Dear All,
I am a new member to JCNA. This is my first time on the forum. I am the owner of a 3.8 1965 S-Type Auto LHD Saloon I picked the car up in January of this year from Florida. It is a one owner original numbers car, the car has a claimed 68,500 original miles. On first site it looked fine, but as I went around the car it appeared that a restoration had been started and then had abruptly stopped. The guy who was showing me the car was rather reluctant to advise much detail (He was maintaining the car for the lady owner who was 85 and suffering with Alzheimer's.) I was hesitant to buy the car because of the different things I had found wrong, but my gut instinct was telling me that this could be a great project car. A long story short, I negotiated with the son who was selling the car on behalf of his mother(he lives on the west coast) I never did meet him only the individual who had serviced the car. When the car arrived in Houston I started on the interior it quickly became clear that most of what had been done was cosmetic and poorly done at that. I have redone the whole of the interior (At this point I must point out at no time did I consider rebuilding to concurs standard) All I want is a nice looking, unique,reliable, safe, part time driving car. I thought I was ready to have the car inspected and registered but at the 11th hour I have come across a problem that I am having trouble with and was hoping that someone on the forum may be able to offer some advise. I need to change the car from Positive Earth to Negative Earth Dynamo/Generator is not charging battery. I have followed the instructions I have found on the internet but have two specific issues. One is the car has electronic ignition and I have no Idea how to change this, at the same time I have a electronic fuel pump the instruction's I printed off indicate that I need to swap the Black Negative wire to the Positive and the Positive wire to the Negative is this correct? The other issue is the Dynamo itself it indicates after switching the battery terminals and before starting the car I need to polarize the Dynamo/Generator, I have tried to do this as instructed but have not seen a spark as the instructions indicate (By thew way I did switched the leads on the Amp Meter as advised. Has anyone else had the same problems and if so could you please advise how to resolve them I cannot get the car insured or inspected or registered until this issue is resolved any assistance would be most appreciated

Submitted by petepratt@gmail.com on Sun, 10/10/2010 - 13:30

Guys,
sorry for the delay in responding but I was away from my computer all day yesterday.
Thanks for the information it is most appreciated. I am about to change the pump wiring system today (Sunday) I will keep you informed.
As for the clock, I had sent it away for repair earlier in the year. So I e-mailed the company earlier in the week, they responded immediately and advised that just over a year ago and because of other people doing the same thing, they included in their fix the ability to run the clock in either positive or negative earth mode.

Best regards,

Peter Pratt

Submitted by woebegone@mind… on Fri, 10/08/2010 - 13:26

Depends on the pump.
If points style (later) reverse the electronic bit (diode or cap, depending on vintage) and it will work fine.
The fully electronic one will require insulating/isolating if one wire (and cannot recall whether it's a one or two wire unit) or reversing wires if two-wire (what was grounded now becomes power in, what was power in is now grounded).
Later points units were ambidextrous.
Clock still work?

If polarity is not set on generator, it will NOT charge, rather show a discharge when charging.
Polarize and that should fix it.

Submitted by SE98-32482CJ on Fri, 10/08/2010 - 08:01

ou do what you wish but the generator will put out about 22 amps max. That will be about the requirement for the AC system so unless you are stuck in traffic--at night--on a hot rainy night with a battery that is already not 100% I would change.. But if you drive as most do a fully charged battery and a properly adjusted charging system you should be fine.

Submitted by petepratt@gmail.com on Fri, 10/08/2010 - 03:42

Ed / George, again thanks for each of your responses Ed, George is correct the fuel pump is the modernized SU fuel pump. One article i have come across indicates it can be changed, another indicates it is better to buy a new one. i guess it will be up to me to determine what I really want to do . A firm in Dallas offer's the alternator kit that is made with the fitting that fits straight into the PAS but as George i indicates, it is expensive being nearly twice as much as the standard generator.
.
George, I guess I missed out the main reason I am leaning to the alternator, after this particular hot summer here in Texas I plan to have air conditioning installed over the next few months and the alternator would appear to give out the additional power to run it. As the alternator is negative earth it seemed to make sense to convert the rest of the system .

Guys again hanks for the input. i will keep you posted on how this turns out .

Peter Pratt

Submitted by SE98-32482CJ on Thu, 10/07/2010 - 17:01

Edward he may have a modernized SU fuel pump--which is exactly as the orig. but with electronics instead of points--I am not sure they can be reversed.

Peter you need to fix your charging system and then simply isolate the radio (not touching any portion of the car body. If you are determined to do all of this work then change polarity but the alternator is not more reliable and the expense of changing to an alternator with a PAS pump or installing a seperate PAS pump will pay for 3 new regulators and 4 generator rebuilds.

Submitted by edjagm@comcast.net on Thu, 10/07/2010 - 15:53

Peter; Your generator at one end is coupled to the power steering pump all one unit, I believe making it difficult to convert to a alternator.
For the radio you can install a dc converter for negatine to positive ground.
Also the electronic fuel pump which is simular to a pack of cigarattes can operate both positive and negative grounds.
Good Luck

Ed Messikian

Submitted by petepratt@gmail.com on Thu, 10/07/2010 - 12:47

George many thanks for your quick response. I did really mean "'must" wrong choice of word on my part , George this all came about when I was brought a new radio by my son for my birthday I was not ready to install it at the time so I did not take much notice it was only in the last couple of weeks that I read the manual and the issue of the conversion came up the radio is of-course negative earth I had decided to let the radio specialist put the system in when the dynamo stopped charging I read and asked around locally and the general response was to fit an alternator more reliable and more efficient than my old dynamo but when I contacted a vendor in Dallas they informed me that the car needed to be changed to negative earth because that is the 3way the alternator comes My car has the original PAS and as such I would need to by the appropriate alternator. As I indicated the two items are the Electronic Ignition and the Fuel pump that I am having problems with as I have changed the wires around on the fuel pump but it just does not seem right. On the coil I have three wires not two as indicated in the conversion sheets I have swapped them over but because it is electronic ignition I am not sure that is right? George even I get all these two Items changed am I (with the dynamo not charging) unable to complete the fielding of the dynamo? I do have a couple of good manuals I will read again and look again at the dynamo and the regulator. Again thanks for your response most appreciated.

Submitted by SE98-32482CJ on Thu, 10/07/2010 - 09:21

Peter if you are not charging now --changing polarity will not correct that. First you need to correct the charging issue. You can check the generator by following the instructions in the service manual (and if you do not have one please look in the JCNA shoppe--this site). If the generator is fine then the regulator is next and the instructions are in the service manual also. Normally dirty points in the regulator are the issue and it may be a simple cleaning. Having said all of that the electronic ignition you have will have to be changed if you want to switch polarity--same with the fuel pump if it is electronic and not simply electric. What is interesting in your post is you say you MUST change polarity--why? Normally this is for a radio or cd changer etc. Instructions for changing polarity are simple and evidently you have them but they are almost always written assuming the car has stock equipment--please let us know if we can offer any more help--and good luck!

PS the sparking you refer to is called fielding and that is the last step in a change or if you install a new regulator or generator.