Sealed Beam Headlights

[Harmon C.]

I found a case of old sealed beam headlights for my own use. I put 12 volts to them off my jump start with a 12 volt battery that I keep on charge. Out of the first four bulbs two smoked and burned white inside.Could this be the wrong way to test them? Is their anything I can do to help my odds of getting more good bulbs out of the other eight I have to test.

Lyle

[Dave S.]

Re: Sealed Beam Headlights

Lyle,
I've been buying them for a long time and a 12 volt test is the only way to go. After all, that is what they will get in the car. Continuity tests are worthless. I learned my lesson many years ago when I bought a case of 12 NOS T-3 lamps at Spring Carlisle. They looked as new and I bought them right. Brought them home and put 12 volts to them. 9 went up in smoke.

[Michael H.]

Re: Sealed Beam Headlights

Lyle,

The problem that occured with your lamps actually started years ago but plugging them in finished the "burn out" phaze. These things are assembled under vacuum conditions and as long as the lamp/glass doesn't leak air, the filement will probably continue functioning. If the glass does leak slightly over several years, the filement burns immediately. When these were in a car years ago, I'm sure they worked but in the years between you finding them and actually testing them, they leaked enough to cause immediate burn. Sad but true. Even happens to NOS T3's.

[Harmon C.]

Re: Sealed Beam Headlights

This case is NOS that is why I stoped testing but I guess I will smoke some more tomorrow.

Lyle

[Mike M.]

Re: Sealed Beam Headlights

mike is right on. oxygen entering the bulb via a poor seal in the vininity of the plug/spades is what kills the nos filaments. if you can rig up a vacuum source to evacuate the atmospheric air from the bulb then seal the area around the plugs(silicone?) , the bulbs/filaments may last for years. doubt linda lovelace would suffice as vacumm source. good luck, mike

[Philip C.]

Dont Smoke em Sell em or give em or trade em

There are guys out there with bow tie cars that could use them, you smoke em their worth nothing or good for nothing, my toughts Phil 8063

[Michael W.]

Re: Dont Smoke em Sell em or give em or trade em

But there again, changing parts on a car to make it look better during Bowtie judging is not right either.

[Joe R.]

Re: Sealed Beam Headlights

I seem to recall seeing a discussion on this same topic a couple years ago on this board. While the consensus was that the failure mechanism was due to the ingress of oxygen and/or moisture, I think that someone involved in the discussion claimed he had a process to gradually "bring up" a bulb that had been stored for years.

His process may have involved applying less than 12 volts for a period of time and then gradually increasing the voltage, or maybe there was some sort of oven baking step. Maybe both.

Sorry, but my memory on this is not clear. In any event, you might want to spend some time searching the archives to try and find that discussion.

I'm not convinced that those methods would really help save a bulb that would otherwise have failed the "sudden 12 volt" test, but if I had a box of bulbs and most were failing the "sudden 12 volt" test, I might be inclined to experiment with a few bulbs.

[Kevin M.]

Re: Sealed Beam Headlights

Reseal the area around the plugs with silicone before testing and try the low voltage method. I think the hot filament sucks in air through a weak seal.

Kevin

[Jimmy J.]

[Harmon C.]

Re: Sealed Beam Headlights

All
Thanks for the replies. I think their was a post about putting them in a oven so the shop light may help it's worth a try. I never have much luck with the search on this board as I get way too many hits.
Lyle

[Joe C.]

Re: Sealed Beam Headlights

Lyle,

Look on the back side of the beams. See where the terminals seal against the glass. The sealant breaks down, gets brittle, shrinks and leaks. If you are lucky enough to test any that have not leaked, then carefully apply RTV to all three seals. That should keep them AOK for a few hundred years.

Joe

[John D.]

Re: Sealed Beam Headlights

Michael, You guys really have me scared now. I got dinged at Marlborough by BG because my drivers side low beam had a tad of black on top. Getting ready to install a NOS one-only have a couple of those but now I will be afraid to lite it up? I know not to test the bulbs with a battery charger. I was always told to test them with a battery instead.I will try and put some slop on the connectors to keep from smoking it up. Maybe pork fat ala Emerald. Maybe I will forget the black spot and take the hit until the old bulb fries itself. At least it lites up and will pass ops and maybe PV. More guys fail ops with bulbs smoking up than anything else. At Marlborough I saw a guy turn his lites on and immediately his low beam smoked and blew out. Felt sorry for him. Maybe repro bulbs are the way to go for sure. They sure do burn bright. Only 3 dings a set isn't bad for sickos like me worrying about points. John

[John H.]

Re: Sealed Beam Headlights

Unless you're into Star/Bowtie, why bother? In Flight judging, repro T-3's are only a 3-point deduction for a full set, they won't die on you in Ops or during a PV, and you can actually see when driving at night.

[Harmon C.]

Re: Sealed Beam Headlights

John
Do they repop the 72 only T-3's or the Power Beams?

Lyle