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Positive - to - Negative earth

Posted: Sun Oct 29, 2006 10:34 am
by sidsmith
Hi all you moggy men, I have a 1956 splitscreen Moggy that is POSITIVE EARTH, so I changed it to NEGATIVE EARTH as per technical Tips CD,
ie changed the battery round, re memorised the dynamo with a piece of wire, and changed the leads over on the coil.Although the engine turns over and the ignition light is on the car won't start. So I asked a chap on the M M stand at the classic show ( NEC ) and he said that I have to do something to the distributor as well to complete the change over, Could someone out there enlighten me as what to do in an EASILY DESCRIBED way as I'm not up on electrics very well. Your comments would be most welcome.
Cheers Mungo.

Posted: Sun Oct 29, 2006 12:54 pm
by aupickup
nothing has to done with the distributer.
it would appear that you have done everthing correct
do you get a spark at the spark plugs.

Posted: Sun Oct 29, 2006 1:28 pm
by bigginger
...and have you swapped the wires round at the coil?

Posted: Sun Oct 29, 2006 1:32 pm
by aupickup
well he did say that,

Posted: Sun Oct 29, 2006 3:10 pm
by bigginger
:oops: Missed that... :oops: :lol:

Posted: Sun Oct 29, 2006 4:32 pm
by bmcecosse
In fact - the points should be renewed - they will have developed a pit and a peak, and with the voltage reversed this too reverses. Could just stone/file them flat - but new points and condenser would be wise. However - this doesn't happen immediately and it should not be stopping the car from running. Check where you swopped the wires at the coil - are either of them loose/broken wire that sort of thing ?

positive to negative earth

Posted: Sun Oct 29, 2006 6:37 pm
by sidsmith
Hi all, thanks for your input, i think I have sussed it now. I have just checked it all over again and made sure the positive + lead from the coil is going to the distributor, the car starts first time . I don't think I will have to change the points as i put new ones in as well as new plugs a couple of months ago, so now I can hopefully fit my Temp' gauge and radio.
many thanks ....Mungo :)

Posted: Mon Oct 30, 2006 11:00 am
by Alec
Hello SS,

with your car now negative earth the coil -ve shoud be connected to the distributor (white\black cable) and the live feed (white cable) should connect to the +ve coil terminal. It should run if the polarity is incorrect but the spark will be weaker.

Alec