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negative earth rewire!

Posted: Wed May 26, 2010 7:11 pm
by 1mustard
Hi all, i am currently restoring my 66 traveller, need some correct advice, i am going to fit an alternater, and want to wire the car negative earth, so what do i need to change? fuel pump?, any wiring?, starter? i was going to buy a fitting kit for the alt conversion which includes a loom so that should be straight forward enough. Any advice would be appreciated, i am trying to keep my ever spiralling costs down!!!
Thanks
Andy

Re: negative earth rewire!

Posted: Wed May 26, 2010 7:14 pm
by PSL184
Neg earth instructions here: http://www.mmoc.org.uk/index.php?page=322

Alternator wiring below...

[frame]Image[/frame]

Re: negative earth rewire!

Posted: Wed May 26, 2010 8:12 pm
by bmcecosse
Swap the coil connections and clean the points and the fuel pump points. Nothing 'new ' required. And - an alternator from a scrappy will be fine - I only ever pay £1. And you don't need a 'harness' the wiring swap is simple.

Re: negative earth rewire!

Posted: Wed May 26, 2010 9:48 pm
by monty55
I was just about to do the same.
I have a '55 convertible with a cylindrical heater - do I have to change the connections to this, or only older cars than mine?
Thanks
paul

Re: negative earth rewire!

Posted: Wed May 26, 2010 9:52 pm
by bmcecosse
Pretty sure we thrashed this out recently - the heater fan does NOT run the other way when you reverse the polarity!

Re: negative earth rewire!

Posted: Wed May 26, 2010 11:06 pm
by monty55
Great - saves me a job :D

Re: negative earth rewire!

Posted: Wed May 26, 2010 11:33 pm
by bmcecosse
But - if you DO find it sucking the heat out of the car - do post up - it will save Polo2k a LOT of work with his Air Con project! :roll:

Re: negative earth rewire!

Posted: Thu May 27, 2010 7:15 am
by alex_holden
monty55 wrote:I have a '55 convertible with a cylindrical heater - do I have to change the connections to this, or only older cars than mine?
Yours should be fine, it's the later rectangular heaters that are polarity sensitive (at least the two I've worked on were).

Re: negative earth rewire!

Posted: Thu May 27, 2010 10:04 am
by polo2k
bmcecosse wrote:But - if you DO find it sucking the heat out of the car - do post up - it will save Polo2k a LOT of work with his Air Con project! :roll:
Ha ha that would indeed suck! :P :lol:

Re: negative earth rewire!

Posted: Thu May 27, 2010 11:09 am
by bmcecosse
Alex - 'we' determined that they are not polarity sensitive........

Re: negative earth rewire!

Posted: Thu May 27, 2010 11:19 am
by alex_holden
bmcecosse wrote:Alex - 'we' determined that they are not polarity sensitive........
The way I remember it I posted a photo of the motor label that proves mine is! :D

Re: negative earth rewire!

Posted: Fri Jun 11, 2010 7:19 pm
by 1mustard
Thanks for the advice, i went to the breakers i managed to get one from a old mini (a series are rare in breakers nowadays!), it cost me a bit more than a £1 though, cost me £20, i dont think i could find a breakers where i could get a wheel nut for a £1 in essex! still cheap at £20!, one more question about mounting, my engine had a dynamo, which is obviously longer than an alternater, i thought this may happen so i took the mountings etc, of the engine in the breakers for my engine, however the mounting holes, are much further back, can i get another mount anywhere or should i just use a longer bolt?, i think it would be to unsturdy personally, whats the usual fix?
cheers

Re: negative earth rewire!

Posted: Fri Jun 11, 2010 8:27 pm
by charlie_morris_minor
when i did my first conversion i used a long bolt, however you can get the correct bracket which were used on minis when they first started to fit alternators, they look like this..

http://cgi.ebay.co.uk/DYNAMO-ALTERNATOR ... _825wt_911

I would do a search of mini suppliers on the web as they seem pricey when you include p&p..

Re: negative earth rewire!

Posted: Fri Jun 11, 2010 8:53 pm
by bmcecosse
Will it not fit with the Mini bracketry? On later engines - unfortunately they moved the mounting holes forward on the block casting - early alternators had a longer bracket. Use a long bolt meantime - but it's not ideal - so search out an early bracket. Make SURE the alternator pulley lines up correctly with the water pump and the crank pulley.

Re: negative earth rewire!

Posted: Sat Jun 12, 2010 3:59 pm
by katy
It shouldn't be too hard to fabricate a bracket. (from the looks of the one at the link posted)

Re: negative earth rewire!

Posted: Sat Jun 12, 2010 7:15 pm
by eric seber
HI is it possible to reverse pos to neg earth on electronic SU pumps

Re: negative earth rewire!

Posted: Sat Jun 12, 2010 8:52 pm
by bmcecosse
Don't think so - they seem to be sold for specific earth arrangement - but you could ask the supplier - there may be an internal switch. The general opinion on here is that electronic SU pumps are to be avoided like the plague! Far more reliable with a good old pump fitted with new points.

Re: negative earth rewire!

Posted: Sun Jun 13, 2010 2:44 pm
by 1mustard
no worries i have sussed it, i just looked on the bull motif website and they sell them for £8!, bit pricey but that'll do and yes the pulleys line up no probs, cheers all.

Re: negative earth rewire!

Posted: Sun Jun 13, 2010 2:53 pm
by 1mustard
no worries sussed it, i looked on the bull motif website and you can buy them for £8!, bit pricey but it will do, lucky its so easy to get bits and pieces for minors, I am in no hurry i have got to finish the paint work and rebuild it first anyway!
cheers all.

Re: negative earth rewire!

Posted: Sun Jun 13, 2010 10:18 pm
by billlobban
eric seber wrote:HI is it possible to reverse pos to neg earth on electronic SU pumps
Dont know about the electrickery versions but modern SU points type fuel pumps are dual polarity