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MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGB GT V8 Factory Originals Technical - Custom wiring harness

FWIW: I have revised and upgraded the design of the custom wiring harness that I published in the May 2001 issue of the British V8 newsletter. The complete "how-to" instructions for building this wiring system may be found at http://www.britishv8.org/techhome.htm

This is a 14 page document, in pdf format, with complete instructions for building a relacement wiring system for any British car, but the instructions use an MGBGT as the example. A complete list of parts is provided, along with the source and price of the parts. The design includes an easily fabricated, home-built panel, with 6 relays, 8 fuses, two flashers, and a power terminal. Total cost for the parts will run around $300, and includes ALL the wire needed to replace every wire on your car, maintaining the orignal MGB/Lucas color code.

At the risk of being hunted down by the ethics committee and boiled in oil for advertising, I want to let everyone know I will soon be offering for sale complete kits of parts for this system, using a better grade and larger gauge wire than can be bought by individuals in small quanities (I buy wire in 1000 foot spools, and I have purchased over 85,000 feet of wire for this project), and a pre-fabricated mounting plate, but the price will be competetive with what you could buy the parts for yourself. I'll also be offering a few pre-assembled kits as well. Pricing and availability TBA.

I'm not doing this to make money, so I don't care if you buy from me or from the sources listed in the article, but either way, I recommend you take a look at the article and see if this is something for you. I only want to sell enough to recover my investment and to help other British car owners.

One of the things I dislike most about an MGB is the rat's nest of wiring under the hood. This will get rid of that, and give you a modern, reliable, wiring system, with the fuses, relays, etc, mounted inside the car, out of site and out of the weather.

Regards,

Dan
Dan Masters

One thing Dan,

Great idea, but what about the voltage to the fuel guage, this should be from the voltage stabiliser?.
Tatty

Tatty,

Yes, you are correct if you are using the stock gauges. I showed aftermarket gauges in the diagram because I assumed most of us will be using them rather than the stock gauges. Aftermarket gauges don't need the stabilizer. In fact, if you do use the stabilizer on aftermarket gauges, not only will they be inaccurate, but they will swing back and forth as the stabilizer cuts in and out.
Dan Masters

Tatty, I agree with what Dan says, just ask me how I know!! :-P Cold, hot, Cold, Hot..
Larry Embrey

Cheers Dan,
Tatty

"Cold, hot, Cold, Hot.. "

So, Larry, on average comfortable, then?
Paul Hunt

Great instructions Dan but I ran into a problem when I downloaded it. Some of the pics didn't come over and the schematics had a large blacked out area?? Anyone else have this problem?
Guess I will get in line for your kit this summer for my V6 conversion.
The tech area is going to be a real goldmine once you start adding all the material to each topic. Great job!
Thomas Rynne

Paul,
Thankfully the needle would hit the correct temp before dropping down. I just had to watch it for a couple sec to see where the needle was peaking out at..

Dna,
Well done. I am glad to see you are finding time to continue on this endeavor. I look forward to seeing your completed kits.
Larry Embrey

Thomas,

I just tried to download the file myself, and it came through perfectly. You might want to try again. If you still can't get it, let me know and I'll try to get a copy to you some other way.
Dan Masters

I had no trouble downloading it
Bruce

The problem is not in the download it is once it is down. Apparently you might have used something that did not save itself to the PDF file and is still "linked" from your computer. I had lots of missing pictures and black grids as well.
Larry Embrey

I had a 3.1 issue of the PDF reader so I downloaded the later version on Dann's web page and that solved my problems. Again, thanks to Dann and now I have yet another project for my V6!!!
Thomas Rynne

Thomas, Good catch, i just rebuilt my machine and did not upgrade my acrobat afterword hehe will try that..
Larry Embrey

Yup that solved it. Everyone make sure you have the latest Adobe and you are good to go.
Larry Embrey

Dan, a good article well presented. My only critisism (please take it as constructive )is the basic ignition cct.I think this would have been a good time to add a ballasted option. Barrie E
Barrie Egerton

Barrie,

I didn't include the ballast resister for a couple of reasons: I don't think many will want to use one with a V8 conversion unless they are required to keep the pollution control equipment, and I was primarily concerned with the Power Block portion, only including the remaining wiring in the diagram as a reference, as each application will be different. I wrote an article on deleting or adding ballast resisters in an issue of the newsletter a few years back, so I guess I could add something on it to the tech tips page if there is enough interest.
Dan Masters

Dan,
I'd definitely like to see another tech piece on the function of ballast resistors. I need all the info I can get on pros/cons on the subject. Just to indicate my interest.

Thanks,
Joe
Joe Ullman

Dan, Et Al;
I thought I would add this as it has a good relevance to this new wiring issue.

I JUST recieved my shipment of "delta switches" from Europa Spares in the UK. These are direct modern replacements for the rectangular rocker switches found in late model MG's. They have a wide selection of configurations and switch types.

Since I have 4 spots for switches in my 78 dash I decided to fill up the dash. I purchased 1 hazard, 1 light and 2 fan switches. The fan switches are dual position just like the stock heater fan switch, with off/on/on. The rest are "on/off" type. The connections on the backs of them EXACTLY match stock MGB wiring, so they are plug and play simple.

The switches have a more modern rounded edge to them and the action seems nice, The icons are large and easy to read. My battery is pulled so I cannot test the lighting in them but I think they either are lit all the time or they lite up when activated, I will let you know on that when I fond out.

Total cost for the 4 switches with shipping from UK was roughly $40.

I will be putting pictures up of the old and new next to each other so you know what they look like. It will be in the Nov2002 page of my V8 diary later tonight.
Larry Embrey

The function of the ballast resistor is to enable the coil to deliver a better spark during cranking. When cranking the battery voltage drops to about 10v even under ideal conditions as opposed to 14v when running, i.e. a potential (ho ho) 40% or more drop in spark energy at the worst possible time with a 12v coil. By running a 6v coil in series with a ballast resistor the running spark energy is about the same, but a special contact on the solenoid delivers full battery voltage to the coil during cranking. As this is going to be around 10v instead of the normal 7v (half of 14v) you can see than far from getting a drop in spark energy when cranking, you get about a 50% *increase* in spark energy. This is particularly necessary with the weakened mixtures of emissions controlled cars, but is beneficial to all cars under adverse conditions e.g. low temperatures, less than perfect battery etc.
Paul Hunt

I recently gutted the "prince of darkness" Lucas electrics out of my '66 B roadster. I replaced it all with a Centech GV-10 street rod wiring kit. The complete kit cost $249! I had enough wire left over to do half of another car (since the B is so small). This kit comes complete with all the wiring for a complete guage package, plus circuits for all those goodies that street rodders love, power windows, elec. fan, AC, etc. This is by far the BEST thing you can do to a B. My lights and turn signals are brighter than ever, & I wired in 4-way flashers. All the stuff you need is included and the new horn relay (included) makes my dual (whimmpy) B horns blast with authority.
Patrick Kaye

To add to Dan's article. There is a company in the Midwest that is currently undergoing the possibility of producing a very simple plug and play harness and ECM/ECU system for the fuel injected GM 60° 6 cylinder engine both FRD and RWD type engines. I have looked at Dan's manual for the Triumph TR 250/TR6 and his custom wiring panel is very compatible with the proposed FI ECM/ECU and harness system.

This is real good news and it brings the cost of installation to an even better, affordable V6 installation.

I will keep you members aware of the progress if you desire. Dann
Dann Wade

As far as the function of the ballast resistor, it's out of the circuit during starting, but feeds the coil during running? Yes, I think I see. I know that I have a brand new ballast resistor stuck away, and a new coil, for when I get that far in the conversion, and some instructions that say something about whether to use it or not. I would think the Mallory coil would have typical internal resistance, telling me if it's a 6 or 12 volt coil, as well. Seems like the mini torque starter also has some small terminal that has something to do with the ignition circuit. It'll be exciting reconciling all this when designing the electrical part! Hey, that's what fuses are for!! Joe
Joe Ullman

Joe,

The extra terminal on the starter is wired directly to the + terminal on the coil. It is only active when the starter solenoid is energized and provides the ballast bypass for starting.
George B.

Joe,

I just remembered - I wrote an article on ballast resisters for the VTR website, at:

http://www.vtr.org/maintain/ballast.html

I also wrote an article covering this for the MGV8 newsletter, in issue III, Vol 2.
Dan Masters

The factory ballast is a length of resistance wire hidden in the loom. Some aftermarket coils come with their own resistor. It is important to wire this back to the white or white/brown at the fusebox and not pick up the existing coil +ve feed as you will then have two ballasts in series with the coil and consequently weak sparking.

The high-torque starters I have seen where the solenoid is almost as big as the motor, and the pinion gear is in line with the solenoid and not the motor, do *not* have the extra terminal. In this case you can achieve the same effect with a relay, or even a suitable diode.
Paul Hunt

Here is a site that might be a good source of info for those who don't have a good grasp of electrical component functions in automotive applications.

http://www.mercurycapri.com/technical/electric/index.html
Dann Wade

This thread was discussed between 13/11/2002 and 25/11/2002

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