Are low beam and high beam headlights different?

[carnut1947]

As we all know my car has 4 headlights. I've installed Cibie style H4 headlights from a mid eighties Jaguar in the low beam buckets. These were used as high beams in the Jag. Is there a difference in the lens configuration regarding how the light is dispersed?

[alpinacsi]

Yes.

Are you sure they were correct in the Jag?

[dcains]

On most of the Euro-market cars the low beams and high beams both used H1 bulbs (single filament), although the beam pattern between the two housings was very different. The lows had very sharp horizontal cut-off in the beam pattern, to avoid blinding on coming drivers, but the high beam was more of a flood or long-range spot beam (dependent on the brand and type). On high beams, all four lamps came on, with both the low and high beam patterns lighting the road.

Conversion headlights for the US market had H4 (dual filament) in the low beam and H1 (single filament) in the high beam, because that was what the sealed beams they replaced had. The low beam patterns were the same as the Euro, but when you switched on the high beams, all four lights came on, in the high beam pattern (again, same as Euro), but the low beam filaments (and beam pattern) were off. because of this, illumination of the road may be slightly lacking immediately in front of the car, but the high beams might be a bit better.

Some say, that the H4 design is a compromise, because you're asking one lamp to produce both beam patterns, but in actual use, I haven't seen much t complain about, and I've had all the various brands and combinations on various cars for the last 40 years or so. It may be that someone improperly adapted the H4 in all 4 positions in your Jag, and that probably worked OK, if they were wired appropriately (and the low beam filament in the high beams wasn't powered).

For your E24, if you need a set of high beams, find a set of H1 high beam housings from Hella, Cibie, Bosch, etc. Probably have to spend $100 to $120 for a new pair. Avoid the cheap eBay knock-off Chinese-made crap, and use high-quality German-made bulbs from Philips, Osram, Varta, etc.

[carnut1947]

I've done some further investigations. My lamp says H4 E1 So its lens is set up for a dual filament bulb. correct? So it appears it was in the wrong bucket in the Jag. The other numbers seem to point to a dual filament lamp as well. 24526R20. Could someone verify this? DCAINS you seem to be the most knowledgeable.

[dcains]

The 24526R20 is a Hella high-low lamp and it takes a dual filament H4 bulb. The E1 tells us it is a Euro code light, while a US lamp would have DOT on it somewhere. It should only be mounted in the outer headlight position, but could have been in an inner high beam position and maybe the wiring harness was hacked?

[carnut1947]

Thank you! So I have the right type of lamp in the correct bucket. Eventually I want to replace the US sealed beam high beams as well with H1's to match.