Headlight stone guards

[Andrew Henshall]

I have been searching globally with no luck for stone guards to suit Lucas PF770 headlights for my Jupiter. My headlights are the normal tripods with flat lenses, so I need a flat guard not a convex one, but it is the 7.7 inch diameter that is the issue. I have looked at many, including both stainless steel and chrome plated brass, but the only ones I can find to suit PF770s are 380 pounds sterling plus freight! These are perfect reproductions of the Jaguar factory rally XK120 ones as fitted to the famous NUB120. I am looking for something much more affordable and more elegant as I think these make NUB120 look quite myopic!

I found one UK supply (Vintage Motor Spares) who's website lists 8 inch diameter flat guards (P/N 704), but as they are unable to supply for some reason they won't even provide a price. These use horrible knurled thumbscrews to attach the guard somehow, which is not what I had in mind anyway.

If I can't buy a pair somewhere, I will make my own using 10mm aperture 16g woven brass wire mesh on a 3.2 mm brass wire ring with brass mounting tabs that attach under the original inner retaining ring screws and have the silver soldered assembly chrome plated. This sounds like something that might be in demand by owners of Jupiters, 1950s Bentley, Rolls Royce, Bristol, and XK120 owners.

Any suggestions?

Andrew Henshall
E1SA433R

[Leo Bolter]

Hi Andrew.

I can understand your concern in wanting to protect your headlamp glasses . . . being flat and not convex makes them even more susceptible to breakage from a flying stone. But at least the replacement of a smashed/cracked flat glass is not too difficult.

But, I would like to point out a disadvantage of some “protectors”. I have had some experience driving at night behind convex plastic headlamp covers . . . normally not a great problem, but at night when it’s raining heavily or sleeting, the scattering of the light caused by the plastic brightly illuminates the droplets just above the front of the bonnet line, then they suddenly disappear making for disconcerting tiny “flashes”. . . . it's almost hypnotic! The removal of the offending shields made a huge difference when driving under those conditions! I suspect that the fitting of chrome/polished wire mesh to the main headlights would probably give the same effect (if not worse!).

But (again), you will most likely not use your car in those conditions if you can help it . . .

Anyway . . . a suggestion, (untried). How about 195*mm discs of clear Acrylic Plastic each with three stainless steel tags made of thin material (0.5mm?) attached to the plastic? The tags would slip horizontally under the outer rim of your lamps. There would need to be a tight “fold-back” in the end that goes under the rim and maybe some firm sponge rubber glued on. Of course the rim would need to be taken off to fit the shields. The rim would be put over the tags and then the rim refitted at the same time as the disk is pressed up against the light unit’s chrome edge. There’d be just one screw on the lower part of the rim to contend with when taking the shields off for cleaning, or for shows.

What are your (and the forum member’s) thoughts on this . .

Cheers.
Leo.
* EDITED (Feb 12): The dimension has been corrected from 95 to 195mm!

[Andrew Henshall]

Hi Leo,

One of the reasons I want to protect the lenses from breakage, even though they are plain flat glass, is because the headlight lenses have already been removed once (to have the reflectors replated in rhodium), and attempting to do so again might result in the rolled brass edge of the reflector snapping off.

It is many years since I ran a car with domed plastic headlight protectors, but I don't remember experiencing the issue you raised with them.

I had thought of flat plastic protectors, but acrylic might not be suitable as I think it yellows with age. I think they would need to be made from polycarbonate. This is not an issue as suitable material is readily available. Your suggestion is a good one as the protectors would be nearly invisible. I had even thought of simply applying a disc of flexible plastic adhesive film to the lenses, as is used commonly to protect car paint these days. It would be very cheap and so could be replaced regularly at minimal cost.

The fact is that the wire mesh I proposed has only a 70% open area, and so 30% of the light output is dispersed or reflected back into the headlight; I feel that a piece of flat polycarbonate would have a higher transmisibility figure than 70%. Given that the headlights are dim anyway (still running a generator), this is also an important criteria.

You mentioned cleaning the lenses, and that is difficult with the wire mesh stone guards I have designed which mount under the three screws that retain the inner retainer. Your proposal, which only requires the bottom rim retainer screw to be removed is much easier.

Thanks,

Andrew Henshall
E1SA433R

[Leo Bolter]

Ahhh . . . polycarbonate ! That's the material I was thinking of but I couldn't remember its name Yes I agree. That's a far better material . . . . stays clear and is tougher too.

I too had to roll back the retaining edge of the reflector. I seem to recollect that they weren't going to be able to stand rolling back again and there was also the fear of the glass breaking in the process, so I trimmed the dodgy edge off prior to plating and eventually glued the glass in with some flexible adhesive (maybe clear silicon rubber?). A added advantage would be that they would have been well sealed against driven rain/hose water.

As a aside, I do remember very clearly being stunned to see, when I went to collect the reflectors from the plating company (after they had been silver plated), the office girl carrying them with her fingers through the bulb hole! There were a couple of lovely finger prints on them before I'd even collected them! They were re-plated!

I'm too am not running a alternator, but with Halogen bulbs I am able to use higher Watts in the main lamps (100/55 W). The ones I could buy here used the same notched, flanged base as the originals, but there was quite a bit of time spent making spacer rings to go under them so as to get a acceptable focus. As supplied they were SO variable as regards focus.* I managed to talk the supplier into letting me take the whole carton home to check all the contents out . . . most of the lamps I tried had a huge black hole in the middle of the beam. Even after selecting the best of a bad bunch, there was need for different thickness spacing rings!

Also, the dimension I gave in my previous post was incorrect of course! It should read 195mm (but you all would have spotted that )

* They were a "name brand" too, which amazed me . . . Philips, Osram or similar.

[Keith Andrews]

There where some of the chrome wire covers and the old chrome eye lash cover thingings (dont know what to call them) for sale on the NZ trademe web site resently

Hang on will see what I can find...(dont know if trademe site will allow hot linking pics...give it a go anyway
http://www.trademe.co.nz/motors/car-par ... 188326.htm


He has a heap of old stuff
http://www.trademe.co.nz/Members/Listin ... er=1580911

And the eye lash thingy....headlight visor
http://www.trademe.co.nz/motors/car-par ... 879297.htm

[Forumadmin]

I am sceptical that stone guards with much more than a 5mm mesh would protect the lamp as a 5mm stone with a closing speed of 100mph would probably break or chip the glass anyway. I have driven the Jup down miles and miles of gravel tracks plus 100000 km of other roads and not suffered a cracked lens although lots of paint chips and windscreen chips. Many of the rally cars have removable guards that only come off when you want to use the lights; but that is usually for the low slung fog lamps.
You could try some (thin) polycarbonate just stuck onto the glass.

[Chris Spencer]

I would not bother with the stone guards but the application of a glass strengthening film should resolve your concerns - it leaves the car looking original - and is an inexpensive solution - these films are self adhesive and readily available via a on line search.

[Andrew Henshall]

[quote="Keith Andrews"]There where some of the chrome wire covers and the old chrome eye lash cover thingings (dont know what to call them) for sale on the NZ trademe web site resently

Hi Keith,

The fundamental issue is that the chromed headlight stone guards advertised on the trademe website are to suit 7 inch headlamps, and the Jupiter uses Lucas PF770s, which are 7.7 inch diameter (as stated in my original post). Hence, they are of no use to us Jupiter owners.

[Keith Andrews]

I dont know if these guys on trademe have others in stock, or other sellers have the required sizes, only asking and doing searches would establish that...at this period in time.
And asking they maybe able to source the required sizes.
Many of these guys also have retail shops /outlets..they are not just 1 offs

[Andrew Henshall]

[quote="Leo Bolter"]Ahhh . . . polycarbonate ! That's the material I was thinking of but I couldn't remember its name Yes I agree. That's a far better material . . . . stays clear and is tougher too.

Bought a piece of 3 mm polycarbonate locally for just A$3 = GBP2, and already have thin strips of stainless, stainless thin washers, and stainless pop rivets in tins in the garage, so everything I need to make two headlight guards to suit our Jupiter's Lucas PF770 headlights is to hand. I calculate that I am about GPB398 ahead compared to purchasing reproductions of the original Jaguar rally XK120 originals (NUB120), so I should be able to spend quite a few hours on the job and still save a fair bit!

Cheers,

Andrew Henshall
E1SA433R

[Andrew Henshall]

Thought I would share the result of my efforts to make headlight stone guards to suit Lucas PF770 headlights with flat lenses as used on Jupiters (plus Jaguar XK120, Rolls Royce, Bentley, Bristol, and Aston Martin models from the early 50s). Thanks to Leo Bolter for convincing me to revert to my original plan to use polycarbonate sheet rather than plated brass wire mesh - they are far less noticeable than wire mesh protectors.

Cleaning the back of the guard and the glass lens is quite easy: just remove the bottom screw and remove the outer rim, which releases the stone guard as it is simply clipped (securely) behind the outer rim. They are easily removed for shows and quickly refitted for the drive back home on our appalling country roads full of potholes and broken bitumen. The brackets and rivets are all polished stainless steel. They are strong enough to withstand impact from a large stone, and because there is 3 mm a gap between the lens and the back of the protector, the lens can not even be cracked by vandals trying to kick out my headlights! Total cost was: materials only A$5.00, plus many hours of my time of course.

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All comments are very welcome.

Andrew Henshall
E1SA433R

[Keith Andrews]

Now turn the head light on for an hr or so , see what happens to the polycarbonate if too close to the heat.
It melts over 300 degs but will start to distort, can start to be 'formed' around 150
Constant heat to the surface forms bubbles..strange as it seems water bubbles.
I have been forming up Poly and acrylic as surounds for my extactor hood above my BBQ on the enclosed decking off the lounge.

[Andrew Henshall]

There were several good reasons why I chose to make my headlight protectors from Bayer Makrolon GP. Given that all headlight lenses are now made from polycarbonate, and all modern accessory headlight protectors are made from polycarbonate, I don't expect to have any issues with my polycarbonate headlight protectors. Besides there is a 3 mm gap between the glass and the polycarbonate, so with the air flow through this gap they are very unlikely to reach anywhere near 150 deg C. If I had made them from acrylic, then I would agree with you that they could distort & possibly melt.

[Keith Andrews]

Besides there is a 3 mm gap between the glass and the polycarbonate

Yes head light protectors on cars I have seen , had and wifes toyota, subaru before that have air gaps, bit bigger than 3 mm thu..

[Andrew Henshall]

Keith,

Why do you believe that my headlight protectors made from Bayer Makrolon GP polycarbonate will melt given that all modern headlight lenses are currently made from polycarbonate and obviously do not have any issues? Modern headlight assemblies concume higher wattage than the Jupiter (and so have a higher heat output), yet their polycarbonate lenses do not melt, which means that my polycarbonate protectors sitting out in front of the lenses should be OK in my opinion.