Technical More questions about setting 123 ignition.

[fiat500]

Just when I thought I had it sorted (and the engine is running really well now) I have dug up some more confusing information.
The first is that on the post 1985 engine, the manual gives three positions for checking the timing:

1. @ 700 rpm = 10 BTDC
2. @ 3000rpm = 14 BTDC
3. @ 3850rpm = 21 BTDC
I can now use the strobe but have no way to check those rpm's accurately.

The second thing is that the 123 ignition manual:

http://www.123ignition.nl/pdf/FIAT2R.pdf

states that timing should be

1. @2000 rpm = 16 BTDC
2. 3000 rpm = 28 BTDC

This seems very contradictory and confusing.
I have set mine at 18 BTDC on very fast revs. It runs and starts well but has anyone actually set the 123 as described?

The final thing is that there is a setting 1. on the distributor for "idle control". What is that and is it any advantage to me?

 

[Vitesse]

I have a exhaust gas analyser that I bought years ago that I used to use when balancing the SU carbs on my Vitesse, strangely enough!!! The good thing about it is you connect it up to the coil and it gives you a tachometer read out. There must be some kind of remote digital tachometer available that you can connect to the coil?

I could have a tinker tomorrow and see how mine is timed at those rpm suggested. I havent a clue what that setting 1 is? Maybe you set the carb up at idle on this setting???

 

[jjacob]

You should be able to use a standard tach/dwell meter and set it on the 4cyl scale. Then just double the reading on the meter for the correct rpm. I think doubling is correct. Anyway, whatever reading you get either doubling it or dividing by two will get you the right rpm. It will be obvious. This is what I did on my 500.
John

 

[thepuddlejumper]

It was a long time ago when I set up my 123 distributor, but If I remember correctly the No 1 setting is for standard tune with the other curves for different tuning setups. I will see if I have the original instructions and check.

Ralph

 

[fiat500]

It was a long time ago when I set up my 123 distributor, but If I remember correctly the No 1 setting is for standard tune with the other curves for different tuning setups. I will see if I have the original instructions and check.

Ralph

I've put in the link to that Ralph:

 

[F123C]

Peter, now you see what happens when you go and buy a strobe-timing light!

Gunson's used to sell a 'tacho-strobe'. It was a stroboscopic timing lamp with a built in rpm 'indicator' on the side (a type of prism affair).

As jjacob above says it should be possible to use a tacho/dwell meter and allow for having only 2 cyls. Some multimeters designed for automotive use also have a rev counter built in. Afaik e.g. Draper still do one of this type. Maybe Gunson's also?

Another possibility is to get hold of either an accessory type tachometer (revcounter) or one from e.g. an older Fiat. (124 Sport Coupe/850 Coupe).
These usually only require a live supply, an earth and a connection to one side of the ignition coil in order to work.
Problem is these rev counters are not very accurate indicators particularly if used on 2 cylinder engines, so a stand alone test meter is prob. better.

There's also optical? revcounters that measure rpm from e.g. a piece of refractive?/reflective tape attached to a rotating shaft/pulley. Some truck w/shops use them.
There's also contact revcounters which have a ball end that is held against the centre of a rotating shaft. Some lathe owners might have one.
The above two type are used in industry to measure rotational speed of equipment which doesn't have car type ignition pulses that can be measured. They tend to be pricey but sometimes come up at auction when an engineering business sadly closes down or maybe you work or know someone who works in such a field and could borrow such an item of equipment....

P.S. Us old style mechanics could tell rpm by ear. I could, until I went 1/2 deaf from adjusting multi-carbs using a piece of garden hose from the carb intake held up to my ear. 'Vitesse' above prob. knows what I mean!...

Al.

 

[fiat500]

Thanks Al.

I doubt I will be going so deep into matters. When the engine sounds fast, for the sake of argument I will call that 3000 RPM. My problem is that I can't believe that the 123 people could make a mistake with their advice of setting for 28 degrees BTDC but that really sounds like a mistake. The fact that the thing is first installed at TDC and that static timing of 10 and dynamic of 18 add up to 28 might be significant...but although it adds up, it still doesn't compute for me.

I have written an email to them in search of the explanation.

 

[fiat500]

I have written an email to them in search of the explanation.

By the way, I did get a reply on that....the obvious (now) fact that you add static and dynamic timing together to make the total advance.:bang:

 

[Bambino]

The attached graph is taken from the Shop Manual. It's used when checking, testing and calibrating the distributor. Once the static advance is set at 10deg BTDC the dynamic advance starts to kick in around 1400rpm, peaking at 3000rpm (+18deg) in a linear fashion.

I'm not sure what the 123ignition curves look like. I imagine the 10deg is built into the algorithm as these distributors are set up with the pulley at TDC, not 10deg BTDC.

Chris

 

[fiat500]

I suspect that on an aged points distributor, the "curve" is more like an actual curve. It will already be out of spec so manual twiddling may help. If the hype about the 123 is true, it will follow that straight line advance to perfection. That being g the case, if you physically move the distributor to gain some advance because of fuel type or simply because the engine seems to take it, the timing of the spark will be wrong at all engine speeds. I think this is what previously gave me poor performance. So as described on another thread, my next move would have been to try a different curve setting
As it happens I am now delighted with the engine performance and I'm touching nothing.?

 

[Uaglio]

The final thing is that there is a setting 1. on the distributor for "idle control". What is that and is it any advantage to me?

Don't mean to dredge up a old thread, but curious Peter, did you ever get an answer to this? I'm working on getting my timing and carb adjustments set this weekend (provided my oil pan stops leaking!), and I too noticed that the 123 Ignition custom curve setting #1 speaks of "idle control," but otherwise has the same advance timing curve as setting #0 (16.8 BTDC at 2000 RPM and 28 BTDC at 3000+ RPM).


What's "idle control"? Sure sounds like something I'd like stable Maybe it's just another timing tweak to try if you can't get a steady RPM at idle using default setting #0?

 

[fiat500]

I never got the answer and maybe I'm missing a benefit of the 123. The manufacturer is stupid because they're also missing some additional, potential selling points. Instead I think sales are a sort of viral phenomenon with people influenced by good explanations of the basic design principles by the company and then by the subjective feedback of users. But I have no answers unfortunately.

 

[Bigvtwin996]

I never got the answer and maybe I'm missing a benefit of the 123. .........................

I think as I have said before we are all used to modern cars, that we don't lift the bonnet to adjust things...


In ye olden days, checking points and plugs was just something you did.... as was checking the mixture and adjusting the carb....but when did cars stop having points?? and plugs just get changed as a service item.... and Fuel injection has removed the adjustment of carbs.. I can't remember other than a 500, VW or Lotus when I checked and cleaned them...

I think that is why people (myself included) like the 123 setup nothing to adjust fit and forget...

 

[Uaglio]

I never got the answer and maybe I'm missing a benefit of the 123. The manufacturer is stupid because they're also missing some additional, potential selling points. Instead I think sales are a sort of viral phenomenon with people influenced by good explanations of the basic design principles by the company and then by the subjective feedback of users. But I have no answers unfortunately.

I stumbled onto this post on 123’s “forums”. https://www.123ignitionshop.com/gb/forum/336s/how-work-idle-control

It’s not clear, but sounds like idle control has something to do with controlling (preventing?) idle speed increases that seem to be inherent with timing advance. I planned on dialing back idle speed on the carb set screw once I got the timing set.

 

[fiat500]

I stumbled onto this post on 123’s “forums”. https://www.123ignitionshop.com/gb/forum/336s/how-work-idle-control

It’s not clear, but sounds like idle control has something to do with controlling (preventing?) idle speed increases that seem to be inherent with timing advance. I planned on dialing back idle speed on the carb set screw once I got the timing set.

I see the explanation and that's definitely true if you simply rotate a standard distributor. But as the 123 governs the timing of the spark electronically I expected that choosing different degrees of dynamic advance should not affect the static.
Admittedly, the static can be upset slightly from its set point if you use a strobe to verify the dynamic advance so maybe the setting adjusts for that slight "wobble" .
In any case, one of the big selling points of the device is the smooth and even tickover, which on the standard setting I can attest for.