David,
First off... why would you ever want to convert a negative earth to postive?
The rest of the LBC world wants to go the other way (ie.. positive earth to
negative)
Secondly, what year Spitfire. I'm not sure if any of the Spitfires were
positive earth. And if you're working with an later car (1975 on) there are
too many electical components that must stay negative earth.
If you have a generator equipped car and want to convert from Positive earth
to negative.... (from the Moss catalog)
*** if you have an original positive ground radio you will need to remove it
or find one of the "converter" kits. Since the radio is polarity sensitive
and typically grounded to the body you must be careful or it'll fry.****
1) disconnect the battery
2) reverse the two leads to the coil
3) remove the two leads to the generator
4) connect the battery with the negative terminal connected to ground
5) take a piece of 14 guage wire and connect it to the main "hot" terminal
of your starter or a "hot" terminal on the fuse block.
6) flash (lightly touch) the wire to the field (smaller) terminal of the
generator. You will see sparks when you do this. Don't connect the wire!
one touch is enough.
7) remove the 14 guage wire and reconnect the generator leads.
8) If you have an ammeter or voltmeter installed the leads will need to be
changed.
if you have an electric fuel pump fitted it may need to have the leads
reversed also.
Fan, starter and wiper motors don't "care" about the polarity.
If in doubt, find someone experienced to help. It's very easy to let the
smoke out of the electical system... and not much fun fitting a new harness
when you burn it!
Jim
> -----Original Message-----
> From: David Stevely [SMTP:DStevely@webleicester.co.uk]
> Sent: Friday, July 31, 1998 11:18 AM
> To: Spitfires
> Subject: Posative / Negative earth ?
>
> Question for you all
>
> I have been informed that it is possible to change my negative earth
> spitfire to posative merely by, and I quote 'arcing out the coil low
> tension circuit'.
>
> Is it possible that this would work, my friend tells me he has changed
> the polarity on his spitfire several times, but t
> hat it is only possible on models produced around the mid 60's.
>
> Can anyone tell me if this is true and describe the actual method of
> conversion any more scientifically.
>
> Thanks
>
> Dave.
|