I have been chasing the source of a knocking sound from the engine. After blaming the poor alternator (which does have worn bearings), I traced it to the distributor. I had already suffered damage to a rotor-arm which collided with the inside of the cap, and the replacements seem to be heading the same way....the source of the knock?

I've removed the 123 unit and replaced with the correct, unmodified, points distributor. The engine instantly fired into life and is likely to stay with this setup from now on.....knock now gone.

The alloy plate at the top of the 123 can be pulled up and down...maybe normal. But when I push up pull down the distributor pinion and turn the shaft it feels extremely rough.

I get the impression that the manufacturer isn't interested in after service, so as this is a mechanical issue I may get round to dismantling it myself.

Not good for 30,000 miles.

I would be interested to see pictures of the internals and how they may differ from a standard distributor. I have a couple of the older type 123 electronic ignition set ups which sit on an original distributor body.

Toshi 975 said:

I would be interested to see pictures of the internals and how they may differ from a standard distributor.

Click to expand...

So far, I've removed the pinion and find the shaft is very simple to remove, with a washer below the body, bearing on a brass insert, and the alloy spinner-plate at the top, with a few shim-washers beneath;these are to take up any vertical play. I think it's additional shims I need, as the heads of three philips screws in the body, which presumable allow removal of the electronic module, have definitely been catching on the underside of the spinner.

Photos to follow.

When I rebuilt the 6 distributors last year the thing I was short of was the Tufnol thrust washers that fit between the spindle and body. All but one had worn away and you can’t buy the part. So I ended up buying a sheet and making my own. Still got some left if you should need a bit

On stripping it down I found another problem that I hadn't been aware of. The two cables which externally, look very secure, had presumably been vibrating and bending to the point where both of them had exposed wires. This was a breakdown waiting to happen; looking back over the last few months, I think they may have been partly resposible for a few jitters I've experienced.

It's as I suspected, it looks like the thrust from the action of the camshaft gear on the distributor has caused an upwards and downwards movement on the spinning plate which exposes the LED. If I can shim that out using washers from a standard distributor, maybe it will become useable again. The problem is that the two existing shims in the third image are of a greater diameter than the brass tube in which the shaft rotates. This means that they are bearing on the green insulator rather than the top of the tube itself, which can't be a good mechanical solution.

However, this all puts paid to the "fit and forget" of the advertising blurb about these things. It's possible that few people have tested them in real-world conditions for any length of time and that this is a design issue. There's certainly no way the unit has been abused and it's hard to see how the mechanical side of things could be misused.

I'm possibly going to write to the company, with little hope of any sympathy, and to ask them what they think about this.

So my love/hate relationship with these things now terminates at HATE...not recommended.

Peter, I would deffo go back to the company and give them the feedback. It can only be good for their product long term to have this real world usage.

R

That’s pretty poor considering how much they cost and clearly they haven’t done enough testing in the real world to justify all their claims. I would imagine, unfortunately, in the real world the vast majority of people probably don’t do anywhere near the mileage that you do but that doesn’t allow them to escape responsibility for selling something that is to be honest is poorly engineered.

Looking at it again in retrospect, the wiring should have had an outer sheath on it where it goes into the gland to prevent the wiring insulation from getting damaged. Even if it was just a short length of 3-4 cm, as what has happened is as the gland has been tightened it has damaged the insulation which isn’t designed to be crushed like that. Mine is sitting on a shelf as I don’t use it being distributorless but I will modify it with some heat sleeving to prevent that happening if I need it again.

I assume the little circuit board sits below the green insulation plate? What triggers it to provide the spark and discharge the coil? Obviously done on rotation but there must be sort of sensor that picks up something on the shaft as it rotates?

To be fair there really isn’t a lot to it is there, not for the money they sell them for. I suspect you will have zero luck with them though, as in admitting liability they would be confirming it being down to poor design and lack of real world testing.

lazylobster said:

Peter, I would deffo go back to the company and give them the feedback. It can only be good for their product long term to have this real world usage.

R

Click to expand...

I've written to them and sent some images. The attitude I have taken is just to describe the whole situation and to suggest that my experience may be useful to them in designing for longevity; I'm not requesting repair or replacement. From the lack of interest they have shown in my my previous queries about advance settings and reports from the Internet by other disgruntled consumers, I don't really expect a response.

Vitesse said:

there must be sort of sensor that picks up something on the shaft as it rotates?

Click to expand...

I assumed that the two open slots in the rotor were involved in spark timing. I think it's an optical device and that the LED is involved in that; as you know electrio-onics is not my field strength.

fiat500 said:

I assumed that the two open slots in the rotor were involved in spark timing. I think it's an optical device and that the LED is involved in that; as you know electrio-onics is not my field strength.

Click to expand...

Yes you are probably right. Those slots would allow you to adjust the timing and there is a little square on the green insulation plate that appears to align with the slots and it probably sits on top of a component on the circuit board that does the switching.

this user had an issue that was repaired by 123. They comment on the video (first comment under the video). Maybe worth including a link to this thread in your correspondence? https://www.youtube.com/watch?v=xs8wDQreHC4
BTW, this guy's videos are excellent and there's a 500 in the queue as seen in the background of this video

Fayray said:

this user had an issue that was repaired by 123.

Click to expand...

Thanks Andrew; that one had come up in my searches. That guy was really fair and supportive of the 123 and blames himself for what went wrong. Although he had done a massive mileage, the issue was electrical and caused by a power surge when the king-lead dropped off the distributor.

I await a response from the company, but if anyone is going to repair the item, it's likely to be me.

I've had a friendly email from the 123 Ignition Shop and my email has been passed on to Albertronic, which appears to be the manufacturing arm of the business.

I have rebuilt the distributor and incorporated a couple of simple modifications.

In order to stop the underneath of the spinner from catching on the heads of the screws I have supplemented the two existing shim-washers with a couple more. These are spares from a conventional distributor and although they have the same internal diameter, the outside is slighly larger. I think this may be good thing if it spreads the thrust over a broader area. It seems poor practise by the manufacturer that the three tiny screws which secure the PCB to the body are countersunk over a plate plate. This means they stand up a bit more and they are less secure than they would if they were pan-heads, which would sit more securely and flatter on the surface. The rotating shaft still has a small amount of movement in the vertical direction, which matches the way that the standard distributor is setup. I put a light smear of molybdemum grease at all points of contact.

I was going to cut the wires and re-solder them to the board. But as there is nothing wrong with the electronics, it seemed to tempt fate to introduce my amateur soldering techniques to the situation. It was only the insulation that was cracked and the copper wires are intact; so I sleeved each one with heatshrink and the put a combined heatshrink tube over both wires before sliding them through the gland-nut.

I haven't tested it yet but I'm pretty sure it's now "good-to-go". But if I do use it again there will definitely be a spare distributor in the boot at all times.

I find it interesting that the electronics have been the most robust part of this device. The worries I have previously seen expressed by potential purchasers have been that if the electronics let you down, you will be stuffed in a way that can't be sorted by the roadside. Whilst this is still true, it's madness that it is some very basic mechanics which are the actual weak point. The original Magnetti Marelli and Zelmot distributors are incredibly well made and reliable in comparison.

I for one love reading Peters threads... not only for the stunning views he posts to make us all jealous...
but for the trials and tribulations of running a Fiat 500 in such terrain as Scotland and how he finds all the little niggles and improves the reliability...
Perhaps there is a Book in the wings...

Bigvtwin996 said:

I for one love reading Peters threads... not only for the stunning views he posts to make us all jealous...
but for the trials and tribulations of running a Fiat 500 in such terrain as Scotland and how he finds all the little niggles and improves the reliability...
Perhaps there is a Book in the wings...

Click to expand...

That's very generous of you to say. I hope that the things I report back from the "front" encourage people to have more confidence in the abilities of the Fiat 500. Attention to detail is the key to enjoying this car.

There won't be a book, but detailed vlogging is under consideration. [emoji846]

I think my 123 has given up the ghost as well. After the engine rebuild, little Martina would still occasionally cutout momentarily when hot and under load - she did this with the old motor as well. Since the only things the same between the old motor and the new were the fuel pump, dizzy, and coil (a brand new Bosch blue), that narrowed it down.

I cleaned up a spare dizzy outfitted with a Pertronix (Hall effect) and gave it a go. No spark. Troubleshot the coil and couldn’t get any read across the posts. Nada. Fitted a spare Bosch coil I had and she fired right up. Set the timing and she didn’t skip a beat during a hard test drive.

Looks like the 123 might’ve taken out my coil on it’s way out. The cap contacts look rough and I could hear some minor contact on rotation. Not sure what failed, but it appears it’s toast.

Just something else to look out for here. I think I’ll stick with the pertronix unit from here on out.

“If it ain’t broke...”

As I have mentioned before, it is the heat that kills the electronic ignition systems, all systems. I have put a 'dam' in my thermostat housing to direct hot air away from the distributor. When I measured the temperature on the distributor body and the thermostat housing (with a 'laser' temperature gun) the temperature of the distributor body was a good 10 degrees (C) cooler than the thermostat housing. I am going to carry out more checks on this---and i also carry a 'points' distributor in the car along with a simple test lamp (for static timing)---once bitten, twice shy!

the hobbler said:

I have put a 'dam' in my thermostat housing to direct hot air away from the distributor. When I measured the temperature on the distributor body and the thermostat housing (with a 'laser' temperature gun) the temperature of the distributor body was a good 10 degrees (C) cooler than the thermostat housing. I am going to carry out more checks on this---and i also carry a 'points' distributor in the car along with a simple test lamp (for static timing)---once bitten, twice shy!

Click to expand...

Tom, any pictures of your dam arrangement? That’s a good idea that I think I may steal for my spare motor. Or at least play with fabricating something.

I did an article for the "Fiat 500 Enthusiasts Club" magazine re. the 'dam'. I willsort it out and send you a copy Matt.

Can I have a copy too please Tom?
Cheers
Rob