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Old 01-18-2019, 07:00 PM   #1
sphanna
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Default Head light focus with out lens?

I thought if I focused my head lights without the lens to make the smallest and round spot that would be a good way to focus. I did this and with the lens replaced, I think I got a reasonably good patterns as shown in the Ford service bulletins. I am open to advice or critique. Thank you.
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Old 01-18-2019, 07:42 PM   #2
Charlie Stephens
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Default Re: Head light focus with out lens?

When you place a sealed beam bulb behind an original lens it defocuses the beam so there is something going on with the lens. I wouldn't have expected the good result you are reporting.

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Old 01-18-2019, 07:46 PM   #3
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Default Re: Head light focus with out lens?

Sounds good to me. Have any pictures?
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Old 01-18-2019, 08:06 PM   #4
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Default Re: Head light focus with out lens?

Makes great sense to me. I once ended up doing things the other way 'round. I focused the light as best I could, then at some later date (for reasons I don't remember) I had the light apart. I checked the focus without the lens and got a well focused beam as you describe. Comforting!
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Old 01-18-2019, 10:57 PM   #5
Jim/TX/GA
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Default Re: Head light focus with out lens?

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When you place a sealed beam bulb behind an original lens it defocuses the beam so there is something going on with the lens. I wouldn't have expected the good result you are reporting.

Charlie Stephens
You're correct. That's because a sealed beam already has a lens molded into the clear glass front, to put the correct pattern out on the road. Put a second Model A lens in front of that and it's "too much lens". (Kind of like putting in your contact lenses and then putting your regular correction glasses on on top of them. Too much correction. You can't see well.)

This guy is talking about putting a regular bulb in the headlight reflector without a lens and then focusing it. It should work. Remember to focus on the High beam, though. That filament is in the center of the reflector and should focus to a very strong spot beam.

Then you add the lens and it should look good, like in the Service Bulletins (but you may need to loosen the nut on the light and aim it to the correct height).
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Old 01-18-2019, 11:00 PM   #6
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Default Re: Head light focus with out lens?

Charlie Stephen ,. The bulbs were standard incadesent bulbs , not sealed beams
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Old 01-19-2019, 01:19 AM   #7
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Default Re: Head light focus with out lens?

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Charlie Stephen ,. The bulbs were standard incadesent bulbs , not sealed beams
I assumed the ones you were using were standard incandescents. What I am trying to say is that the lens changes the path of the light as evidenced by what happens when you use sealed beams behind original lenses.

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Old 01-19-2019, 04:02 PM   #8
Jim/TX/GA
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Default Re: Head light focus with out lens?

Quote:
Originally Posted by sphanna View Post
I thought if I focused my head lights without the lens to make the smallest and round spot that would be a good way to focus. I did this and with the lens replaced, I think I got a reasonably good patterns as shown in the Ford service bulletins. I am open to advice or critique. Thank you.
Can you post photos of the focussed High beam without the lens, and then with the lens? That would be helpful.

At night, on a wall...

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Old 01-19-2019, 08:12 PM   #9
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Default Re: Head light focus with out lens?

Jim, I'll try to post pix. It's near zero degrees and salted roads. Car on jacks now for winter storage prep. I may try with a card board about 8 ft ahead of the car. if I can figure how to fit it in my garage. When I did. this, I got about a basket ball size round spot of light at about 15 ft.
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Old 01-21-2019, 12:48 PM   #10
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Default Re: Head light focus with out lens?

Quote:
Originally Posted by sphanna View Post
I thought if I focused my head lights without the lens to make the smallest and round spot that would be a good way to focus. I did this and with the lens replaced, I think I got a reasonably good patterns as shown in the Ford service bulletins. I am open to advice or critique. Thank you.
I'd say you're good. The focus won't change whether the beam is diffused through the lens or not. Also easier to balance the two beams, I'd think.
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Old 01-21-2019, 05:08 PM   #11
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Default Re: Head light focus with out lens?

I agree Badpuppy: I focused while watching the crispness of the light spot. I went too far in one direction and too far in the other direction then balanced in the mid where I had a very nice crisp and very round spot. When I put the lens back on, I had a light pattern like shown in the service bulletins. I am curious why that was not the recommended way too focus. Seems so much easier to me. I do have the new Brattons reflectors which are corrected to original.
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