I replaced the ones in my red '69 with halogen (H-4?) bulbs. J.C. Whitney has them. It's a replacement lense that the halogen lamp plugs into. Actually the ones I used are off an road style so they are bright. Opel GT Source aslo carries them.
While you have the headlight out. I strongly reccommend that you look closely at the condition of the wire at the plug. Opel used a rubber insulation that dries out and cracks from the headlight rotation this causes all kinds of electrical problems and short circuits. Add to that the fact that the headlights are not fused and........
I've seen a lot of these H-4 replacment headlight replacements on ebay look under rx7, 78-85 will fit all opels except mantas. The info stated that rewiring must be done if you do not currently have H-4 bulbs, what modifications were needed?
well im ordering them off a website and they say there made to replace a 7 inch round headlight bulb and that there actual size is 7.5 inches so i mean if i rember right the headlights on the gts are about 7 inches or so. im jus gonna order um and i can always return um and get my money back.
pvcar, you can find H-4 lights that are direct replacements at most auto parts stores. I found mine at Advance Auto here. I don't know if you have them there. Maybe a Pep Boys or something like that. They were modestly priced too. Jarrell
It sure is easy to separate out the old folks from the youngsters on this topic. Once upon a time in North America (AFTER the dinosaurs roamed the earth, in the 50's, 60's and 70's) all cars sold here either had four 5 inch sealed beam bulbs (two low beam, two high beam, like the Manta) or two 7 inch sealed beam bulbs (like the GT, Kadett and Ascona). No other types or sizes were allowed by law. And they HAD to be sealed beam style, so aerodynamic Euro headlights with separate bulbs had to replaced with the N/A standard before they could be imported. Period.
In the 70's, aftermarket lights became available that replaced the sealed beam bulb with a "Euro" type that had a lens and reflector that simply fit in place of the sealed beam, and used a replaceable bulb (the H4 as mentioned above for the high beam and 7 inch lights). So when you go down to your local auto store, just ask for a set of 7 inch H4 lights. The most popular brands used to be Lucas (Carello, I believe) and Cibie, but I believe there are still a few aftermarket makers that still make the 7 inch H4 lights. I had a set on my GT, and plan on getting another set (they were terrific, but the reflectors rusted, which is one reason the lawmakers didn't like them)
CIBIE made a 7" H-4 powered headlight replacement called the "Z" beam. I have a set in my GT and in my Sportwagon. I'll never go back to regular sealed beams again. I'm currently trying to get another set of Z beams for my wife's Sportwagon.
Here's the ones I use in all my Opels. Excellent lighting on low beam, very wide, yet won't blind oncoming driver. Also available with standard 60/55W ($1 less) and 130/90W ($2 more) H-4 bulbs, but I like these 100/80W units the best.
BTW, the early US DOT approved sealed-beam lighting size was 7" for two light systems and 5.75" for four light systems, outers were hi/lo beams, inners were hi-beam only.