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Re: Postive to negative earth

Posted: Sun Mar 30, 2014 10:33 pm
by bmcecosse
My alternator works perfectly well with the Ign light wire disconnected - I agree it's better to be connected - especially if you don't have an ammeter - but it's not always necessary. And yes - the coil wires must be swapped round when changing polarity, to get the best spark.

Re: Postive to negative earth

Posted: Mon Mar 31, 2014 8:53 pm
by vibrodolly
Hello,

Thanks for that. I found the issue - the LT lead had come off the distributor. It now runs BUT...
The fuel pump has stopped working. It's not a SU pump, but another after market variety of unknown origin/ make.
I don't know if I can get into it to clean points.

I could put a SU pump on, but the fuel line from tank to pump has had the nut cut off the end and a hose attached with clips.
Unfortunately an SU pump might mean a new fuel line.

Any other ideas or have I missed changing something over on the pump?
Thanks

Nick

Re: Postive to negative earth

Posted: Mon Mar 31, 2014 9:21 pm
by mogbob
Nick
Identifying what fuel pump you have got.... will assist in the problem solving.Any chance of a photo for the Forum spotters to identify ?
Use a small hand mirror to see if there is a name or code number / anything stamped on the unseen side.
Otherwise after disconnecting the battery, unbolt the pump from the bulkhead and examine.A bit of degreasant and an old toothbrush, might be needed if it's really filthy !
Armed with the right information, a diagram and a possible source of new points ( if necessary ) can be tracked down.It may be a simple case of cleaning the points or a blocked filter.
Bob

Re: Postive to negative earth

Posted: Mon Mar 31, 2014 9:32 pm
by vibrodolly
Will need to look again in the light, but pretty sure it's this one http://www.ebay.co.uk/itm/Morris-Minor- ... 3cdcc82676
fitted to my minor

Thanks
Nick

Re: Postive to negative earth

Posted: Mon Mar 31, 2014 9:38 pm
by alexmcguffie
Before trying to strip it down check that there is 12v getting to the white wire that feeds the pump. It's not fused and comes from the bottom left hand side of the fuse box. Given that you've been doing wiring mods, there's a good chance.....

Re: Postive to negative earth

Posted: Mon Mar 31, 2014 10:14 pm
by bmcecosse
The ebay pump you show is 'electronic' - and therefore will be polarity sensitive. Did you change polarity when fitting the alternator? If so - that's why the pump doesn't work.....

Re: Postive to negative earth

Posted: Sun Apr 06, 2014 4:30 pm
by vibrodolly
Hello and thank you for your directions again.

Alternator fitted and fettled. Connected correctly. Old wires disconnected.

Fuel pump was a +ve -ve problem. Has been swapped over and all ok now.

The small lead from the new alternator that should go to the ignition light does indeed "kick" the alternator into charging. I tested this with a multimeter. I touched the this lead onto the + of the battery... you have to do this every time. Is it ok temporarily to leave a permanent connection from this lead to the + battery terminal?

My only issue now is where is an easy connection to the ignition light for that lead?

Thanks

Nick

Re: Postive to negative earth

Posted: Sun Apr 06, 2014 10:08 pm
by bmcecosse
Don't connect that wire 'permanently' - and yes - some of the newer alternators need that connection - the older Lucas ACR 15/16/17/18 don't. The original wire from the IGN light is present on the old Regulator - it is the small wire connected to the D terminal. Use that to excite the alternator.

Re: Postive to negative earth

Posted: Mon Apr 07, 2014 5:23 pm
by andy.pointeer
I agree with bmcecosse you need to connect the small lead from the alternator to the brown/yellow wire to the IGN light that was on terminal D. this can be seen in the second picture in my last post above.

Re: Postive to negative earth

Posted: Mon Apr 07, 2014 5:55 pm
by bmcecosse
Thanks Andy - I wasn't sure about the colour of the wire.

Re: Postive to negative earth

Posted: Wed Apr 09, 2014 4:43 pm
by vibrodolly
Thank you
Absolutely right - now working well.
Advice - don't leave the small brown wire connected to the battery - you end up with a flat battery.

Thanks

Nick

Re: Postive to negative earth

Posted: Fri Apr 11, 2014 10:34 am
by vibrodolly
I have a couple of extra questions about the conversion I have just done..

I understand how lights do not need connections swapping over as with a bulb, it doesn't matter what was the current flows, the coil swapping makes sense to get the spark flowing the correct direction, but how come motors do not need connections swapping? Surely the starter motor would go the other way as, having swapped the direction of current = motor moving opposite direction on a DC motor?

Just a thought

Thanks

Nick

Re: Postive to negative earth

Posted: Fri Apr 11, 2014 12:56 pm
by bmcecosse
No - because both the field windings and the commutator current flows have been reversed - the motor runs same direction. There are some who have reported heater motors running opposite direction... This could be the case if the motor has a 'permanent magnet' field - but I have not come across one........

Re: Postive to negative earth

Posted: Fri Apr 11, 2014 1:19 pm
by vibrodolly
Thank you

The car seems to run better now as well, though that may be my imagination.....