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MG Midget and Sprite Technical - Engine bay electrics

I've decided to rewire my engine bay. Reasons are plentiful:

1) The headlamp wiring connections are a powdery mess, and a PO has butchered an air horn relay into it.
2) I'd like headlamp relays and halogen lights.
3) My fuse box is a powdery mess too.
4) The lucas box is barely servicable and at last measure was charging at about 18 volts.
5) The loom is brittle and damaged in several places.
6) I fancy an electric fan too.

So, I'm thinking of an engine bay rewire. Ideally I want a couple of big connectors where the loom passes through the bulk head, and then rewiring the dash and rest of the car is a job for another winter.

I'd like to swap to an alternator at the same time.

So, questions:

1) Which is the most cost effective alternator to get? I don't want anything special - 50 or 60 amps should be fine.
2) What alternator brackets do I need? New pulleys too? Does it all align with the water pump and crank?
3) Is it possible to split the loom at the bulkhead? I'm thinking that I could end up with the rear lights still feed from the stalk but front ones on relays. That would complicate putting it all on relays when the rest of the car is rewired next winter.


Thoughts and advice appreciated - as ever :o)
Ant
Ant Allen

I can give a little advice on the alternator. I fitted a ford escort alternator (45 amp I believe) and was exactly correct at the front bracket. All I needed then was the extended rear bracket that is hard to find and the job was done. I would have been confident of making an extended rear bracket by modifying my original had I not been able to find a correct one.

I totally rewired my car using wire from my existing loom a circuit at a time by puting in 2 new 8 way fuse boxes, one for ignition on and one for ignition off. Ran from each fuse to a switch then the cicuit, far better than the basic original 35 year old crap. although the wire was still OK
Bob (Robert) Midget Turbo

There are a number of alt. you can use, most likely if you dont use a standard lucas alt. then its going to take some thought ad imagination, but its not that hard to "invent" some mounting brackets

Id strongly consider using a "single wire alt" with a built in electronic regulator this will eliminate alot of head scratching...Im using a GM alt of the above assemblage

here is a wiring kit Im planning on useing when I do my re-wiring project later this next year...they dont decribe it vary well, but in other info I have found it to be the cats meow


http://www.painlessperformance.com/webcatalog/largeview.php?SearchField=10202&SearchAll=Street%20Machine

the reason I like it...

all the wires are labeled every 6 inched,(aka fuel pump) everything is on its own circuit, lots of room for expansion, the wires are all high quality, and supposedly good support, and can be adapted to todays modern convenances...holigen head lights, power radio systems, ect.

prop
Prop

There's some good info on alternator conversions here...
http://www.teglerizer.com/alternator/
and here...
http://www.madelectrical.com/electricaltech/delcoremy.shtml

As far as the fuses go I'm in the process of doing what Bob did, I picked up a couple of nice 6 circuit panels on ebay, however I'm moving mine into the glove box.
I really don't think you need to split the wiring at the bulkhead, just separate the headlight wiring when ready - all the wiring you need to get to to do the fuses are on the opposite side and under the dash.

Bud


Bud K

Ant

I have used this comapny in the past and found them very good, they do all the wiring you need in the tracer colours you want also.

PS I have no affiliation apart frombeing a satisfied customer.

Oh could we add that to the wiki, supplier lists and what they are good for.

Shaun
Shaun

In case you guessing Doh!!!!!

http://www.vehicle-wiring-products.eu/VWP-onlinestore/home/homepage.php

is the company

Shaun
Shaun

Excellent advice. Thanks chaps.

To keep it simple, what lucas alternators are there out there? Can I just get one from a metro or 1275 mini?

Ant
Ant Allen

yes you can
Onno Könemann

Yes,
but you'd need to change the rear mounting bracket.
While your about it take the fan from the metro & thermostatic switch & bung in the radiator as well.
Brad
Brad (Sprite IV 1380)


Regarding splitting the loom at the bulkhead - if you look under the dash at the far right-hand side, there's a big bundle of connectors there, which pretty much separates the loom. There are also a number of connections which come straight through to the dash, and to be honest you might find it as easy to re-wire the dash at the same time.

I got lucky and got a complete wiring loom from an early alternator car for peanuts on Ebay. I used the engine bay portion and it is so much neater than my old loom which had been butchered in a very messy way to fit the alternator.

That worked perfectly with my 1973 RWA as it was otherwise identical. I'm not sure what year your car is, or about the similarities and differences with older cars, but would imagine it causes more problems than it's worth in older models?
MarkH1

Mark: Thanks for the advise. Mine's a 71 Sprite.

Brad: Does the thermostatic switch screw into the radiator on the metro? Where on the sprite rad will it go?

Ant
Ant Allen

Ant,
on the metro its on a bung in the radiator, best take a couple if you can. On my sprite i've got it on an adapter into the top hose. I also use a switch so i can turn the fan on when in traffic.
I've a few photo's if your interested.
cheers
Brad
Brad (Sprite IV 1380)

Ant,

When i did my Heritage rebuild my donor was an early RWA 1972 originally with a dynamo and rocker switches - i got a new loom for a rwa alternator car (pre hazards) and fitting was easy. As Mark says this way you get a much neater instal as you do away with all the unnecessary dynamo wires.(you will need the later tacho RVC type - as the loom is wired for the electronic tach - better as current is not run through unit IMHO)

If you do rewire the dash - cut off the old wires leaving an inch or two of wire on each contact/switch etc - that way you can follow the wiring colours as you replace each bit.
I had a couple of minor issues with bulb fittings in the tacho ? if i remember correctly.


The rear alternator bracket came from Moss 12G1053 listed as £7.65.

Richard.
richard boobier

Ant,

I did the same as Richard on a 71 midget which was originally dynamo. The loom splits at the bulkhead so you can just buy a front loom but if the front ones loooking dodgy the rear one probably won't be much better.
Bought the loom, brackets and alternator from Welsh MG and fitting relatively straightforward.
Had the same issue with some bulbs but it was the indicators!

Jeremy
Jeremy 3

Lucas 18ACR 43 Amps charging (thats enough) and with the bracket mentioned above its a neat swap.

You can order the Lucas 18ACR from generic partssuppliers. Ask for the 1979 or 1980 MGB alternator. They still have them listed.

I recently rewired the front of my car using a couple of relays and 3 fuse units with in total 12 fuses. Now everything has its own fuse and switches arent pushed to the limit.

All electrics reacted as if it were new, stronger wiper, much more headlight output etc.

Put the relay as close to the device as possible. That way the low current loom is long but doesnt supply to the device and use some new big wires to deliver the current to the devices. I used 4mm2 and even 6mm2 to supply the front.

Bas
Bas Timmermans

Try Mini breakers too, lots on Fleabay, got a good alternator for £10 and the bracket (you need early, not late A+) for a quid!

AndyB
a borris

Ant,
you have mail.
Brad (Sprite IV 1380)

my electric fan switch.
http://www.eatworms.org.uk/album/album2.php?album=Midget-Dash&mode=page&index=11

and additional fusebox
http://www.eatworms.org.uk/album/album2.php?album=Midget-Dash&mode=page&index=10

those relays are for fan, air horn and Switchec accessories.

I have relayed the lights on the other side.
Dean Smith ('73 RWA)

Dean,

The horn is the device I havent relayed yet. Can you discribe how you did that? Is it hornpush operated and wires as the normal horn?

Bas
Bas Timmermans

Dean,

Found the info. The last picture is a wiring diagramm. It shows the new airhorn being relayed, not the original ones.

Anyone else put a relay in the original horn circuit?

Bas
Bas Timmermans

This thread was discussed between 21/12/2008 and 28/12/2008

MG Midget and Sprite Technical index

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