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MG Midget and Sprite Technical - new headlights and spot lights

Hi fellow forummers, that's a good word!
Anyway, I'm going to replace my headlights with halogen got them already, straight forward wipac set, I also want to install my two vintage Lucas spots, I would like the spots to come on with full beam, as electrics is not my strong point, any tips on wiring them up, my wiring is pretty old, original, I would say, I don't want to replace the whole loom at present, that's a winter job, I want to keep using the car now the good weather is here.
I was think of replacing the front wires going to the lights/horn, does not look too difficult, would it make sense to cut and replace with new wires and rejoin with connectors, or is this a bad idea, should I just work with old wires, and replace the loom when I can?
cheers Jack.
Jack New Forest

Yes you can keep the old loom
But with the addition of halogens and spots i would add atleast 3 relays.
Though some say the relays are not needed since the halogens have the same wattage they do add a lot of light due to a stronger feed of power.

So get 3 30 amp relays (fuses preferably)
Mount them on the drivers side inner wheelarch
Get a direct power feed to them using thick gauge wire from the starting relay
Fit ground wires to one side of the coil
Disconnect the main and dipped from the nearby snap connector
Feed the dipped to 1 relay and split the main to 2 relays
Feed the outgoing switched to the relevant wires to reconnect main and dipped and pull an additional wire to the spots from the 3rd relay.
Mount and ground the spots and it should work

The relays where a bigger improvement for me than the halogens
Onno Könemann

this may be a duplicate of what Onno posted (we almost did at the same time)

Hi Jack (never say that to an airline pilot, even if that's his name),

The OEM harness is wired with plenty of margin for a quite significant increase in bulb power, but if yours is suspect (you indicate that you are planning a future re-wire), then the easiest way to make sure your wiring is safe is to run a dedicated feed for the bulbs and just use the OEM wires to switch a relay that you add, located in the engine room somewhere.

To do this, you will run your own power wire from the battery (or from the "hot" terminal on the starter solenoid, where the thick, brown wires are all connected together) to your relay, and from there to the lamps.

The control for the relay you'll tap from your existing harness by unwrapping some of the harness tape somewhere in the engine room, or by running a wire back from where it used to connect to the headlights to where you put the relay. The wire you want is the Blue / White wire, as this is the "switched" power from the IP control switch.

By using that blue/white wire to operate a relay, and running a new wire from your battery to this relay, and then from it, on to the lights, you'll need not worry about any of the original harness getting over loaded, or having been chafed / damaged somewhere and getting into trouble with this increased load upon it. Also, doing this will prevent your switch from seeing large loads (using a relay is a great way to get the maximum life out of any switch that is controlling several amps of power).

for wiring a relay, there is a little diagram printed on the side of them. There are also kits available to help out if you have difficulty with that bit.

hope this helps!
Norm
Norm Kerr

Onno,

Ref your comment "Though some say the relays are not needed since the halogens have the same wattage they do add a lot of light due to a stronger feed of power"

The reason halogen lights give a greater light output is due to the greater efficiency of them and not 'stronger feed of power'. I recall the increase is ~30%.

As always, I am open to correction.

HTH
Doug Plumb

I know the math

And i have also seen several lightswitches go up in a puf of smoke after halogens being fitted.

So there must be a difference.
I think the halogens pul a slightly higher peak when switched on.
Might be minor but enough to fry a 30 year old switch
Onno Könemann

Two relays are the best option.

Spotlights are then just a fashion accessory
rachmacb

But Rach

you need spots to irritate the hel out of the xenon oncoming traffic ;)
Onno Könemann

Thanks Onno and Norm, well that sounds complicated, you would'nt like to pop in and do it for me Onno, Norm your too far away ha! ha!
Only joking, lots of good advice there lads as usual, I'll have to get some wire now, and digest what you have told me, I hate electrics, so I have to really be sure I understand what Im doing. I'll read everything twice just to make sure.
Listen out for the bang!
Rachel what you on about, I hope my spots are of use not just for looks, it's dark in the new forest at night, no light polution.

cheers Jack.
Jack New Forest

Jsck

wotcha!

It really isn't very complicated

I drew this diagram to cover headlamp relays for a Mk1 Sprite but if you look at the relay and the headlamp part of it you can see how it all goes together

Your switched power goes to a relay instead of into a headlamp and the reduced power demand allows the (now) elderly switch gear to handle the current by only working the quite "light demand" switching coil inside the relay.

This can help the switch stay in service for a long time. In here we have had many examples of "new" make replacement switches for almost any electrical circuit in the car fail miserably soon after installation

Relays take the load instead of the switch

When you have your relay in circuit switching it can then supply power to the lamps from a fresh, clean power supply off the battery not using the cars old wiring

Power for this is applied to "pin 30" on the relay, then out to the bulb holders in the lamps

Study this and any other pictures for a while before you tackle the job

Shouldn't have to be much of a pain in the butt

All very basic, 'specially if you are only relay powering the main beams

You can make the supply to your spotlights operate the same way

I hope this helps you, if it doesn't, ignore me

Most do :)

New forest

lucky geezer

one of my fave places is Lyndhurst

And Beaulieu too of course


Bill 1

Halogen bulbs are brighter because they use higher filament temperatures, not nec more supply current. They can run at higher temps without the filament evaporating very quickly (and the bulb 'blowing') because the halogen gas takes tungsten from the glass (the dark colour of an old bulb) and returns it to the filament.

Very clever.

They often have a smaller filament that allows them to be focussed better, too, compared with the old bulbs.

Aren't LEDs becoming good enough these days for headlights? These use much less current....

A
Anthony Cutler

The new led lights are running brighter and some of the spotlights made from them have a muc nicer glow than the older ones.

I live in the middle of nowhere with no street lights for miles and have never needed anything more than halogen lamps even through the forests around here - just the relays to make it more of a steady light.

Not knocking spotlights - will have them on the B - but purely for the hell of it, not because I need them!
rachmacb

Rach
You are just not going fast enough ;)
Onno Könemann

LOL Onno - wanna bet?!?!?!?!

It's not like I can race any of you - you've bought your new toy so can't afford to come over - and Arie's too scared too ........ BTW - I did find your autotest results online from MGlive the other year ...;)

Not sure what a deer sitting on the front of a midget would look like - but I'm willing to give it a try at Midget50 if someone pays me enough :)
rachmacb

Crap.....
It was my first autotest ever.
And my last I like track driving and rally's better
Onno Könemann

LOL - I think that that's a feeble excuse ..... actually, I wish now I'd autotested BEFORE rallying as it's helped no end! Although, I suppose the gravel forestry tracks are a great introduction to driving. Suppose I can't say at the tender age of -10 years from the legal driving age - coz there's plenty on here who'll whinge ;)
rachmacb

This thread was discussed between 21/03/2011 and 23/03/2011

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