Negative Ground Conversion

Hi Guys/Ladies,

I've finished the deconstruction of my Mk3 and am beginning the loom work. I want to convert to negative ground and see little to get in the way, with the possible exception of the Ignition Warning Light Controller. I'm using a Sparx 3-phase alternator and Rectifier/Regulator, which is compatible with negative ground, as well as a Pazon Ignition. I would love to hear from someone in Norton-Land who has done this on a Mk3 and could tell me that it is a piece of cake. I sucessfully converted my TR3A, upgraded to an alternator, but lost the ignition "idiot-light" function in the process. As the car has an ammeter, there was little at risk, but I really want to keep the Norton ignition light fully functional. The search results in this forum are a bit dated.

Thanks,

I have beat this subject to a pulp. If you look for threads that I started you will find your answers. I tried it with the rectifier/zener set up and it didn't work. With a voltage regulator it can be done. I'm gonna put it back that way when I pull all the grounds to one post.

I haven't done the conversion myself, however it should be reasonably straightforward and others here have done it.

I'm not exactly sure if the MkIII assimilator will work negative ground or not, but there are other devices that you could use instead, such as the AO Services LVS unit: http://www.aoservices.co.uk/data/lvs.htm

And you could probably fit one on your TR3A?

Negative Ground...A Positive Improvement

I am doing the same thing on a '75 Mk III.

I have the Sparx 3 phase and a Pazon which fires a wasted, spark coil from the Colorado Norton Works. I am using marine grade tinned wire with Crimp-a-seal connectors (realy cool crimp ons that have heat shrink collars) http://www.sherco-auto.com/krimpaseal.htm

My plan is to run a master ground from the headlight to the tail light, probably 14 ga, and not assume that the frame or the engine can be a conductor, but rather to deliver a ground directly to the component that uses electricity. I will be wiring the starter with 8 ga, but I have my starter rebuilder welding a ground lug on the starter case so that the 4 brushes will have a straight forward current path back to the battery; I will be using 16 ga wire for all other missions, 18 or 20 where I can take advantage of some micro relays such as the starter solenoid circuit and the horn circuit; that way the horn and the starter solenoid will have working current paths that are less than 10 inches and no high power will be going up the frames backbone with the limited exception of the headlight circuits.

Just a small side not on the starter: In the Norton Tech Digest are part numbers for converting the PresoLite starter to a *real* four brush, four field high power starter. My rebuilder was able to get the field coils, the brush plate and the spring set for less than $40.00. After he turns the armature, replaces the bronze bushings and puts it all back together with the grounding lug, it will cost me a mere $110! (the same price you pay for the bogus 4 brush conversion plate part(s) alone!).

Make sure that you tie a tag or place a decal in the batterty area stating the the machine is negative ground.

Your wiring will eliminate a lot of problems. Excellent choice of materials. I would like to ask what you are using for a crimping tool? I plan on rewiring with Krimpa-Seal connectors and currently use a Channelock crimping tool.

My rebuilder was able to get the field coils, the brush plate and the spring set for less than $40.00.

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That's an excellent price. I can get brushes, springs, and brush plate for around $40, but new field coils cost me about $40, so I usually look for a good used Harley housing with coils which usually costs me $20 or so. Removing the old coils from the Norton housing is a pain, so facing the labor (struggle) involved and the plentiful supply of cheap Harley housings, I take the easy way out. :lol:

JimC said:

I would like to ask what you are using for a crimping tool?

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I have a humble, but new Craftsman model 73575 crimping/stripping tool that handles wire gauge from 22 to 10; if the wire is smaller or larger, I use my teeth :lol:

The field coils are coming from PrestoLite; I'm sure that I am getting a good price; I have been using this service for over 30 years. These guys can actually remove and replace cummutators...

RS

Thanks for the info on Krimpa-Seal. Do the bullet connectors fit the standard Norton bullets?

Bite the bullet...

Lucas bullet connectors male and female parts, like the Krimp-a-seal have cannelures, essentially groves and buldges, that allow them to interlock and remaine reliably connected for the environments they are found in (my mind now drifts back to cruel cuts at Lucas electrics, like: Prince of Darkness...Why to the English drink warm beer...).

The bottom line is that mixing different connectors is not a good idea any more than trying to put an 18 inch tire on a 19 inch rim or vice versa. If you want to *repair* your Lucas wiring harness the Lucas bullets (male ends) are readily available on E-bay, I haven't seen the female counterparts.

If you are rewiring your ride from scratch keep the connectors confined to one manufacturer, or at least keep each circuit faithful to made-for-eachother components. If I have any question about the steadfastness of any connection I pull on it and ask myself what the bike could do to it and pull that much harder; if it breaks, I remake it.

A small side note here: Crimping looks easy, intellectually there isn't much to it, but in actuality it is rather easy to miss crimp a connection; some do it too lightly (where's the beef?) some do it to masseration (AND THE WINNER IS...). You got to practice... Here is what I suggest:

Get a buch of connectors, doesn't matter what they look like as long as they are what you will be using. Make sure that you match the connector to the proper gauge of wire, they are color coded (yellow, blue, red--the most popular). Make sure that you strip the right amout of insulation, the conductor should be readily visible about 1/32 inch beyond the crimping zone. Crimp a few to get a feel for how much energy they take to contract; I know it looks ugly, but if you have done it right you have more than enough surface area to cover what is referred to as the "skin effect" for electron transfer. Now to test your brand new connection...Pull on it until it parts. If you have done it correctly you will know instinctively that the Norton could never exert such a force. You kill a few you spare a few, but you build CONFIDENCE in your ability to do it right so that when the Norton fails to take you home, or to well deserved conjugational (could be home --as well) visit some night (or day--fancy that) you won't be looking for electrical Gremlins.

Ride an hour, work and hour---the old (and I hope it stays old) Norton mantra...

RS

it is rather easy to miss crimp a connection; some do it too lightly (where's the beef?) some do it to masseration (AND THE WINNER IS...). You got to practice...

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A couple months ago I bought an Xcelite ECP-112 ratcheting crimper. I was tired of manual crimps that slipped or deformed. This thing is great! It has three dies for different size open barrel terminals, but I have found it does and excellent job on most covered terminals as well.

I am putting some WeatherHead connectors on my cafe racer and this is just the ticket for crimping the pins. The WeatherHeads are overkill, bulky and expensive, but are certainly a permanent solution to sealed quickly removable connections

Good timing with this thread as I'm venturing into a MKIII rewire to negative ground. I'm also going to use a Sparx 3-phase alternator and Pazon ignition.

If it would ever warm up around here I could get down to business but it's been -30 C up here since before x-mas.

I'm also going to sue Sparx 3-phase alternator and Pazon ignition

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:shock: :lol:

And I thought the US was a litigious society!! :wink:

Ron L said:

I'm also going to sue Sparx 3-phase alternator and Pazon ignition

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:shock: :lol:

And I thought the US was a litigious society!! :wink:

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Just fixed the typo.

Anyone know the original method of attaching the connectors used by lucas? They look like a heat solder/crimp method and we know how well they hold up.

The bottom line is that mixing different connectors is not a good idea any more than trying to put an 18 inch tire on a 19 inch rim or vice versa. If you want to *repair* your Lucas wiring harness the Lucas bullets (male ends) are readily available on E-bay, I haven't seen the female counterparts.

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I understand what you are saying here and agree keeping everything the same makes a lot of sense. However utilizing part of your old wiring harness makes a lot of sense. Like the rest of the electrics, Lucas connectors are not rocket science and can be inter-racially mixed with other brands of connectors of similar design and dimension IMHO. Back in the 70's I was lucky enough to stumble on some connectors at the local auto supply that fit very well into the lucas barrel connectors but I always soldered and shrink fitted them as the insulation on them was crap. When ever I built a new wiring harness I soldered everything. Crimping was just a means to hold the connector in place till the solder flowed and set. I only lightly crimped so as not to misshape the fitting. (maybe I never tried a good crimper).

Here is a stock female barrel connector(1972). It has only an indent on one side at each end to lock the connector in. The rubber housing would add to the tension on the sides of the tube.


After you've taped the harness up and decided to move a component or change or add something at a later date a good crimper would be a convenience until you could properly solder it.

The Krimpaseal solder connectors look interesting.

After you've taped the harness up and decided to move a component or change or add something at a later date a good crimper would be a convenience until you could properly solder it.

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Each to his own, but IMO you are asking for a problem(s) when you solder wires on a motorcycle. Any time you solder a wire it becomes prone to breaking from vibration. Notice how no electrical connections are soldered on your four wheel chariot. There have been a number of posts here about the mysterious Boyer pickup wire failures. Good crimp connectors, such as Ron L. suggested, with a proper crimp tool. When I worked for Lockheed Missile and Space, I learned crimping was a science unto itself. The shrink fit sleeve serves two purposes. Besides protection from moisture, it provide a stress relief. Stress relieving is especially critical where there is a lot of vibration.

Hi Jim
Yes to each his own and it looks like automotive type crimp connectors have improved in the 25 years since I've used them. The only solder connection I ever had break (for what ever reason) was on an ignition capacitor. The blade connectors are only soldered onto the end of them from the factory. I re-soldered that though and it never was a problem again. All I can say is I never had any problems with my wiring after that.

JimC said:

Your wiring will eliminate a lot of problems. Excellent choice of materials. I would like to ask what you are using for a crimping tool? I plan on rewiring with Krimpa-Seal connectors and currently use a Channelock crimping tool.

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JimmyC,

I am soldering the bullets. As long as heat is removed as soon as the solder flows, there is little solder penetration below the bullet. I apply a heat-shrink tube to seal the bottom as well as give a bit of support to the joint. As an EE, I found that the techniques for successful soldering are easier to master than those for crimping. In 30 years of designing and testing electonics in a 175C 100 g shock environment I've never witnessed a failure of a properly soldered joint. I'll continue to dance with who brung me.

Regarding socket pins, I'll defer until I see the products supplied by British Wiring. If I can solder the pins, I will.

Crimping is widely used in a manufacturing environment today because it is much faster than soldering and amenable to automation. As I enjoy every minute of my renovation projects, time is never an issue.

Yup,

I often use a heat sink when soldering to prevent excessive penetration.

Cookie said:

Yup,

I often use a heat sink when soldering to prevent excessive penetration.

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Roger that, Cookie. A small heat sink placed on the wire just south of the bottom of the bullet makes the job bulletproof.

Hey Ricky in Seattle,

Do airplanes use solder?

I doubt there will be problems with most soldered bullet connectors on a Norton if the connector is not solidly attached somewhere. Where there is a likely problem would be a soldered lug attached to a terminal strip, with the strip attached to the frame. Any solder beyond the terminator is a problem when it is subjected to vibration. Especially if it is not stress relieved.

JimC