Welcome to our Site for MG, Triumph and Austin-Healey Car Information.


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 Technical - Confused about halogen headlamps

My 74 B has original style headlights.
1) Can I replace them with halogens such as Sylvania
2) Will they make a noticeable difference?
3) Do I need to make any other changes such as a different relay?

Dan Hiltz

Dan, I've been running Halogen headlights on my '67 B for over twenty years and they've made a huge difference in night time visibility. I use sealed beams and they simply plug in to your existing harness terminals. I don't use a relay system, but many people do to take the load off of their headlight switch. The '67 and earlier Bs used a much sturdier switch than the later cars did. RAY
rjm RAY

You will get between 15% and 20% more lif=ght out of the lamps if you use relays due to the lesser voltage drop.

That is an average from doing about 10 systems on different cars.

Remeber 10% extra voltage gives 20% more power.
Eddie Cairns

Dan. Just did this upgrade on my 67 GT. The light difference is very significant. Much better lighting at night.

I did install the relay harness, but I am running an alternator and basically installed the relays for peace of mind as I still have the original wiring in my 67.

Unfortunately, I cannot recommend the Lucas halogen light kit that VB is selling. The wiring harness is not made for the MG, you have to modify it. The cans are not the same as the originals, the retaining ring did not fit the cans, and the original chrome rings also would not fit on the cans.

The good news, is you really can just get the halogen lights and they will replace the existing sealed beams perfectly. Both VB and Moss sell just the light and bulb.
Bruce TD4139 Cunha

The best ones I have found by far are the Cibie lamps made by Valeo. I know this link is for the UK, but it shows what I have bought Maybe you can source them in the USA.

They take a standard H4 halogen bulb which plugs in without any modification to the existing wiring. They come for right or left hand drive, with or without the sidelamp inside. The beam control is superb and the overall improvement is such that you will never go back. My MGBs headlamps are better than on our modern VW. I have found them far superior to the common Wipac halogen lamps.
Mike Howlett

Putting relays as close to the lamps as possible, reduces losses caused by cable length, bullet connectors and the switch contacts. Alone that makes a noticeable difference, then using high output halogens will make the light output stunning.
Allan Reeling

Agreed, although I would never put relays in front of the radiator. I fitted them and fuses (one for each filament) behind the radiator where they are protected from the weather. On another car I had a relay spade corrode through from being mounted on the slam panel.
Paul Hunt

Thanks for the feedback. Will any 30 Amp, 12V relay work or do I need something else?
Dan Hiltz

Standard 4 pin relays.
Allan Reeling

Apparently, these Osram Nightbreaker bulbs are also a considerable improvement over standard H4 bulbs.
Dave O'Neill 2

Also apparently, you pay for the brighter light for the same wattage with a shorter life, I've read of annual replacements for a daily driver i.e. on night and morning in winter, as well as in rain at other times.
Paul Hunt

I used the Valeo ones too and put the relays/fuses behind the radiator panel. I got all the fuses, relays, holders, crimps and correct colour wiring from Vehicle Wiring Products up in Derbyshire.

Dave Smith GT

This thread was discussed between 07/05/2015 and 11/05/2015

MG MGB Technical index

This thread is from the archives. Join the live MG MGB Technical BBS now