Clear Vision: H4 Headlamp Conversion
Whether you drive a classic truck, muscle-era Chevelle, or a Chevy Citation, good quality headlamps are a must. Most of us have new daily drivers, these cars often have HID (High-Intensity Discharge) and use far better technology to light your path, making your evening drive safer. The classics we enjoy owning and driving, on the other hand, use outdated, less efficient lighting, otherwise known as sealed beam lamps.
Traditional sealed beam headlamps, with heavy glass housings and sealed elements inside the lamp, have long been the staple (required in the US until 1983) of practically every car made from the 1940’s through the late 1980s. When the composite halogen headlamp began showing up in American-built autos in the mid-1980s, the results were a simple and cheap replacement, only requiring the bulb to be removed and replaced, not the entire assembly. As time moved on, the technology of the bulbs increased as well, in 1996, the first HID or High-Intensity Discharge bulbs were introduced. These brighter bulbs illuminate the road much further and wider than standard halogen bulbs, and are far better than sealed-beam headlights.
While Halogen is the main gas used in OE and replacement bulbs, for most cars, there are some more exotic gasses available. Xenon, for instance, burns brighter, giving off a “white” light versus the classic pale yellow light from halogen. Also known as HID-style, these bulbs cost a little more, but are superior to Halogen in terms of visibility. Krypton is another gas that is commonly found in bulbs. The main benefit of Halogen is that it can actually bond with burnt filament molecules inside the bulb and redeposit them onto the filament, which adds life to the bulb. Most Xenon and Krypton bulbs use Halogen, as well as the base gas, for longevity. Xenon\Krypton bulbs have a lifespan of 5-10 years.
Transferring this technology to older cars is really quite simple, as long as you take the time to make the conversion properly. Pilot Automotive manufactures H4 conversions for sealed beam headlamps. These plastic housings are lighter, more durable, and come in various shapes and sizes to fit most older vehicles, the most common being the round 5 1\2” version, though we needed 7” units for our ’67 C10 truck. These housings are a direct replacement for the sealed beam housings. This opens the options for bulbs, which can be standard H4 halogen bulbs, and are a little brighter than the sealed beam lamps which can be run using the stock wiring.
Unless you are going to use standard H4 halogen bulbs, you will need to supply extra amperage to the bulbs. This is a crucial step for using Xenon\Krypton or anything other than STOCK replacement style Halogen bulbs, but it is highly suggested that you update the wiring regardless of the style of bulb you use. While you could sort out the relays, plugs and build your own harness, Painless Performance has already done the hard work for you. Their H4 conversion harness plugs into the stock plug (GM square style, our truck had the round plugs), 2 wires run to the battery and it has 2 plugs for the headlights. The kit uses 2 relays and larger gauge wire to safely supply the bulbs with the higher amperage they require. If you plugged in a high-output bulb, the stock wires will literally melt and can burn down the entire car (it happens quite often). Replacing the stock wiring with this harness will increase the brightness of the stock-style lamps as well.
We replaced the stock sealed beam head lamps with Pilot H4 conversion, Pilot Hyper-White Xenon HID-style bulbs and the Painless wiring kit in our 1971 Buick GS convertible. While not a true HID system, which requires a ballast to supply the higher voltages (and costs a hefty sum), HID-style bulbs offer the look and near the performance in a simple system. The results were pretty impressive, the lights are brighter and shine with an intense white light that really illuminates the road. We also opted for the “Angel Eyes” housings, which is a lit ring around the lamp, similar to modern European cars. While not for everybody, angel eyes add a unique look and in our case, really add a trick feature for the truck as we wired the angel eyes to the turn signals. The housings we used cost anywhere from $50 on the internet to as much as $95 in our local parts store, the bulbs are similar, with the internet price of about $40 bucks, to about $60 in stores.
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