HID light kits?

Well then why on earth do people buy the kits ?

I don't give a crap what my dipped beam bulbs are doing - it's the main-beam bulbs that you use to see where you're going !

And I was considering buying a HID kit too.

Pah !

It's already been quoted. Read the previous posts, FFS !

Here it is again :

1. a. a headlamp missing or so damaged or deteriorated that its function is impaired.

My headlight was deteriorated. It's function was impaired.

Which bit don't you understand ?

So ? If they're not damaged or deteriorated, then it doesn't matter one jot whether there is low light output !

I say again : It failed because one of the reflectors was shafted.

It had tarnished, and wasn't shiny any more. There was NOTHING wrong with the beam pattern - it was exactly the same as the other good headlight. It failed because it was DIM.

Which bit don't you understand ?

You must live in a very quiet part of the country. I've almost forgotten what main beam looks like.

Were you born thick or had to work at it?

You can't have a correct beam pattern with the reflector or glass damaged. Even a kid could work that out.

The light intensity has nothing to do with it - although a tester will realise that if the reflector is damaged there's no point in even checking the beam setting.

I think a lot of people have a pair of units in their shed / back of the garage, etc. The reputation for going wrong is not earned and the pop up lights still keep working just fine in their third decade. Course, there are always a few minor fixes, e.g. if a diode blows, the light might not go up. Easy enough to solder a replacement in. The motors, well, I've yet to see a broken motor per se.

AFAIK the sprint was OHC so no if they were, but TBH I have an SD1 engine rather than the four cylinder anyway. Someone probably knows this, though.

If you mean the Triumph v8 engine, these are getting a bit rare on account that many Stags had the SD1 put in instead.

Neither thanks.

How about yourself ?

Of course you can !

In kids terms : Let's say your reflector is 80% reflective. You get 80% of the bulb light out of the headlight. Now, let's reduce the reflector's reflectiveness to 10%. You now get 10% of the bulb light out of the headlight.

Nothing else has changed.

Why do you think the second scenario would change the shape of the beam ?

There would be much "less" of said beam, but it would still be spread in the same directions, by the same not-as-reflective reflector !

"Reflector or glass damaged" is the term used. In the real world you will not get uniform 'damage' which will drop the reflectivity across the whole reflector by a set percentage! Hence the beam pattern will change if the reflector or glass is damaged. IMHO.

Will

If you have a reflector which has simply lost some of its 'reflectiveness' in an even manner, you'll still pass an MOT, as the beam pattern will be fine. But what will fail is where the silvering has failed in one or more places as this will effect the beam pattern, and this is the usual scenario. By the time all the plating has disappeared, you'd have failed several MOTs.

I'd suggest you read up on some basic optics.

That's *exactly* what I got. The reflector just tarnished, and hence lost it's silver coating.

I didn't.

Beam pattern was fine, but I failed because

1. a. a headlamp missing or so damaged or deteriorated that its function is impaired.

Not the case.

What for ? There was nothing wrong with the optics of my statement. If there was, you'd have pointed them out !

So to clarify, you're saying that the reflector and glass were in perfect condition other than the refector having uniformly changed colour?

Care to say what make of headlamp this miracle happened on?

I'm talking about excessive noise, rather than blowing.

If a tester sees a baked been tin tailpipe, and if that makes him think it is louder than standard, then he can see compared to the standard car, it is excessively loud, without having the standard car there to compare with.

Yep, spot on.

The silver reflector had tarnished, and hence turned a sort of browny-gold colour.

It was a Pug 405, so it was probably a Valeo unit if it was the OEM item - I didn't buy the car brand-new though, so it could well have been a pattern part.