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Conversion Headlamps replace your original manufacture's headlamps, and not only give superior lighting, but also flexibility in the amount of lighting to be used.
Hella, a German company, and Cibie' a French company still makes these for sale. The last ones I bought the dealer is no longer in business. However at the time of this update Carolina Classic Trucks had them inexpensively, or they are available from Ken Beard at Susquehana Motorsports. Moss Motors sells a British version made by Wipac (162-725), but I prefer the German made Hellas.
These lights replace your standard headlights, but provide a much better pattern (see below). As you can see this pattern is strongly cutoff to the left and top. This means that more light is placed on the road where you need it, not in oncoming driver's eyes, and not in illuminating the tree tops. This also means that you can run with higher than normal (55W/65W) and actually your headlights show less glare to the oncoming traffic, and anyone you may be following.
Conversion headlamps come in Single Round, Single Square, and also for four headlight installations, so the pattern may vary slightly from the illustration, but it won't vary much. There are four advantages with using conversion headlights over standard or replacement headlights.
Thus you may want to opt for conversion headlights instead of fog and driving lights, which tend to get broken during parking, and in my opinion spoil the look of the B. Both my TD and B sport conversions, but only the TD has fog/driving lights because I like that look. The major disadvantage is that they are not sealed. Cibie' made a conversion headlight using bulb within the bottle technology (they called it BOBI), but I haven't seen them for a few years. Not being sealed means moisture can get into the headlamp assembly itself. However by ensuring that you install the headlamps according to instructions by placing the vent in the proper orientation so that any accumulated moisture will be dissipated, they are as trouble free as any sealed beam I know of. The other disadvantage is that you can not touch the glass envelope of the bulb which at times leads to some awkward contortions.
The single 7" headlamp per side such as the MGB and MG T series use a dual filament bulb of type H4. Normal auto headlights are 55W/65W, that's 55 Watts on low beam, and 65 Watts on high beam. Normally these headlamps come with a 55W/65W standard white H4 bulb, and will install without modification. However you are not limited to using a 55W/65W H4 bulb. There are several choices available up to and including 100W/145W which is twice the output of a standard light. There is a catch to using anything greater than 55W/65W H4's.
If you check your wiring, your headlamps are wired with about 18 AWG wire and at 65W will draw about 5 Amps. If you were to put in 90W/130W or even 80W/90W the lamps will be drawing between 7 Amps and 10 Amps each. Most standard lighting cannot handle this current, and you will most likely fry your headlamp wiring. To prevent this, you can add an auxiliary harness.
An auxiliary harness is simply an additional harness wired with relays. There is a plug for each headlamp, a wire for ground, a wire that connects directly to the battery, a relay box, and one extra plug, which is a male end and looks like one of your headlamp connections. Its function is to switch the relays appropriately. To install the harness, simply route the wiring to each of your headlamps (see the footnote concerning routing on the MGB). I installed a PIA harness on the MGB, but they are no longer available from PIA, however, Competition Limited does sell one, though I have not used Gene's harnesses, so YMMV (your mileage may vary ) I installed my harness in about 3-4 hours on the B, normal installations in other automobiles can take only 30 minutes, but then you don't have to fool with those buckets.
You may also want to select another color. In France headlights give off a yellow color. QI bulbs come in amber, or the lenses may be dyed yellow or a special yellow glass (remember how hot these get) sleeve fits over the bulb. Either technique reduces the light output by 30%. PIAA sells an H4 bulb called their ion crystal bulb which produces a yellow light, but only reduces the light output by about 5%, they are expensive and sell for about $30 per bulb. (Note: PIAA does not list its ion crystal bulbs on its web site, but they are still for a limited time in the supply chain). More popular now are the very blue white bulbs that look much the same as the expensive Xenon Discharge Lights available on the late model high-end German Vehicles. BTW, these bulbs are also available in 9000 series for your daily driver if you would like -- the same precautions apply and consider the heat output on the polycarbonate lenses modern cars use. The human eye is more sensitive to yellow light, but even with only a 5% reduction in light output, you loose more than you gain with yellow lighting. Where yellow lighting is useful is during winter, where the white snow cover will reflect back enough light that you can lose definition between the snow covered road surface, and the shoulder. However, in these conditions I prefer an alternative. If you don't plan on driving in the snow, then stick to the whites or blue whites. These special coated bulbs are expensive (about PIAA =$35 each, Competition Limited = $16 each as opposed to vs $9 for a standard H4) but they can last for years.
Remember to adjust you lights to manufacturers specifications to make effective use of this improved lighting.
One last modification can be made to your conversion lights if you want to max out every available photon. When you switch your high beams on the low beam filament is switched off, so you can see further down the road but close in is not as well lit. By adding an inexpensive relay (under $5), available at most auto supply stores, you can light the low beam filaments at the same time. This hook up is shown in a word document schematic diagram. Click here to download. Note in the schematic provided, that there is an auxiliary fuse in this circuit since your normal fuses will not protect your low beam wiring using this set up. One note of caution, this does put an additional load on your electrical system, dynamo/alternator, and regulator, ensure that they are capable of handling rated power prior to attempting this mod. Do not skip installation of the relay, as the dip switch contacts will not handle the power.
Last modified: April 26, 2005
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