than negative earth but I don't think there's much evidence to support that claim!
1956 4-door called Max

StillGotMy1stCar
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Re: polarity change

Postby StillGotMy1stCar » Wed Sep 06, 2017 10:31 am

First check that it has points ignition as it will fry an electronic one. The same with the fuel pump, check it has points and no small black cylindrical device with red and black wires if it has just reverse the connections, will most likely have nothing or a capacitor which can be connected either way. You will also need to change the battery terminals as the pos and neg are different sizes.
Disconnect the battery turn it round, just connect the neg terminal (the new earth), pull the small F wire off the dynamo and with a new length of wire connected to the F terminal of the dynamo flash it to the empty pos terminal of the battery a couple of times, don't hold it on for more than a couple seconds. This has your dynamo repolarised and you can reconnect the original wire back to the F terminal.
The next thing needed is the reversal of the coil terminals.
Job done.
I only changed my earth so I could fit a newer radio.
Regards John.

geoberni
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Re: polarity change

Postby geoberni » Wed Sep 06, 2017 4:36 pm

If in any doubt there are videos on the subject on youtube.
Basil the 1955 series II

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SteveClem
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Re: polarity change

Postby SteveClem » Wed Sep 06, 2017 6:45 pm

Took me 15 minutes on a bog standard car, following instructions. If I can do it anyone can.

StillGotMy1stCar
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Re: polarity change

Postby StillGotMy1stCar » Wed Sep 06, 2017 6:58 pm

I have to admit I didn't bother changing the battery terminals, they aren't the best fit though.
Regards John.


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