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MG MGB Technical - Wiring Harness Choice

My 67 BGT restoration is nearing the wiring harness portion of the project. It is going to have the Moss A/C kit installed so it will get a alternator to go along with the air conditioning unit.

What wiring harness do you think I should get as I want to be ahead of wiring changes as much as I can. This need not be original but the dash, lights, heater and remainder of the engine compartment is pretty stock. I will need simple though as I am electron challenged but can follow basic instructions and pictures are even better. Is the Moss kit quality? Original 67 BGT would have been cloth covered but the new Alternator and A/C will have to be factored in. Anything better out there that is reasonable and would work well?

Appreciate any comments or experience you have for me. BTW the Moss Alternator kit, with bracket and instructions is about $250... the old midget bracket is available ....is there another (less) alt to use and can be a simple wire in or is their Alt. kit the way to go also?

Thanks Ralph
R Stegs

Ralph. Can't comment on the wiring. I have the original in my 67 GT. As for the alternator. Buy the Moss Bracket separately. I had to slightly file the bolt holes to get it so the alternator was in the correct position in relation to the fan belt.

You can purchase a rebuilt Lucas Alternator fairly reasonably from most parts houses. Size you get would depend on what other accessories you will be running. I think I am running a Lucas 60. My rebuilt came with a 3 year warranty. Got it through Advance Auto Parts.
Bruce-C

You can take a look at these Alternator conversions at this site: http://www.cibolas7.net/17901.html Both are relatively easy to do and provide an alternative to a Lucas unit, if that matters to you.

When replacing a generator with an alternator on a 67 B, know that you must also change from positive to negative ground as all alternators, regardless of who makes them, are set up for negative grounding. Also, you will need to either buy or fabricate a new rear bracket for the alternator as they are all shorter than the generators used. Go out to Barney Gaylord's MGA site (linked on the webpage above) and follow his directions for doing this, or check in with Moss on their site for similar instructions.

As for the best harness, I would suggest that a harness for a 69 MGB would probably come the closest to both that in a 67 and have less "extra" wiring to contend with than those that came later. There will be some differences, and altho a 68 might seem to be better choice, it has wiring for a separate voltage regulator rather than a built in one. Alternators, Lucas or otherwise, that you will most likely use for your conversion will generally have integrated, not separate voltage regulators and so you really don't need the confusion of the 68's wiring to deal with.

You might also check with the various harness makers (British Wiring, Rhode Island Wiring, etc) and see if they could work with you to create a harness with the proper wiring in place for your car. Harnesses are often built singly or in small batches, and they may be willing to help you create just what you need without having to modify some other year's harness. Just a thought.
RK Muenchausen

You could also contact Steve Carrick at Advance Autowire

http://www.advanceautowire/com
Rick Ingram

Guys thanks for the information. The 69 harness is a great idea. Rick, I did not have any WEB success with that link. Regards Ralph
R Stegs

Rick's link should read www.advanceautowire.com with the slash replaced with a dot. The harness they sell looks to be of very nice quality, with relays carrying the loads and all. Not sure if the price would be considered "reasonable" but the quality appears to be there. Also, their schematics are extremely helpful, much better than found in the owners manuals.
Erick Vesterback

My bad....try this:

http://www.advanceautowire.com/
Rick Ingram

Ralph:

I put the Moss a/c in my 67 GT. I also upgraded to a new harness (cloth covered).

Pete Cosmides of Motor Car Garage in NJ did the installation for me. If you need advice about the a/c, the alternator or the harness, contact him at:

http://www.motorcar-garage.com/default.asp

He gave the tech-session on installing the Moss a/c unit at MG 2008, so he's the guy to talk to.

Bernie
Bernie Lowe

I have an AdvanceAutowire loom I bought some time ago but haven't fitted yet (getting close though) and it is really nice quality. The wires are much thicker than the originals and it comes with modern blade fuses and relays for all the appropriate things that need relays.

Also for me an advantage is my car is non standard and this loom allows me to wire it up the way I want to.

Simon
Simon Jansen

You can also try http://www.britishwiring.com/
I saw them at MG 2008 and they looked like they can set up any loom you need.
Ed Emery

Thanks guys. Simon, do you think a reasonable hobby mechanic with little electrics background could wire up a fresh (starting from no harness) restoration/modified project based on what you have?

The website talks about a need for a basic understanding etc. I have installed a couple basic (with instructions) 50's era harnesses on other non British projects. Those were connect the dots simple though. Ralph
R Stegs

The Advance harness comes with its own wiring diagram (as it may be custom made to your application). Steve attempts to use the same wiring colours as factory.

As you will have a custom install, it will most likely take longer to install...and you will need to wrap the wiring to protect it (or use the plasctic loom protectors available at most auto parts stores, etc.

It's not going to look factory...but will perform better than factory (in my opinion).

I have a British Wiring harness in my MGB...and one in my 1969 MGC. They are of good quality and function as well.
Rick Ingram

I ordered an advance auto wire harness $550.00 in Dec. 2008, I received the main assembly Jan. 28, 2009 with a promise of receiving the additional relays shortly thereafter, nothing! I have called, emailed, no response what so ever. I hope maybe Steve will read this and attempt to contact me. I would like to know where I am at on this deal.
Geoff Lund

Ralph, it is hard for me to say really. I've been doing electronics since I was a kid so it is easy for me.

I think you should be fine if you take your time and make sure you know how each thing you're connecting to is supposed to work. If you can use a multimeter to measure things (buzz through contacts and measure voltages) you should be fine.

It's no more difficult than any other job on these cars really and if you've done other looms before I am sure you'd get through!

Simon
Simon Jansen

This thread was discussed between 29/03/2009 and 03/04/2009

MG MGB Technical index

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