Jump to content

Aiming headlamps for best performance ‘38 Buick


rodneybeauchamp
 Share

Recommended Posts

Thought I would post here as it applies to all ancient headlamps. They are Guide Multibeam.

 

I have replaced the 6Volt incandescent headlamp globes with a QH replacement which is designed to fit in the original holder. All good and they work. I have put 6V relays on both high and low beam circuits with heavy wire. Seperate earth wire to the socket. The lenses and reflectors are in exceptional condition.

 

I have set the lamps up as per the ‘38 Buick Workshop manual .


Set up on a wall a series of intersecting lines at the centre of each lamp, then on HIGH beam, focus the hot spots for each lamp separately at a distance of 25 feet.

 

OK, am still not satisfied with the performance. They seem bright enough but I don’t think my aiming is right. 
 

Can some of you shed some clues as to what to look for when aiming headlamps. 
 

What makes it difficult is the adjustment screw is difficult to get to (thinking I might make a socket/screwdriver to keep it on the head) 
 

 

Happy to entertain any thoughts or ideas not matter how silly! 😀😀😀😀😀

 

Rodney
 

F6CD9D33-3232-49C2-9D33-73ED669989DB.jpeg

F8E61C51-0B08-4E99-AA3A-401703E4A044.jpeg

Link to comment
Share on other sites

I really have no answer for you but I have been thinking about this situation for my '36 Dodge. Have you actually taken it out on the road at night yet to see where the beams are focused in relation to the roadway. With the new bulbs, I'm sure that you can actually see better than with the old factory bulbs. I would think, and just my opinion, that the left lamp could be tilted slightly downward and to the left to highlight the berm side lines, and I'm assuming that your roads are marked on the centerline and berm sides, similar to the U.S.. The right lamp could be tiled slightly downward and to the right to help illuminate the centerline better and to keep the beam from getting in the eyes of an oncoming driver. If I remember right, most of these old car lamps where  center focused about 3 ft from the floor, which may not give good highway illumination. just some thoughts, but I guess trial and error is probably the best way to get the illumination that is comfortable for you. Good luck and happy motoring!

Link to comment
Share on other sites

Part of the reason for the disappointing performance may be the original aiming procedure was written for the old Mazda low candle power lamps aimed the lamps low enough to get a bulb with low performance to usefully illuminate the road over a short range because that range is limited by the power of the bulbs.  Those low power bulbs had a very short range.  If you aimed them like we do with a contemporary bulb they would not have lit the road sufficiently in front of the car to have been worth running.  Aiming the lamps high enough to extend the range would quickly eliminate visible road definition, would be like trying to shine a flashlight at the moon, the darkness just gobbles up the light and you wouldn't know the flashlight was even turned on. If I understand the new lights you installed they are modern bulbs, reflectors and lenses.  If that is the case you have a best case scenario, higher power bulb in a matching reflector with a modern lens that all work together to optimize the range and reduce scatter.  If you have just replaced the bulbs with high powered units the original reflectors and lenses are probably holding you back.      

 

You might do well to find a piece of flat pavement  with lane lines on it somewhere like a long straight driveway for a closed business and take your car and another car out there, space them 300 feet apart and and facing each other, then adjust the aim of your low beams up until they just start to get annoying for the driver in the other car.  The next test would be to see if the high beams still improve the useful range of the headlight or are they now aimed too high?  If you think they are aimed too high try adjusting the headlight aim down a bit and see if you can find a compromise azimuth adjustment for the high and low beams.   Its going to be  process of trial and error to get the best out of the new bulbs. 

Edited by Str8-8-Dave
edit text (see edit history)
Link to comment
Share on other sites

To answer both of these.

 

1. They are new technology (QH globes) using 1938 reflectors and lenses that are in exceptional condition.

 

2. After aiming them properly and coming back from there at night, both low beam and high beam were better, but not enough to inspire confidence driving at night at 50-55mph on a country road.

 

3. The adjustment screws on both lamps are extremely awkward to access ( but I can resolve that by making up a tool)

 

4. Previously I had been flashed by other drivers because the aiming must have been too high, hence my efforts to get them right. 
 

5. The Buick dip switch is very poorly placed on the floor and I struggle to find it quickly therefore am reluctant to use HIGH beam, but that is something I can address. 

 

I think I will take up the idea to get two vehicles on a two lane road ( or similar) and adjust them high enough without getting too annoying to the oncoming driver.
 

One of the issues may be that the adjustment procedure is done on HIGH beam which assumes that all is good for low beam.

 

As an aside, many years ago I installed a QH globe into a late 50’s semi sealed beam and had the best headlights ever!

 

Will still be interested in other ideas too!

Link to comment
Share on other sites

My way of doing this is get on a dark, preferably little used , road  and if you can, one with trees along it is best, Stand in front of one light and you can clearly see where the other is illuminating. If it is way to high you can see it on the trees. Do this with both high and low beams. Yes, it's a compromise sometimes.

Link to comment
Share on other sites

You might want to check that the relationship between the new style QH globe and the reflector is the same as for the old globe. [ distance from the base of reflector to the filament position in the globe.]

 The reflector and globe holder are designed to position the filament of the globe correctly in relation to the reflector there by collecting and focusing the light generated by the globes filament.

Hope this helps

 

  • Like 1
Link to comment
Share on other sites

8 hours ago, 1930 Kram66 said:

The reflector and globe holder are designed to position the filament of the globe correctly in relation to the reflector

In other words, if the focus point of the reflector does not match the filament location in the new bulbs, factory specs are useless.  

You have bumper mounted driving lights, so why not use them for added range?

  • Like 1
Link to comment
Share on other sites

Agreed;  if the focal length of the new bulbs is different then the original bulb all adjustment will go out the window. 

 

The diagram shows what happens to the light if the bulb focal length is altered.

image.png.3303502478111678f3691bea73e8921a.png

 

I have avoided this by using auxiliary lights with relays, I just shut them off when there is oncoming traffic.  I use stock bulbs with relays on the stock headlights.

  • Like 1
  • Thanks 1
Link to comment
Share on other sites

Definitely do your adjusting on low beam.  On low beam you have to keep the oncoming traffic happy.  On high beam there should be no opposing traffic so the only driver you have to please is-   well-          you...

Edited by Str8-8-Dave
add text (see edit history)
Link to comment
Share on other sites

If the car is in Australia, a right hand drive country, and you have a repair manual from America, a left hand drive country, that could be part of your problem. Do the lights now dip to the left or right? This may need to be seen to.

Have you tried taking the car to a garage and having the headlights adjusted with a modern aiming system?

  • Thanks 1
Link to comment
Share on other sites

Those Buicks have three-beam headlight.  I trust that you've found the two positions of your dash pull switch in headlight mode. The shop manual shows the best method for aiming; even so the beams are kind of wide and not sharply defined on a garage.

 

I've always liked the foot switch to change beams; its something I grew up with going back to the early sixties and a previous '37 Buick.

Link to comment
Share on other sites

OK, a few answers to all.

 

1. the spotlights have LEDs and dull ones so don’t do much. Might change that.

2. headlamps only have 3 positions. OFF PARK HEADLAMPS, none of this fancy passing beam stuff

3. Yes, using a US manual but was reversing the image so the lights would direct to the left.
4. even on LOW beam, light is still ordinary for safe driving.

5. the HIGH/LOW dip switch is on the flat section of the floor by my left heel and is awkward to locate in a hurry.

 

I think I will experiment by trying to aim using LOW beam, not HIGH. Perhaps the factory specs no longer apply now with different globes.

 

Will also try the two cars at 10 paces making sure I’m not blinding the driver.

 

I think I will also try the deserted tree lined road trick but will make up an adjusting screwdriver that is a positive fit on the screw. Currently it is very hit and miss.

 

If I don’t have good result I might retry the original incandescent prefocus globes and see what transpires. Even one side QH the other standard.

 

thank you for the input

Rodney 😀😀😀😀😀😀😀

Link to comment
Share on other sites

7 hours ago, rodneybeauchamp said:

2. headlamps only have 3 positions. OFF PARK HEADLAMPS, none of this fancy passing beam stuff

 

Then most likely your headlamps are completely different too. The "Guide Multibeam" system used both headlights to create the beam pattern. They were aimed crosseyed, and had contoured reflectors and a vertical (yes, vertical) beam cutoff. I really don't see how they could have repurposed these for Australian traffic without making special lenses in reverse, and if they did you would have the 4 position switch.

 

7 hours ago, rodneybeauchamp said:

3. Yes, using a US manual but was reversing the image so the lights would direct to the left.

 

Yeah, I can understand that would not go well. I don't think the US manual is going to do you any good at all. It is going to take either an Australian manual, or maybe you could find information for another Australian car with the same headlamp setup. The markings on the lenses could be a clue. Are they locally made or Guide US? Look for a name on the lens (multibeam, depress beam, twilite, tilt-ray, liberty, guide-ray, twolite, etc.)

 

In rebuilding the headlamps for my 36 Pontiac, I discovered there were some Chevrolets, possibly a different year, that used the same contoured reflectors as my Multibeam system, but had different lenses and dipped High-Low like a more modern car. If lenses like that existed for your 38 Buick, it would have been an easy out for GM to just use them and a more normal headlight switch.

 

7 hours ago, rodneybeauchamp said:

5. the HIGH/LOW dip switch is on the flat section of the floor by my left heel and is awkward to locate in a hurry.

 

Yikes. I don't recall ever seeing one down really low. It was normal in the US to have a left foot switch for dipping clear into the 80s or maybe 90s, but it would be up higher.

 

7 hours ago, rodneybeauchamp said:

I think I will experiment by trying to aim using LOW beam, not HIGH. Perhaps the factory specs no longer apply now with different globes.

 

The factory specs would have to still apply. As others mentioned the filaments have to be in the right position or the light won't project. See if your globes have the filaments in the same position relative to the reflector as the old incandescent ones. That's what matters. Does your car use "American Prefocus" globes like a US Buick does? As far as I know, there is only one source worldwide for QH versions of those, and it is in Australia. I hear they work well. I have been meaning to try them. Let us know how it goes.

Edited by Bloo (see edit history)
Link to comment
Share on other sites

For right hand drive Australia (and New Zealand) GM used the same lens part numbers as USA.

They may not have bothered about it or the lights dipped "down" and not to the "side"

 

Also Rodney's car may not have original reflectors and/or lens on the right and/or left side.

 

https://forums.aaca.org/topic/125491-newbie-with-38-mc-laughlin-limo/

 

Quote

 

Being a right drive car the lens should different to LH drive so to direct light the other way (that is a different part number)

http://en.wikipedia.org/wiki/Left_Hand_Drive#Headlamps_and_other_lighting_equipment

The 1928-1941 Master Parts book pg 33 lists lens as

920491 1937-38-LH

920492 1937-38-RH

923427 1939-LH

923428 1939-RH

My "Catalogue of Genuine GM Holden Parts for Buick" (Australian right hand drive cars) lists

918805 1936 LH

918806 1936 RH

920946 1937

920491 1938 LH

920492 1938 RH

923427 1939 LH

923428 1939 RH

For some reason only one lens is listed for 1937. All others from 1932 to 1939 list LH & RH lens. I suspect this in a error in the catalog and what you have a is a set of 1937 lens.

Using 1937 lens in a 1938 model year car built late 1937, as Dave's post above, probably not that unusual.

 

 

  • Like 1
Link to comment
Share on other sites

Are you sure the bulbs are pre-focused correctly.  I bought a pair of supposedly pre-focused bulbs but they were not.  Much brighter light but not directed.  Second set were as advertised.  If your lights were properly aimed with the original bulbs they should not have needed aiming with new pre focused bulbs.

 

Good Luck and stay safe.

Link to comment
Share on other sites

1. Replaced the original globes with QH without testing the originals as the lights were dreadful. Upgraded wiring, grounds and relays on each circuit. May need to retry them.

 

2. LH lens is Guide Multibeam, RH is a NASCO which is the Genuine replacement part (or could have been fitted as original equipment in Australia)

 

Yellow reflection is the work lamp

 

Rodney 😀😀😀😀😀😀
 

 

 

 

42289F37-67C5-4906-9419-BFFD58378B95.jpeg

D0B258A8-5DF5-4255-951C-6D128B0FA918.jpeg

  • Like 1
Link to comment
Share on other sites

1 hour ago, rodneybeauchamp said:

1. Replaced the original globes with QH without testing the originals as the lights were dreadful. Upgraded wiring, grounds and relays on each circuit. May need to retry them.

 

2. LH lens is Guide Multibeam, RH is a NASCO which is the Genuine replacement part (or could have been fitted as original equipment in Australia)

 

Does the lens have the numbers cast into it?   Many NASCO lens

The AU GM parts book I referenced was issued by NASCO effective July 1939

Does the lens have a thick cork gasket?  May effect the light patterns as the sketch above

 

1923-39 Nasco Catalogue_s.jpg

Edited by 1939_Buick
added image (see edit history)
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...