Citrojim's AX, Pixo, C3, Running and Cycling Tales

[MattBLancs]

Fair enough on both fronts - if sounds tight it'd bother me too!

[CitroJim]

Currently down with Alasdair enjoying a bit of spanner therapy

Whilst Alasdair fought the Xantia steering rack, I happily did a bit of work on Daffodil the AX

Her engine was making two distinct noises: a very typical TU tappet sound and a rather different sort of metallic ticking sound...

I can recognise a TU tappet from miles away but the other one was a bit more mysterious. It seemed to be coming from the vicinity of No. 4 cylinder and I had my concerns.

Firstly, I checked the valve clearances and found all were fine except No. 4 exhaust. It was a bit wide of the mark.

After adjusting and resembling, the tappets were beautifully silent but the ticking remained.

Then I popped off the alternator belt and the noise disappeared... Ahh! Alternator bearings or slip rings... But no, bearings felt fine and spinning it by hand revealed no worrisome feelings...

Then I looked at the belt..

It looked a bit care-worn and had a big tuft of rayon escaping from one side...

This was trimmed off with a small flame and the belt refitted...

Noise gone How odd that a worn belt with a bit of stray cordage could make such a noise... A real 'first'.

Daffodil's engine was back sounding like a fine Swiss watch

I was relieved it was just the belt. The noise sounded like it could have been a little end or broken ring...

A new belt is on order... The old one has definitely see the best of its days...

The quickest and easiest way to obtain one was to visit a local agricultural engineers. We ordered three as both mine could do with a new one.

Alasdair should have them tomorrow...

A good day

[CitroJim]

My day started at 0230 today when I woke up and got ready to depart for home from Alasdair's... I had a great trip back, all roads absolutely clear with just a bit of mist across Salisbury Plain to hinder progress just a little... Non-stop, I did the trip in almost bang-on three hours - at least half an hour faster than usual.

Then once sorted out at home I spent the morning chasing Autumn around a gym set up for children of all ages... I hugely enjoy the bouncy castles, trampolines and just about everything else the play-gym has to offer

In the back of my car was another item rescued along with Alasdair's Rat Xantia. This big battery charger:

Alasdair tried it but it did not work...

I had a look at it today. It's very beefy , albeit a bit crude. Just a transformer, a bridge rectifier, a cut-out and ammeter.

Despite being a bit rusty and cosmetically scruffy, it does basically work. The transformer is good but under load the output voltage sags badly...

It lights an H4 headlamp bulb but the output voltage drops to about 8V in doing so and current is limited to about 1.5A.

The rectifier elements appear to have gone high resistance and this would be likely be as a result of 10 years of being in a damp atmosphere and old age. These rectifiers do deteriorate over time even when well looked after.

And this charger is old. Keen eyes will see it was made in West Germany!

As the transformer is good, the charger is well worth attempting a repair... I'm going to have to source a new bridge...

And here's a bit of devil in the detail. A modern silicon bridge rectifier will have a forward voltage drop of around 0.6v across each diode whereas the metal oxide rectifier as used in this charger has a forward voltage drop of around 0.1v across each diode. If I use a silicon bridge then the resulting output voltage will too low. By about a volt...

I've not looked yet but hope a suitable bridge can be found... Watch this space

[xantia_v6]

I have some doubts on the specification of that charger.

The rectifier looks much too small for the stated current rating, and a metal rectifier would have required more plates due to the low reverse breakdown voltage (per plate).

The general appearance (and fonts) of the charger looks like something from the late 60s or early 70s, which would likely have originally had a silicon rectifier.

[CitroJim]

Oh yes Mike, it's very optimistically rated! 100A boost - no way at all. Not even into a short-circuit...

It's definitely not a silicon rectifier...

[xantia_v6]

I was thinking that the rectifier may not be the original...

Without adding complicated control electronics, probably the best you can do is use power schottky diodes similar to https://befr.rs-online.com/web/p/schott ... sS7pOn6dIR .versions are available with slightly lower Vf, but nothing below 0.4V.

Is the original rectifier full-wave or bridge? I can't quite follow the wiring in the photo.

[Michel]

Loving the spoiler Matt

The AX is full of interesting little details - like the earth points on the strut top washer:

They are for radio interference suppression... Back in the days when almost all in-car radio listening was on AM (MW and LW) it was a constant battle to suppress interference generated from many sources, including the alternator (whine), ignition and dynamo voltage regulator (buzzing) and static discharges generated whilst the car was in motion (crackles) - that's what the strut top earthing is intended to suppress.

Even the wiper motor and cabin blower motor could generate annoying interference.

Both Strawberry and Bluebell have interference suppressors on their distributors.

The kids of today just don't appreciate the epic battles we fought for good automotive radio reception back in the day!

I still listen to AM a lot in the car for Radio 5 Live, both in Bluebell and Polly. Bluebell has a superb original fitment Blaupunkt and Polly's RT45 is remarkably good on AM; unusual on a modern car where AM is very much an afterthought on the ICE system.

I used to fit those Blaupunkts as part of the PDIs I did when I worked at a Citroen dealer in the late 80s.
Suppression used to be a never-ending battle with some of the cars I owned back then. Terrible. None were as bad as my grandad's Reliant Robin though.

[MattBLancs]

My day started at 0230 today when I woke up and got ready to depart for home from Alasdair's...

By 'eck! That is early!

And this charger is old. Keen eyes will see it was made in West Germany!

Probably the weekend before change of a picture, but do you want to see an earlier one? There's one in my garage I've , err, adopted following a garage clearance and I'm sure it's well old!

[CitroJim]

I was thinking that the rectifier may not be the original...

Looks very original to me Mike... And indeed, it is a full bridge... The transformer has a primary tap for normal and boost charge settings and a secondary tap to swap between 6V and 12V batteries.

The use of power schottky diodes is a good call Just to make it functional, a bit of a higher Vf can be tolerated, just means the boost charge setting will be more like the normal setting; at least the charger will be revived and can continue to be useful. I think it's worth it.

Suppression used to be a never-ending battle with some of the cars I owned back then. Terrible. None were as bad as my grandad's Reliant Robin though.

Do you remember the craze for dangling conductive rubber earthing straps from under the car to contact the road and thus discharge static without the crackles? Some also claimed they could cure travel sickness too... How true that is I cannot say as I never put it to the test...

I well recall 30 and 40 or so years ago getting massive static belts from car door handles... Never seems to happen nowadays.

do you want to see an earlier one? There's one in my garage I've , err, adopted following a garage clearance and I'm sure it's well old!

Yes please Matt! Always interested in such things

I remember dad having a very old battery charger using a Tungar Rectifier - another device with a low Vf (forward voltage drop). An example here:

Dad's was still going strong well into the 70s...

https://mullardantiques.co.uk/products/ ... ouston-bth

One reason rectifiers having a low Vf were generally favoured in cheap domestic battery chargers was because they reduced the amount of expensive copper needed to wind the transformer. Also, such rectifiers are quite cheap and they can pass high currents without a generating a lot of heat. The manufacturer saves in all ways, even saving a bit of aluminium to make a decent heatsink for the rectifier...

[RichardW]

Here's mine, charging the battery on my Sister's old Picasso. I've had it nearly 25 years, inherited from my Grandad, must be 60's or perhaps even earlier...

[xantia_v6]

I have a battery charger which is more than 100 years old. It is in NZ, so I can't take a photo right now, but it has a mains-synchronous vibrating reed rectifier.

It looks something like this American Valley Electric charger (but not the same model):



There are a couple of design tricks necessary with a mains synchronous reed rectifier, if the reed is excited directly by the 50 Hz AC, it will vibrate at 100 Hz which is useless for rectification, so IIRC the AC electormagnet acts against a permanent magnet to excite the reed at 50 Hz. The other issue is that the switching contact needs to vibrate 90° out of phase with the applied voltage, which requires a carefully tuned resonant system.

My dad got part way through restoring it about 50 years ago, and I believe that the transformer was OK, it just requires reassembly and tuning.

I will fish it out in a couple of months and take a closer look.

[CitroJim]

Loving the patina on your charger Richard

That vibrator one is absolutely amazing Mike! Does yours have the ammeter too?

In an old book I have, there's details of home-built chargers for 2v radio filament accumulators using a series of light bulbs to drop the voltage and a rectifier in a jam jar full of (I think) salty water and dis-similar metal electrodes... I'll have to dig out details...

If you had DC mains then a rectifier wasn't needed although it was critical to know which was negative and positive... That same jam jar rectifier could be used to find out... One electrode with be surrounded by bubbles and one wouldn't. Can't recall now which generated the bubbles...

[RichardW]

If you had DC mains then a rectifier wasn't needed although it was critical to know which was negative and positive... That same jam jar rectifier could be used to find out... One electrode with be surrounded by bubbles and one wouldn't. Can't recall now which generated the bubbles...

Cathode / negative terminal. All the rage again as there are plans to use electrolysis to generate hydrogen with 'spare' renewable electricity. We are working on a couple of projects for this at the moment - in the Mega Watt scale.

[xantia_v6]

To be honest I have not looked at my vibrating reed charger for 25 years but it has been stored in a safe dry place. I think that it has a meter, necessary to tune the reed.
I think that my dad made a new reed for it and had it working, but the front panel had fairly deep rust pitting and he started making a replica panel. I intend to take a different route and fill the pitting in the original panel while preserving the stamped (or engraved?) legends for the terminals and control.

[Stickyfinger]

The use of power schottky diodes is a good call Just to make it functional, a bit of a higher Vf can be tolerated, just means the boost charge setting will be more like the normal setting; at least the charger will be revived and can continue to be useful. I think it's worth it.

?? Would that not negate the "need" to recover the abused "field" batteries ?