T-3 Headlamp identification

[Larry T.]

I have 5 T-3 headlamps that appear the correct vintage and OEM for my 1966 car. How can I tell if they are reproduction or original? I do not see any DOT markings. If you have a picture of a reproduction I would like to see it.

Thanks,

Larry

[Jeffrey S.]

Re: T-3 Headlamp identification

Larry:
If the back of the bulb is not smooth and shiny like a mirror but is textured, it is a reproduction. The repros are made by Wagner and their bulbs are textured in back. Originals are smooth.
Jeff

[Philip A.]

Re: T-3 Headlamp identification

Larry
I have also noticed that there is a casting flaw/imperfection in the face of the glass of reproductions, on the clear section, that is not on originals. If you look at a set of repro's you will see it on everyone in exactly the same position.
Phil

[Larry T.]

Re: T-3 Headlamp identification

Then I have five originals. Three with a number 1 on top and two with a number 2. Which are brights, the number 2's I assume?

I have not plugged them in yet, but the filiments look intact looking in. I guess that is a good sign. Are originals in working order hard to come by? I assume the prior owner put in replacements (non T-3's in this case) to preserve these originals.

[Jack H.]

Re: T-3 Headlamp identification

The #1 and #2 designation refers to the number of filaments in the lamp. High beams had only one mode, so they have only two terminals on the back and a single filament. Simple to remember...

[Jack H.]

Re: T-3 Headlamp identification

Also check to make sure they're '60L-67 vs. '58-60E style Guide T3's. The early style lamps are getting pretty HARD to find and the straight axle guys want/need them.

Don't know the difference? Read you copy of the JG book and pay CLOSE attention to its description of the geometry of the T3 center triangle with respect to the positioning of the emboss 'GUIDE'...

[Pat M.]

Re: T-3 Headlamp identification

Another difference is that repos have a tiny DOT mark. See the picture below, second-to-bottom line of square segments, 2nd (or third) square from left.

I also noticed that repos use a blue-colored lacquer to seal the back prongs, whereas originals used an amber-colored lacquer.

[Harry S.]

Re: T-3 Headlamp identification

Some Doc. to look at........

[Larry T.]

Re: T-3 Headlamp identification

I definately have 3 high beam and two low beam lamps. One has a stamp from 1966. Three of them I can see the ink residue from the stamps but nothing is legible.

The last one, a low beam lamp is a little unusual because the line in the middle of the big T is rounded at the ends and the "T" and "3" look a little different. This is also the one that I can see no trace of the stamp. But it also has no DOT markings that I can see. Also the markings near the terminals are different. The first four lamps have two sets of numbers near the terminals, this one has one set of numbers and what looks like an anchor. Any thoughts on this one? See the pictures.

[Harmon C.]

Re: T-3 Headlamp identification

I have burned out lots of thease old bulbs testing them with a full charge battery. I would test them at the plug on the car it may not help but is better than smoking all of them. I would also put silicone sealant between the base of the brass prong at the glass before testing. Jeff S is the sealed beam guy so he may have more tricks to save old bulbs.

[Jeffrey S.]

Re: T-3 Headlamp identification

Larry:
These appear from your pictures to be original bulbs. A I said in the post above, all reproductions are made by one source, Wagner, for one licensed customer. In addition to the DOT they all have the textured back. These are smooth.
Jeff

[Pat M.]

Re: T-3 Headlamp identification

I have burned out lots of thease old bulbs testing them with a full charge battery. I would test them at the plug on the car it may not help but is better than smoking all of them. I would also put silicone sealant between the base of the brass prong at the glass before testing.

Someone in the archives suggested using a 9v battery when testing the lights for the first time, which sounds like a good idea.

I used epoxy to seal the base of the prongs and the end of the little glass tube, and it seems to make a good, tough seal.

[Jeffrey S.]

Re: T-3 Headlamp identification

I'm not sure I understand why it is beneficial to test with a 9 volt instead of a 12 volt. A bulb fails for 2 reasons. One, the filament(s) burn out. Two, the seals fail and oxygen enters the bulb replacing the argon put in at the factory. This causes the twirling column of smoke which eventually fills the bulb. Either of these will happen when any voltage is applied to the bulb and it lights. Once in the car up to 14 volts is applied to the bulb. If you are assuming that 9 volts won't cause a failure but 12 volts will, the second you turn the lights on in the car the bulb will fail. To me it's like testing a bridge with 3/4 of the expected weight and hoping that when traffic goes over it it won't collapse. I test all my bulbs with 12 volts (with the seller's permission) at the time of purchase, again with 12 volts when cleaning and, finally, at the point of sale so the customer knows they work. I want to know that in a real world situation these bulbs will not fail (at least not right away). Sealing the back terminals could never hurt but I have never done that. If they have remained air tight for 50 years then I think that the seals are pretty good. Just my opinion.
Jeff

[Gerald C.]

Re: T-3 Headlamp identification

I have 5 original T-3 headlamps with a smooth back. 1 set of 4001 and 4002 are for 1968-1971. 1 bulb has # 1 on the bulb glass and that's for 1960-1967. Another one has a # 2 on the bulb and it is for a 1968-1971 and finally one has a # 1 on the bulb and it is for 1960-1967. I checked these out by the guide in the Fall 1979 Restorer. They all work and are very bright.

Does anyone have an idea as to the value of these?

Thanks

Jerry