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chopper
Got the keys


Joined: 24 Jul 2004
Posts: 40
Location: Brisbane - southside

PostPosted: Tue Jun 14, 2005 8:30 pm    Post subject: + or - earth Reply with quote

Is it easy to swap the wiring over to a - earth or just leave it as a + earth. Apart from turning the battery around what else needs to be connected differently?

Thanks
Chopper
Red Ute


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MorryStu
valued contributor


Joined: 02 Jan 2005
Posts: 260
Location: Grafton, NSW North Coast

PostPosted: Tue Jun 14, 2005 9:52 pm    Post subject: Reply with quote

Generator will need to be changed to an Alternator, and if you get the right one you wont need a regulator. Every thing else will be fine, except the fuel gauge, in mine it is back to front...


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Scouse
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Joined: 15 Sep 2003
Posts: 5266
Location: Wollondilly, NSW

PostPosted: Wed Jun 15, 2005 8:31 am    Post subject: Reply with quote

The generator can be repolarised to -ve earth if you wish to keep it. An alternator is preferable IMHO anyway.
There is a procedure somewhere..............<goes off to look>.


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chopper
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Joined: 24 Jul 2004
Posts: 40
Location: Brisbane - southside

PostPosted: Wed Jun 15, 2005 12:11 pm    Post subject: Reply with quote

thanks, I might go for the alternator what is a good one to get? It is for a 948 engine.

chopper


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Scouse
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Location: Wollondilly, NSW

PostPosted: Wed Jun 15, 2005 12:15 pm    Post subject: Reply with quote

Get the alternator & rear bracket off a lateish Mini (mid '70s or so).
The one to go for is the type with the inbuilt regulator (no external reg to worry about Very Happy ).


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stephen
I'm new - be gentle


Joined: 07 Jun 2005
Posts: 5
Location: Brisvegas

PostPosted: Thu Jun 16, 2005 4:24 pm    Post subject: Reply with quote

Or you could try this:

http://www.mmoc.org.uk/technicaltips/Negative_Earth.html


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rustbucket
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Joined: 20 Apr 2004
Posts: 646
Location: Sydney

PostPosted: Fri Jun 17, 2005 4:36 pm    Post subject: Reply with quote

The generator is fine as it is,the earth is the earth on it whether neg or positve....
its the regulator that is changed.You must actually short out one of the shunts on the regulator a few times and that will convert it to neg earth.I have done this and it worked...which one it is I cant remember alternatively it can be shorted at one of the terminals ,that i cant remember which one,all this is done after you have reversed the wires on the coil and the battery.
There is another way that a few use to try and it worked for them
they simply reversed battery and coil and that was it,they drove it and it was fine,they didnt even short out the regulator it just did it itself...go figure...but I saw them do it.But an auto electrician charges little to do it as it such a simple procedure.Go see one if unsure they can do it on the spot,youll wonder why its so easy when you see em do it.
but what you have all forgotten is the coil must have the wires changed around this is the most important thing,you can always tell what polarity a car is by the coil wires.Very simple when the coil has neg and pos on it,the older has SW and I forgot the other, always forget which is which but i think they refer to where the wire goes to.
Example if the positive wire goes to the dizzy then the car is negative earth,
I cant remember the fuel guage being a problem when converted
as earth is earth whether pos or neg,if i remember rightly the 2 terminals are the same power only interupted by the guage thus the body is the earth and that doesnt matter if neg or posive as long as its oposite to the power in the wires.I remember them being fine and Ive had and converted a lot to negative earth.Try your earth at the fuel tank im sure youll find its something else doing it,ive usually been able to fix those and usually the earth or more likely a wire shorting.
Radios are polarised ,and it matters that the polarity of car and radio is matching unless you isolate the radio from the cars body....but the aerial will short it out if not isolated.




Last edited by rustbucket on Fri Jun 17, 2005 4:53 pm; edited 1 time in total
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Scouse
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Joined: 15 Sep 2003
Posts: 5266
Location: Wollondilly, NSW

PostPosted: Fri Jun 17, 2005 4:44 pm    Post subject: Reply with quote

Shorting the shunt in the reg is actually the easy way of doing step 5:
5. Disconnect both dynamo leads and use a long length of wire to connect the small dynamo terminal to the battery positive for five to ten seconds. This removes any magnetic memory that the dynamo has so it charges the correct way.
Quote:
There is another way that a few use to try and it workred for them
they simply reversed battery and coil and that was it,they drove it and it was fine,they didnt even short out the regulator it just did it itself...go figure...but I saw them do it.
I've seen/done that too. The ignition light flares alarmingly bright for a couple of seconds then goes out & the system is converted to neg earth Very Happy .
I'd advise the proper method though as described in the link, just to be sure.


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