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nev
Thanks ~ nice to be here


Joined: 29 Apr 2006
Posts: 12
Location: Latrobe Valley Victoria

PostPosted: Sun Feb 04, 2007 12:31 am    Post subject: Positive earth Reply with quote

Are all morris's electrical systems Positive earth


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NZJLY
Free Wheeling


Joined: 14 Apr 2005
Posts: 103
Location: Hamilton, New Zealand

PostPosted: Sun Feb 04, 2007 6:30 am    Post subject: Reply with quote

No, most these days are negative earth, as a -ve earth means you can use a radio etc (as most car electricals seem to be -ve earth)

It is supposed to be quite easy to convert as well. Do you have a problem we can help with?

John


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Scouse
moderator


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

PostPosted: Sun Feb 04, 2007 9:27 am    Post subject: Re: Positive earth Reply with quote

nev wrote:
Are all morris's electrical systems Positive earth
Are you worried about the rest of the car if you change the battery to -ve earth ?

All Morris Minors (except very late UK builds) were +ve earth originally but the only item you're supposed to change around is the coil connections. Everything else fitted in the factory will be fine & there's even debate if the coil connections actually need to be swapped to.


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Padraic
I've got trainer wheels


Joined: 27 Nov 2006
Posts: 18
Location: Bangor NSW

PostPosted: Sun Feb 04, 2007 1:40 pm    Post subject: positive earth Reply with quote

Hi NZJLY

I got this off a morris site in the UK
I did it to my 55 morris and no problems


The procedure for changing over to negative earth is very simple. Most people do this when they want to fit a modern radio as these are polarity conscious.

1. Switch off ignition

2. Disconnect the battery and turn it round the other way. Cut two 'U' sections

from the metal bracket that retain the battery so it has adequate clearance from

the terminals.

3. Replace the two terminals on the battery leads (the positive and negative

terminals are different sizes). New ones are available from any good car shop.

4. Connect the earth connection to the battery negative terminal.

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.

6. Re-connect the dynamo.

7. Connect the positive lead to the battery.

8 Swap the 2 small wires on the coil over. These just pull off and slide back on. If

in doubt you should end up with the black and white wire connected to the

terminal marked - or neg.

9 If the red light on the dash goes out when the engine is running all is well. If not

repeat sections five onwards.

10 If you have one of the very early cars with an ammeter you will need to reverse this

as well or it will read backwards. Some of the very early cars have heaters that run in

reverse as well but only the VERY early cars do this. The windscreen wiper motor also

runs the opposite way but this has never proved a problem.


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Scouse
moderator


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

PostPosted: Sun Feb 04, 2007 5:03 pm    Post subject: Reply with quote

#2 & #10 aren't needed here.
The Australian cars had a battery bracket that went across the front, not the top so it's not a problem.
No Morris Minors were fitted with ammeters from the factory.


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