The bulbs you need are HB3 (9005) 55w, not over 6000 k or you go too blue and attract attention. I got loads of ballasts from previous cars so I just bought the bulbs for about $12 from Guandong.
Access is via the panel over the headlamp unit,

This is not an HB3 but white wire is the same
Remove the power connector and take out the old bulbs and note the direction to undo. Now put in the new bulb with the white wire that runs along the bulb to the bottom shine a light from the front so you can see when you have it aligned with the hole and rotate to lock into place. This is a gynaecological job so the left-hand light is easier and put the hood up in the service position.
Fit the ballast to the bulb but the power connector needs to be fitted the opposite to what you would expect as the polarity is not "standard" on the bulb connector The holding clip will not be engaged but it's tight anyway.If it don't work you got the connector the wrong way . Stuff all the wiring into the access, there is lots of room for it ..then enjoy

 

Just so that we can be clear, the main beam is what the US calls the high beam? You understand why chucking an HID bulb onto the reflector and calling it a day is a bad idea, right?

 

For sake of clarity for all our dedicated readers, you go ahead and inform us.

 

I'll jump in here, because the light scatter is so severe that you blind oncoming traffic and if you lower the beams enough that this doesn't occur the low beam will be pointing to the critters on the roadway. I say this with first hand experience. A projector housing for high beam is the way to go, either led or HID.
wj
BUT!!!...if you drive mostly in rural areas an LED high beam will spread the light which might be good, it does not reach as deeply. Into the distance (percieved based on increased brightness) so high speed country driving is compromised a bit. In the city I see no excuse for blinding everyone with LED high beam bulbs in the factory housing.
ymmv

 

The low beam with an HID bulb is fine and complies with UK regulations. The only requirement for main beam is that it is efficient as there is no one to blind.

 

Wymjym did an excellent job explaining the problem with the optics, but there’s another issue.

High beams are often used for flashing, or for short periods of time. HID bulbs have a slow start up and can take up to 15 minutes to warm up and reach full brightness. This is not ideal for a high beam that is frequently turned off to avoid blinding others. These frequent cycles will damage the bulb in short order as well. This is why HIDs that are see high beam or main beam duties are used in low beam or dipped beam bi-xenon projectors where the cut-off shield is dropped by a solenoid when high or main beam function is requested.

Chucking an HID bulb into a halogen housing for high or main beam use will not only result in inefficient, blinding light scatter that may not even be useful to you, but will also damage the bulb in time. Also, the increased heat could even burn out the reflector after some indeterminate amount of time.


Chucking an HID bulb into the Halogen low beam projector will be less problematic, but, there is a possibility that the halogen projector could result in less than stellar light output with an HID bulb due to the optics of said projector and bulb. However, this varies on a case by case basis. On some cars, the design of the halogen low beam projector is close enough to that of an HID projector that an HID could perform ok in it. In others you may even get reduced light output. No one, as far as I know, has tried this in an XK8 and reported their findings in the forum.

If the filaments of the H1 low beam bulb are in a position close to those of the globe in the HID bulb relative to the base of the bulb, there is a possibility that the projector will perform adequately. If the position is different, bad light output is almost guaranteed.


For the high beam, you would be better off using an HB3 LED bulb or converting to an LED high beam only projector like I did. For the low beam you could attempt to retrofit an HID Bi-xenon projector or do the experiment of installing an H1 HID bulb and reporting back the findings.

Whichever direction you decide upon, please report back to this thread with pictures facing a wall at 30 feet (about 9 meters) showing what the beam pattern looks like (at night) and another picture of what the light output looks like on a dark road.

 

Flashing of headlights in the UK has been made illegal so not bothered about that.
The HID in both units complies with British test requirements so I am happly.
I have one main beam reflector to get re chromed but if that proves too expensive will try the $30 main/dip units.

 

Okay...since this is an international forum it would be nice if there is some sort of clarifying statement prior to making a broad recommendation that might be implemented in other countries where it/they would become an issue.

wj

 

My location is top right ..

 

That is not always so. If replying from a mobile phone, as I usually do, you can't see other people's locations.

Since you are in the UK, make sure the projectors you are being are made for Right Hand Drive cars. The slope of the cut-off shield should be inverted compared to LHD cars. Also, the cut-off style is different between DOT projectors (USA), and ECE projectors (Europe). You should look at that too.