Correct installation of double filament headlight bulbs

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Model T Ford Forum: Forum 2015: Correct installation of double filament headlight bulbs
Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Patrick on Tuesday, May 12, 2015 - 01:24 am:

I recently discovered that I had 12V light bulbs in my '26 Coupe with a 6v system and replaced them with (2) 6V 50/32CP bulbs. Problem is that I can't be sure if I have them in correctly as the 50CP and 32CP filaments are not marked, so I am unable to figure out which is the bright and which is the dim, for there seems to be no difference in the reading on the ammeter, no matter which way I hook them up and I am unable to tell a difference at night when I turn the headlights on dim and bright. Every possible combination indicates a -10 amps draw on the ammeter. Sure would have been nice if they had thought to label the filaments 50cp and 32cp. Has anyone come up with a trick on how to be sure both bulbs are installed so that they are both on brights whenever the switch is turned to bright and vice versa? The wiring was installed using Ron Patterson's plan and I have double checked it and it is correct. Thank you. Jim Patrick




Top of pagePrevious messageNext messageBottom of page Link to this message  By Dave Young in Mays Landing, NJ on Tuesday, May 12, 2015 - 06:52 am:

The last time I messed with my headlight bulbs, I used a welding helmet to look directly at the bulb filaments, with power to them, and was able to determine which way to rotate the bulb to make the left side match the right side. You need a #10 shade welding lens to do it.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bob Benedict, Hunboldt, TN on Tuesday, May 12, 2015 - 08:27 am:

I found that unless you rotate the entire socket in the headlight bucket, it makes no difference which way you put the bulb in. My original buckets located the bulb's filaments in a vertical position instead of a horizontal position. I had to cut new grooves in the bucket cups that hold the bulb sockets and drill new holes for the adjustment screws. once this is done it is easy to see high and low beams on a wall. I thank God daily for the man that invented the Dremel. Take your time, It's worth the effort. Bob 26 coupe


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Zibell, Huntsville, AL on Tuesday, May 12, 2015 - 08:42 am:

We (Bill Robinson and I) have found that the socket can be removed, the installed with the groove up. We drive the socket to the rear using a spring busing driver, then it can be easily pulled back. It is rotated 90 degrees then re-installed with some blue loctite. I made a fixture to drill the second hole 90 degrees from the original and the correct distance from the socket. That is the only way to get a true high and low with the new bulbs. Also it will require re-focusing to get the correct pattern.


Top of pagePrevious messageNext messageBottom of page Link to this message  By James L. Bodkin - Jim on Tuesday, May 12, 2015 - 09:55 am:

Jim, I have found the same thing. Both filaments are exactly the same!. I forget the exact current draw, but they are exactly the same. Not really 32/50cp. I think the 90 degree rotation is the answer.

Jim


Top of pagePrevious messageNext messageBottom of page Link to this message  By JohnH on Tuesday, May 12, 2015 - 08:37 pm:

If they're the same repro bulbs (bought around 13yrs ago) I've got, there's no difference in the filaments. All that happens is the beam is shifted slightly because of the filament position relative to the reflector. Even then you really have to look to notice it. The original bulbs in my car were 21CP for both filaments and the supposed 32/50CP replacements are not noticeably brighter.
I was given a whole lot of modern "18W" 12V festoon bulbs. They looked rather dim, although the filament temperature was white enough. When I measured the current, they were closer to 6W.
Don't always believe the ratings it would seem.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Larry Smith on Wednesday, May 13, 2015 - 10:58 am:

The original bulbs were 2-21cp. That is what I use. I'm not sure what the bulb number is though.


Top of pagePrevious messageNext messageBottom of page Link to this message  By James L. Bodkin - Jim on Wednesday, May 13, 2015 - 12:15 pm:

The bulbs I use are from Lang's p/n 6572BX. Supposedly 50-32 cp @6v. Each filament draws approx. 4 amps @ 6v making each filament 24 watts.
There was a thread a year or so ago which dealt with the modification for the 90 degree rotation. I think it was discussed that the filaments in the repro bulbs were 90 degrees off. Filaments should sit horizontally, not vertically.

Jim


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bill Robinson Salty Bottom, AL on Wednesday, May 13, 2015 - 02:25 pm:

If the socket is rotated 90 degrees as Bob Benedict states, and the 50-32 cp @6v bulb is installed correctly, then the now horizontal filaments will provide a high and a low beam because the filaments have differing focal points in the reflector & lens.

Of course this rotation will be useless unless the Ford manual is read regarding the proper method of focusing the headlights to achieve a focused beam.

The process is simple- the night vision achieved will be greatly improved


Top of pagePrevious messageNext messageBottom of page Link to this message  By William L Vanderburg on Wednesday, May 13, 2015 - 05:06 pm:

Why can't the individual(s) replicating the sockets reproduce them correctly in the first place? Just how hard would that be?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bill Harper - Keene, NH on Wednesday, May 13, 2015 - 05:14 pm:

I thought that the sockets are correct and that it is the Bulbs that are wrong- 90 degrees off?!?!


Top of pagePrevious messageNext messageBottom of page Link to this message  By William L Vanderburg on Thursday, May 14, 2015 - 09:29 am:

If the sockets were correct you would not need to rotate them is my understanding


Top of pagePrevious messageNext messageBottom of page Link to this message  By James L. Bodkin - Jim on Thursday, May 14, 2015 - 11:16 am:

It is my understanding that it is the repro bulbs that are wrong.

Jim


Top of pagePrevious messageNext messageBottom of page Link to this message  By Larry Smith on Thursday, May 14, 2015 - 11:21 am:

If the bulb doesn't work, just rotate it 90 degrees. I'm not sure about the reproduction stuff out there. I do know we make the angle plugs used in 15-17 and they are correct. We also make a modified unit for those who have the later headlights.


Top of pagePrevious messageNext messageBottom of page Link to this message  By James L. Bodkin - Jim on Thursday, May 14, 2015 - 11:28 am:

Larry, because of the dual contact positions and the bayonet pin position, the bulb cannot be rotated 90 degrees.

Jim


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Thursday, May 14, 2015 - 11:36 am:

I just install them in either direction. Can't tell the difference and they are so much dimmer than modern lights that I doubt the other motorists would notice a problem either. Anyway, I very rarely drive at night if I can possibly help it because the slow moving vehicle is hard to see from behind. I would have no problem driving at night in a well lit city, but not in the country with high speed traffic whizzing all around me.
Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Gregush Portland Oregon on Thursday, May 14, 2015 - 11:44 am:

I think it would be far easier to make the contact in the socket fit the modern bulb then to get the modern bulb made to fit the socket.


Top of pagePrevious messageNext messageBottom of page Link to this message  By James L. Bodkin - Jim on Thursday, May 14, 2015 - 11:47 am:

Norman, you're right about the lack of brightness! I doubt we would ever have to worry about "blinding an oncoming driver".

Jim


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dave Barker - Dayton, OH on Saturday, May 16, 2015 - 02:35 pm:

I have 1158 bulbs on my 1919 speedster, and am in the process of rotating the sleeve, as suggested above.

Looking at my bulbs, there is a definite difference in the filaments. One filament extends farther into the bulb than the other.

Question: Which filament goes on the bottom and which goes on top?

Here's a photo. You can see the difference in the length of the pairs of stems that hold the two filaments.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dave Barker - Dayton, OH on Saturday, May 16, 2015 - 02:39 pm:

Also, I've found that the filament on the shorter stems is the brighter one. The filament on the longer stems is the dimmer of the two.

Thanks.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Gregush Portland Oregon on Saturday, May 16, 2015 - 02:44 pm:

1158 is a tail light bulb not head light. If you are going to take the time to turn the part in the head light at least get bulbs meant for that use.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Gregush Portland Oregon on Saturday, May 16, 2015 - 02:46 pm:

http://www.mtfca.com/discus/messages/506218/541226.html?1431737930


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dave Barker - Dayton, OH on Saturday, May 16, 2015 - 03:46 pm:

Thanks, Mark. I wasn't aware of that. In the thread you posted the link for, I saw that Larry Smith also uses 1158 bulbs for headlights. At least now I know why I have very little light; wrong bulbs, and wrong filament orientation.

New "correct" bulbs are on their way from Lang's. From the looks of them on Lang's website, there is no difference in the filaments, so they should be able to be installed either way, correct?

Thanks again. It'll be nice to be able to drive at night.


Top of pagePrevious messageNext messageBottom of page Link to this message  By George_Cherry Hill NJ on Saturday, May 16, 2015 - 04:34 pm:

Mark,

FWIW...According to the Mazda Lamp catalog of the era, the 1158 WAS intended for a FORD T headlamp...for use in those jurisdictions (like John R. mentions in his post) where the local laws had a limit on brightness, did not yet want dimmable, yet also apparently wanted standing lights when parked.

The 1158 is a 21/2 CP lamp, so yes, it is quite marginal unless you have good focus and great reflectors on the normal beam, and I'll also bet you can actually tell the difference on the switch setting :-).

On another note...No problem with a 32/32 CP though. Someone PM'd me with a 'why bother if both the same?' The answer is that with the second filament moved over some, it doesn't reflect 'true' and 'right' against the reflector, and the beam WILL scatter in a different direction on the ground and to the one side.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Gregush Portland Oregon on Saturday, May 16, 2015 - 07:26 pm:

In today's world the 1158 is a tail light bulb as is what is shown above. I would bet if you had the 1920's era 1158 listed in that catalog and while both have the same pin arangment and CP rating, it would have had the pointed filaments as many if not all of the headlight bulbs of that era did and a different globe.


Top of pagePrevious messageNext messageBottom of page Link to this message  By James L. Bodkin - Jim on Saturday, May 16, 2015 - 07:40 pm:

Dave, Just be aware that Lang's "correct" bulbs are 32/32cp (not 32/50)which when positioned in the headlight socket, are vertical. The optics of the headlight/reflector is designed for the filaments to sit horizontally, resulting in a high beam (high as in up) and low beam(low as in down) - not "bright" and "dim" As George and John have explained in great detail, an OEM bulb is not so easy to find, or even find the specification for! - state laws. Some may have been 32/32cp, some 21/21cp, and some possibly 21/32cp. I don't think there was a 32/50cp in the day, but I could be wrong
I just got back from Lang's. After speaking with Don and Steve (Steve recently got married - another Ashley in the family) it appears our only solution is to rotate the socket 90 degrees. The repro bulbs sold by the "T" vendors are general purpose bulbs made for different applications - not specifically made for the "T" - and of course the're manufactured "overseas". I even wonder if there is enough separation in the filaments to even make a difference?
I have considered rewiring to make "high beam" light both filaments simultaneously. I realize both headlights on "high" would be drawing 16 amps - alone consuming the full 100 watts John Regan warns us not to exceed! I guess I could drive awhile discharging 8-10 amps. I think I will try this and see if it helps - I'll let you know.. I think the ultimate solution would be a new generation 6V LED with the proper optical charactreistics/focal point etc. Wishful thinking,I know! I tour often with a local "A" club and we do a lot of evening ice cream runs.

Jim


Top of pagePrevious messageNext messageBottom of page Link to this message  By James L. Bodkin - Jim on Saturday, May 16, 2015 - 07:50 pm:

Mark, I noticed today that Lang's 32/50 6V headlight bulbs NOW have the pointed filament. Funny you should mention this. As Hillary would say "what difference does it make"? - or does it make a difference?

jim


Top of pagePrevious messageNext messageBottom of page Link to this message  By William L Vanderburg on Saturday, May 16, 2015 - 08:13 pm:

IF the bulbs are not available to be had correctly, how hard would it be to reconfigure the sockets from the maker to fit the current bulbs? Actually have them come pre-done?


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Zibell, Huntsville, AL on Saturday, May 16, 2015 - 10:38 pm:

Dave Baker, the filament you want for the high beam needs to be the lower filament so the parabolic shoots the light higher.

William V, I tried to modify current sockets to get the correct orientation, can't be done, and to make them that way would require an expensive tooling setup. Also looking at the current path that would be required, I believe it would be easy for the socket to ground out if not precisely made. Since the correct bulbs are not available, it appears that rotating the socket is the best way to achieve a high and low beam.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Gregush Portland Oregon on Saturday, May 16, 2015 - 10:57 pm:

I used the 1915 to 1917 socket on one side, it will put the pins and filament in the correct orientation for the modern headlight bulb. Before the other bulb burns out I will start looking for a replacement for that side.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dave Barker - Dayton, OH on Sunday, May 17, 2015 - 04:30 am:

I'd like to thank George, James, John, William, and Mark for all their experience and wisdom. I've already rotated the sleeves in my headlight buckets 90' as described in the posts above in hopes of getting better headlight performance.

The bulbs I've ordered from Lang's, according to their website and follow-up email, are 6 volt, 50-32 c.p., item number 6572BX.

If these are not actually 50-32 c.p. (James), Lang's needs to inform us of that, as folks are ordering and paying for bulbs that aren't as advertised. I expect to receive what I ordered.

My invoice:

Item Number QT Description Unit Price Extended
6572BX 4 Headlight bulb, 6 VOLT, 50-32 c.p., double contact
Year: 1919-1927 $1.15 each $4.60
A NOTE 0 Customer Backorder Preference: Ship as Available $0.00 $0.00
Subtotal $4.60


Top of pagePrevious messageNext messageBottom of page Link to this message  By John F. Regan on Monday, May 18, 2015 - 04:26 pm:

Others may have already posted on this but your will not get the horizontal tie bar type filament shape to focus very well if at all. The teepee shaped filament is the only one that was used as headlights when focus was actually accomplished. Many years ago Reid Welch did about a month on bulbs as I recall and went through the various issues. His research had nothing to do with HFM research in the archives but I believe the final conclusion was that every bulb that worked per the Ford service book on focusing the bulbs was in fact a teepee shaped filament and the others present too much of a "flood" rather than a "spot" of light and thus no focus. Someone said that the 1158 is now a tail light application and I agree. Interestingly modern bulb makers that were also in business in the day seem to have retained the correct bulb filament and its history while the newer kids on the block are selling bulbs made that probably match the voltage and CP but otherwise are just something made to fit and seem to work but not really a bulb that can be focused. Since very few restorers bother to re-silver the reflectors and those that at least attempt to restore the function of reflectors unfortunately seem to not be aware that chrome is nothing like silver when it comes to reflection so they buy chrome reflectors and the mess just gets more murky. I don't exceed 32CP myself and would add more lights rearward if I were to want things brighter since that is where the danger is. When you get in a wreck you are most likely going to get hit in the butt.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dave Barker - Dayton, OH on Monday, May 18, 2015 - 06:02 pm:

John - Thanks for the information. If we can trust the description and photos on Lang's website, the bulbs I ordered are 6 volt, 50-32 c.p., double contact headlight bulbs. The photo shows the "teepee" filament, so hopefully they are correct. We'll see when they get here.


Top of pagePrevious messageNext messageBottom of page Link to this message  By William L Vanderburg on Wednesday, May 20, 2015 - 04:09 pm:

I probably did something stupid, but what the heck.

I certainly do not advocate doing this...

I bought a NOS box of Westinghouse 1158 bulbs, double filament, 21/3cp. Yes, I know, the originals were 21/2cp, but that's what was available.

There were 10 in the box, box was storage damaged, but the bulbs were OK. Contacts a little corroded, but they cleaned up and they light up. The light is marginal, but you can tell a distinct difference on low and high, where as before you could not.

Interestingly, the sockets DO NOT HAVE TO BE ROTATED. The filaments are correctly positioned at horizontal.

The box was 13 bucks. I think they were made in 1994.


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