RHD Bosch H4 lens question

[Dougieboy1]

Hi Ian,

the 2 photos on the early 911 link are of the same reflector. One is a front view and one is a rear view. It is identical to the non city light in the headlight photo I posted - in all the photos (mine and the early 911s link), you can see the tabs sticking through for the bulb reflector

As i said earlier, i am not an H4 expert by any stretch but i dont subscribe to the left and right hand drive reflector theory even though they may have different part numbers (which i cant find in my parts listing for some reason, not even in the numbers reference section N at the back).

The reflector is mounted in the headlight surround and there are 2 longish screws which can be used to alter the up and down orientation of the reflector. The final left and right adjustment I believe is done by the prism of lens, not the reflector. Its why you can alter RHD lenses for LHD driving by covering up the relevant prisms with the plastic masks you can buy from the AA.

The headlights i have are identical to the ones in the photos, just fitted with right hand drive lenses.

Happy to be proved wrong.

AWD

[inaglasshouse]

i am not an H4 expert by any stretch but i dont subscribe to the left and right hand drive reflector theory even though they may have different part numbers

Agree. I've taken apart quite a few H4s, LHD and RHD. Unless the difference is very subtle, I reckon the reflector is identical and the required LHD-RHD beam pattern modification is made by the lens (and perhaps with the adjustors).
By the way, although I've not discussed H4s with him, John Audette tells me the same is true for H1s (only difference is the lens).

[IanM]

Chaps,

Thanks for the explanation.

[IanM]

You can see that the top sector is clear, no 'pebbles'. Unfortunately, it is a LHD lens so not any use for my car.

Dougie,
I think that glass lens is actually H1, not H4.

[IanM]

Another question - Are the LHD and RHD H4 assemblies (apart from lenses) the same? Can you just simply swap the lenses if you want to convert to other side traffic?

Below are 2 borrowed photos from the internet (no affiliation). The first pic is LHD and the second pic is RHD.
If you look the clip hinge at the bulb holder that holds the bulb down, you'll see that RHD clip is opposite handed to the LHD clip. But I don't understand why because the bulb in both versions seems to be orientated in the same way.

Please enlighten me

[Jonny Hart]

The clips can be fitted either way.

[IanM]

OK thanks.

[BILLY BEAN]

[quote="IanM"]Thanks for the pics.

I've just checked the parts catalogue (1965-1969) and apparently the reflectors are not common. Part number as follows:

Reflector LHD
901.631.103.00

Reflector RHD
901.631.103.01

So, they're not the same. Does anyone here know if they can be easily converted?

The different reflectors you quote for 1965 to 1969 may be correct. However, in my distant memory, I don't think H4 bulbs became commonly available until around 1970. So the relectors for which you quote the part numbers are not for H4s. Happy to be corrected by my even more mature DDKers or blokes who actually know what they are talking about!

[IanM]

Just thought I'd update this thread as I recently found out that the difference between RHD and LHD H4 headlights (apart from lenses) is that the bulb-holder is rotated by a few mm (approx 6 or 7 mm).
The impact bumper H4 headlights cannot be converted because the bulb-holder is spot welded to the reflector shell, but not sure about the earlier units like 4487/7045. Anyone know?
Anyway, look out for the part number on the yellow label on the back of IB H4's, 113 = LHD and 112 = RHD.

Another subject - I've been looking at the 356 catalogue and apparently there were no RHD versions at all. The three available versions were as follows:
Asymmetric (LHD)
"Normal" symmetric
USA sealed beam

Does it mean the RHD 356 got the normal symmetric headlights?