Technical Installing a 123 distributor

Fayray · Aug 6, 2019

I have just received my new 123 distributor and before I remove the old one I wanted to clarify a few things first.

1. There is a spacer and a small clamp in the box. My engine is a standard 499cc unit so I assume I'll be using the spacer? Will it become apparent how the clamp is used when I'm fitting it? The instructions don't even mention it.

2. The instructions say to connect the red wire to the +12v key-contact. So would the positive side of the coil be correct?

3. The factory set curve is 0. 1 has "idle control". Any suggestions on which I should use, or the differences?

It did come with instructions but they are brief and, for my simple mind, seem a bit vague. Everything I've read here suggests it's a very easy job but I just want to be more clear before starting.

Thanks

Hutbed · Aug 6, 2019

These pics should answer the questions. Mine is a '72 with the original 499cc.
Spacer is in, bracket piece in the only way I could make sense of it, and it's been running great for a couple months now. For the setting, I followed the advice I found here and didn't change it from the factory preset. Made a big improvement to idling, response, and overall smoothness. The part that caused me trouble was timing, and I believe I had to swap plug wires to make it work for some reason. Best of luck, you'll love it.

Fayray · Aug 6, 2019

Hutbed said:
These pics should answer the questions. Mine is a '72 with the original 499cc.
Spacer is in, bracket piece in the only way I could make sense of it, and it's been running great for a couple months now. For the setting, I followed the advice I found here and didn't change it from the factory preset. Made a big improvement to idling, response, and overall smoothness. The part that caused me trouble was timing, and I believe I had to swap plug wires to make it work for some reason. Best of luck, you'll love it.

That's just what I needed to see. Thanks very much.

It's also good to see an engine bay with as much "patina" as mine

fiat500 · Aug 6, 2019

Hutbed said:
The part that caused me trouble was timing, and I believe I had to swap plug wires to make it work for some reason.

From experience I think that the 594cc engines and above had the markings for cylinders 1 & 2 the opposite way round from earlier engines. To be certain of timing you just need to make sure that you insert the new distributor in such a way that the rotor-arm approximately faces the block when the engine is aligned with TDC on the timing marks on the pulley and case. Identify which cylinder is on the firing stroke by removing the rocker-cover and seeing which one has both valves closed (ie. clearance at the tappets) and then connect the HT lead from that cylinder to the electrode socket on the distributor-cap to which the rotor-arm is pointing. It then doesn't matter what the markings on the cap says although a bit of re-organising may be needed if you have the proper HT leads which may be of slightly different lengths from each other.

fiat500 · Aug 6, 2019

fiat500 said:
From experience I think that the 594cc engines and above had the markings for cylinders 1 & 2 the opposite way round from earlier engines. .

Mis-information there. :bang: Having looked closely; the caps are marked the same. But when a standard 500 distributor was fitted to my 499 engine, cylinder 1 marked on the cap was the furthest away from the block. Whereas on the 652 engine, when fitted with the 123 distributor, marking 1 on the cap is the closest to the block; I think I have simply fitted the original distributor 180 degrees out, but this proves that it can work in two positions as long as the HT leads are correctly aimed.

Fayray · Aug 6, 2019

fiat500 said:
Mis-information there. :bang: Having looked closely; the caps are marked the same. But when a standard 500 distributor was fitted to my 499 engine, cylinder 1 marked on the cap was the furthest away from the block. Whereas on the 652 engine, when fitted with the 123 distributor, marking 1 on the cap is the closest to the block; I think I have simply fitted the original distributor 180 degrees out, but this proves that it can work in two positions as long as the HT leads are correctly aimed.

that's good to know. The simplicity of just 2 cylinders.

I'll get it fitted this week. Looking forward to seeing how it performs. I have an accuspark system fitted at the moment and it has performed well but the distributor has a fair bit of slop that is causing uneven wear to the contacts inside the cap, hence pulling out the big wallet and stumping up for the 123.

Thanks for your help, again.

Fayray · Aug 7, 2019

Ok, 123 fitted and it would've taken longer if it wasn't for Hutbed's photos, so thanks again. I notice in your photo that the spacer is not fitted?
I too have the situation where I have to swap around the plug leads to get it to work. It runs very nicely too. The original distributor had the 1 lead closest to the engine and the rotor pointing to the engine when at TDC. So I fitted the 123 so it was the same (and as stated in the instructions).
Anyway, it seems to run nicely but I'm yet to tackle the dynamic timing so that'll be next.

Hutbed · Aug 7, 2019

I'm very happy to be able to help, especially after all the help I've received from the other members here. I had assumed the ring below the bracket was the spacer, as my spacer isn't in the box... probably just lost it. Glad you're up and running! Honestly I still haven't done my timing properly. Got it doing so well just "going by feel" that I don't wanna mess with it. Haha

the hobbler · Aug 7, 2019

With modern petrol with its ever increasing amount of Ethanol, the original factory timing isn't always the best---sometimes, as 'Hutbed' mentioned, you can often get a better running engine by setting it up 'by ear'. Set it initially to the factory setting,and then fine tweak it by ear and engine smoothness. Over here in the UK we are lucky in that we still have acouple of sources of 'low ethanol/high octane' fuel----Shell and (surprisingly) Tesco 'Momentum'--both of which are 99 octane. As I have a 'Tesco' petrol garage within 2 miles of my house,I try to always use Momentum in my (tuned) 650 126 engine---it goes very well on it.

Fayray · Aug 7, 2019

Thanks gents. It certainly sounds right and seems to perform well but I'll take it for a decent run before fiddling further. I'm particularly pleased with the cold starting. It's winter here, albeit not a particularly cold one so far, but it has so far started and idled without choke. It definitely didn't do that before, which is good because my choke, or choke cable, is stubbornly not properly returning to the off position (a reminder, I guess, that's there's always more tinkering to be done)

fiat500 · Aug 7, 2019

the hobbler said:
you can often get a better running engine by setting it up 'by ear'. Set it initially to the factory setting,and then fine tweak it by ear and engine smoothness. .

The problem with attempting this on the 123 distributor is that it measures engine speed and applies spark advance according to the input of electronic sensors rather than the mechanical effects of resistive springs as used on a conventional distributor.

So it has a variety of pre-selectable levels of ignition advance, which all have their own curve pattern and will suit different levels of tuning and may be appropriate to different types off fuel. These are what you are meant to use in order to match the amount of advance to your specific situation. If you tweak it by ear I think you may upset the range in which the carefully designed curve operates. It may be better to try a different curve instead; or do what I did and set it a the "0" curve (from the table on the link) and the dynamic timing by a simple strobe and precisely "by the book". This has resulted in thousands of miles of smooth and reliable engine operation.

http://www.123ignition.nl/product.phtml?id=27

Hutbed · Aug 8, 2019

fiat500 said:
If you tweak it by ear I think you may upset the range in which the carefully designed curve operates. It may be better to try a different curve instead; or do what I did and set it a the "0" curve (from the table on the link) and the dynamic timing by a simple strobe and precisely "by the book". This has resulted in thousands of miles of smooth and reliable engine operation.
http://www.123ignition.nl/product.phtml?id=27

When installed, is there an easy way to do this? Seems like I'd have to remove the entire assembly to get a little tool in there to adjust, definitely in order to see what I was adjusting it to.

fiat500 · Aug 8, 2019

I think you're correct. Partly why I don't mess with it.[emoji6]

Fayray · Aug 8, 2019

fiat500 said:
The problem with attempting this on the 123 distributor is that it measures engine speed and applies spark advance according to the input of electronic sensors rather than the mechanical effects of resistive springs as used on a conventional distributor.

So it has a variety of pre-selectable levels of ignition advance, which all have their own curve pattern and will suit different levels of tuning and may be appropriate to different types off fuel. These are what you are meant to use in order to match the amount of advance to your specific situation. If you tweak it by ear I think you may upset the range in which the carefully designed curve operates. It may be better to try a different curve instead; or do what I did and set it a the "0" curve (from the table on the link) and the dynamic timing by a simple strobe and precisely "by the book". This has resulted in thousands of miles of smooth and reliable engine operation.

http://www.123ignition.nl/product.phtml?id=27

Peter, to do it precisely, how do you know when you are at 3000rpm?

lazylobster · Aug 9, 2019

Are the later 123 units not bluetooth enabled? I thought this was the case and remote tuning could be done via your phone / app.
R

fiat500 · Aug 9, 2019

Fayray said:
Peter, to do it precisely, how do you know when you are at 3000rpm?

In my case I don't have a strobe which reads RPM. But as maximum timing does not advance past whatever setting you have applied to the 123, any fast running of the engine should do for using a strobe.
On mechanical distributors, the springs might wear or be damaged and your couldn't be certain that any setup was exactly to spec, so after static checks, dynamic testing at speed was the way to verify that you had full advance, even if this was to then upset static timing. On the 123 the full advance will always be correct as long as the initial setting is correct. So in theory you could simply check with a strobe that you do have 10 degrees advance at tickover.

fiat500 · Aug 9, 2019

I don't think they are.

lazylobster said:
Are the later 123 units not bluetooth enabled? I thought this was the case and remote tuning could be done via your phone / app.
R

Fayray · Aug 9, 2019

lazylobster said:
Are the later 123 units not bluetooth enabled? I thought this was the case and remote tuning could be done via your phone / app.
R

I believe some models have this feature but from what i could tell it's not a feature available on the 500/126 unit

Hutbed · Aug 9, 2019

I saw the option of bluetooth available, but it made an expensive dizzy even more so, and honestly I didn't want more sensitive electronics in the engine bay. I've got a makeshift tinfoil heat shield between the engine and my dizzy as it is until I can figure out a better solution (there are several reported cases on the forum elsewhere of the internal electronics being cooked from excess heat).

Fayray · Aug 9, 2019

Hutbed said:
I saw the option of bluetooth available, but it made an expensive dizzy even more so, and honestly I didn't want more sensitive electronics in the engine bay. I've got a makeshift tinfoil heat shield between the engine and my dizzy as it is until I can figure out a better solution (there are several reported cases on the forum elsewhere of the internal electronics being cooked from excess heat).

oh really? I couldn't find it. The one feature I'd heard about that I particularly liked was the ability to disable the electronics via the app so it couldn't be started by a thief. Currently the anti-theft consists of door locks and ignition switch which can be hacked using around 1 in 3 other car/padlock keys and the location of the starter lever which most thieves are unlikely to be aware of

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