Light Tech

[C9]

Light Tech


Here's something that may be of interest to those of you who run early cars with early taillights.
A pair of 39's in this case, but we'll also take a quick look at the ever popular 50 Pontiac lights.

What you'll see is some direct comparisons to the old faithful #1157 bulb as well as candlepower listed for each bulb tested.
I probably should have taken some amp readings, but Candlepower (CP) will tell you pretty much the same thing.

All incandescent non-Halogen light bulbs were purchased at WalMart.
Which, translated, means you can get them at most places that sell auto oriented bulbs.

All CP readings were taken from 5" away in an attempt to preclude ambient light from having an affect.
All CP readings were on the taillight circuit.
CP read was directly from the bulb with the red lense removed.

Voltage for the lights was sourced from my pickup parked nearby.
It's a 2002 Ford F150 SuperCrew and has a large capacity battery.
Along with that, the taillights on the 31 were fed with 8' of 14 gage wire which comes close to approximating the typical taillight wire length and size in most hot rods.

Voltages noted with each photo pair were taken with a digital voltmeter connected to where the taillight wiring was connected to the source wiring.
An 8' long single 14 gage ground wire was run and connected to the right side taillight body.
The 31's body is primered steel fwiw.
As is obvious, the taillights and stoplights would have been 5% - 8% brighter if the engine was running, but voltages with the engine off were fairly close so test indications compare favorably with one another.

Before we get too far along, a comment on what some vendors call "Bright Bulbs."
It would be interesting to see what these actually are, but imo they're nothing more than a bulb designed and manufactured to reach it's rated maximum brilliance at a lower voltage than the usual auto combo taillight/stoplight bulb.
Bulbs that fit a particular socket or receptacle are manufactured in many different voltage ratings.

When I worked at the power company it was common for newbies to stick a 24 volt bulb into a 48 volt socket.
The results were always interesting, either a bright flash or a growing brilliance for 2-3 seconds until the bulb blew it's filament.
Other way round, a 48 volt bulb in a 24 volt socket would barely glow.
When a slightly lower voltage bulb was installed into a higher voltage socket, light bulb brilliance was sufficient and they lasted a long, long time.
The bulbs of differing voltage ratings were used as indicator lights so a loss in brilliance didn't
affect things too much.
It would be interesting to see just how long Bright Bulbs last.
Imo, not as long as a standard bulb.

Want a house incandescent bulb that'll last a long time?
Buy bulbs rated at 130 volts instead of the more common 120 volt bulbs.
Available at Home Despair and like places.


The garage - where the pics were taken - has all lights off and it's somewhat dim in there.
In other words, not quite as bright as shown in the pics due to the camera tries to make up for the lack of light.
The camera - a small digi-cam by Canon, Model #A540 - had the flash turned off for all pics.
Sorta like early dusk in the garage in a manner of speaking.

This first photo shows four of the lights we'll be testing.
Set up in a home-made fixture.
I thought we'd get some good comparisons here, but in the pic all the bulbs look about the same.
All bulbs on the taillight circuit.
Bulbs used (left to right) 1157, 1157LL, 2057 & 2357LL
I believe the LL stands for Long Life.



Photo #2 showing three bulbs - also on the taillight circuit - are (left to right) 1157, P21-5W & a 5 watt Halogen.
The Halogen bulb available at Bob Drake re-pro parts.
It's a well made unit and will stand a bit of handling compared to some of the fragile looking double Halogen bulbs on one base.
Like always, if you want the Halogen bulbs to last, don't touch them with your bare fingers.
Latex gloves seem to work well and the original pair of Bob Drake Halogens I had in the 32 lasted 3-4 years before one of them failed.


As you can see, the Halogen bulb throws a lot of light.
Seen in the pic and also seen in CP readings . . . more on that in a bit.


The photos will be self-explanatory to an extent.
Additional things listed will be bulb type, CP (CandlePower) and voltage.

Keep in mind the left taillight will be the one with differing bulbs.
The right taillight will run a standard #1157 bulb as supplied by Bob Drake who also supplied the 39 taillights . . . which are very nice lights.

The first photo of the pairs posted will be taillights and the second photo will show the stoplights.


This first pic in the series has a P21-5W bulb installed.
Voltage = 11.94
CP = 10





Photo pair #2, 2357LL bulb installed.
Voltage = 12.34
CP = 9





Photo pair #3, 2057 bulb installed.
Voltage = 12.26
CP = 5





Photo pair #4, 1157LL bulb installed.
Voltage = 12.24
CP = 6





Photo pair #5, Halogen bulb installed.
Voltage = 12.02
CP = 70 - not a misprint, 70 is the CP.





Photo pair #6, 1157 bulb installed, a match both brand-wise and age-wise to the 1157 bulb in the right side taillight.
Voltage = 12.27V
CP = 9






Here's a small bonus to see how the popular 50 Pontiac taillight compares to the 39.
Visual only, no voltage or CP readings were taken.
I did this test because my pal's full fendered 29 roadster with Pontiac taillights - with blue dots to boot - look brighter than the 39 taillights in my 32.
And in fact I bought a pair of Pontiac taillights - sans blue dots - with the thought that I'd have a nice bright taillight.

I was surprised to see the Pontiac taillights were about the same size as the 39's and brightness seemed the same.
Both the Pontiac and 39 taillights in these photos have black painted buckets.

To top it off, my pal's (equipped with the original 1157 bulbs) has a black painted bucket as well.
My 32 has a bright silver painted bucket.
Paint used was "Chrome" as noted on the label and it's pretty reflective.
Even so, Digger Dave ran some tests some time back and reported that white paint has the best reflectivity as measured by his light meter.
It'll be white paint for me whenever I can get to it.

Here's the Pontiac vs the 39 taillight.





Most of you probably know this, but when you buy re-pro Dietz or King Bee headlights as utilized by A's, 32's etc. they usually come with a standard seal beam light.
For about $9. you can get a Halogen sealed beam at WalMart that's a direct easy to bolt in replacement.
Same plug etc.
The difference in light between the two styles is flat amazing.      


I learned a few things about light bulbs during this little investigation.
Some bulbs do better than others, but the Halogen bulb is the hands down winner.
I understand the Halogen bulb pulls 5 amps and the standard 1157 pulls 1 amp on the taillight circuit.
Fuse your system accordingly.
Use adequate size wiring as well, 14 gage should do it for most of us.

One thing I think would help extend the life of the Halogen bulbs would be to vent the taillight housing.
Early car housings are quite small compared to the large taillight housings found on modern cars and heat doesn't dissipate as fast as it should.
To that end some kind of filtered air exchange device would help to extend the life of the Halogen bulbs.
Filtered to keep dust out of the housing.
If dust is allowed in, the taillight's light output will be diminished.
Lots of ways to do it so I'll leave that part to your imagination.


Over the years I've seen some beautiful cars that were equipped with too-small taillights.
Sorta asking for it to an extent.
It behooves us to use as bright a light as possible and as large as is aesthetically pleasing.
The cars we run are usually small, many times with dark non-reflective - read flat - paint and they're difficult to see.

The third stoplight is a viable option and a good idea imo.
I have one, rather ugly and billety, but I think it's saved the day more than a few times.

A good looking third stoplight is easy to set up so it's bright and blends in with the lines of the car.

More on that another time....

[tomslik]

C(, how much heat does the halogen bulbs make?
i melted the lenses (no kidding) out of my coupe one year at pueblo...

[Dave]

C(, how much heat does the halogen bulbs make?
i melted the lenses (no kidding) out of my coupe one year at pueblo...

I did that on my old 29 a.. Got smart and got glass lenses..
Dave

[Inprimer]

Just rewired my son's 52 F1 tail lites, ,  I took the time to paint the inside of the housing with white appliance epoxy, seem to give off better reflection that the silver paint I tried, so fwiw take the time, its well worth it

[C9]

C(, how much heat does the halogen bulbs make?
i melted the lenses (no kidding) out of my coupe one year at pueblo...

Quite a bit.
Especially when both taillight and stoplight filaments are energized.
I'm not surprised a plastic lense would fail due to heat when exposed to a Halogen bulb in a small light housing.

My 32 has glass lenses so it wasn't a problem.
Even so, the housing ought to be vented for Halogen bulbs.

From what I understand, Halogens draw about 5 watts compared to 1 watt for an 1157 bulb so there's definitely more heat.

It took longer for the Halogen bulb to cool down so I could remove it than the standard bulbs did.

I still have the 'test' stand set up, if I can remember I'll get some amp reads on the Halogen and an 1157 bulb this afternoon and post them.

As an interesting side issue, I have some older 39 glass lenses and they have differing levels of red dye in them.
Some are very dark and a couple are very light.
Re-pro glass lenses made today have equivalent amounts of dye -or whatever it is that makes em red - and are pretty much the same from light to light.

An interesting article I read about some years back is that blue glass lenses like police bikes use would work well for taillights.
They transmit light almost as well as red lenses do as far as visibility and distance go.
The thinking behind the article was that we should run blue taillights and red stoplights.
A reasonable thought, but with the laws on the books now as well as re-training the public it'll probably never happen.

[UGLY OLDS]

Very informative  :!:    :!:    Thank you for taking the time to research  & post this    

[ProEnfo]

Light Tech
Here's something that may be of interest to those of you who run early cars with early taillights.

Thanks, great info.... I run a set of extremely small tail lights,  I've been through the melted lens and LED bulbs and finally turned the bezels on the lath to accept some swapmeet glass lens, looks like it's time to figure out how to vent them.

CC