You may know I have already asked this question in a more long-winded way. But can anyone enighten me about this 28 degrees setting.

Since accurately adjusting the timing with a 123 distributor to the 18 degrees, which I thought was correct, the engine is running well but is distinctly sluggish even on gentle hills.

What has everyone else set their distributor to?

The instructions say 28 degrees which I will try tomorrow.
It seems that the manufacturer is not good at aftersales support; this is even stated on their own website. It says that they prefer to use their time on research!?:bang:

Don't know about 123 system but my car runs on a magnet pick up likes better a setting of far more of 18 degrees as the book says. Mine runs better to around 24 degrees and as discussed here with others we conclude that it likes more advance than manufacturer setting. So go for it and see how it will go.

Hi Peter,

The max advance shown in the 126p owners manual is 21 degrees +/- 2 degrees at 4000 rpm. Maybe try that. That's for a 650 but maybe try it anyway.
You might also try re-adjusting the fuel mixture with your new timing. Maybe running a little rich or lean at higher rpm? Maybe pull a plug and check its colour.

John

I'll try 21* then; in fact I'll try to do it by ear and then check what it actually is.:idea:
The mixture is just right at the moment as judged by plug colour, because I had the plugs out the other day to dry the outsides when I had my latest engine washing incident after the rocker-cover leaking incident (will I ever learn?). The car has been thrashed around well over 300 miles over the last four days.
I read that there is a 123 ignition Forum so I might have a look around there for an answer. In fact, rather pathetically I feel, that is exactly what they recommend that you do if the answers aren't on their FAQ.

I'm pretty sure that Chris "Bambino" has one installed on his car. Isn't there a selection of advance curves to select for the 123 distributor setup?
John

jjacob said:

I'm pretty sure that Chris "Bambino" has one installed on his car. Isn't there a selection of advance curves to select for the 123 distributor setup?
John

Click to expand...

Yes, you can select 16 different curves but only two of them are for the basic 500 and 650 engines. There are two for the 600 engine and the rest are for various states of tune.
Other recommended maximum advance settings on the tuned curves are 26 and even 32 degrees.
Lots of people seem to have this device. Everyone seems to have great things to say about it. Most people have noted correctly that it should be set by stroboscope for maximum accuracy.
I have never seen anyone mention that they have set the distributor to 28 degrees, which I find quite baffling.

Maybe this Forum has a wider audience than I thought? Shortly after my last post I unexpectedly had a reply from 123 as follows:

10 degrees static timing + 18 degrees dynamic timing makes 28 degrees.

I still don't understand that as I didn't think these timings were cumulative. But now I have decided to go straight to 28 degrees and hope the engine survives.

I'm still awake thinking about this and the only conclusion I can make is that in the conventional distributor, the additional advance caused by the centrifugal mechanism is 18 degrees. I had assumed that this addition would be 8 degrees, which when added to the 10 degrees of the initial setting made 18.
The 123 is initially, physically set at 0 so in order to match that spec. it needs to show 28 degrees under the strobe.
This is the only explanation I can come up with but seems odd to me.

fiat500 said:

I'm still awake thinking about this and the only conclusion I can make is that in the conventional distributor, the additional advance caused by the centrifugal mechanism is 18 degrees. I had assumed that this addition would be 8 degrees, which when added to the 10 degrees of the initial setting made 18.
The 123 is initially, physically set at 0 so in order to match that spec. it needs to show 28 degrees under the strobe.
This is the only explanation I can come up with but seems odd to me.

Click to expand...

Me thinks you are right.
John

fiat500 said:

I'm still awake thinking about this and the only conclusion I can make is that in the conventional distributor, the additional advance caused by the centrifugal mechanism is 18 degrees. I had assumed that this addition would be 8 degrees, which when added to the 10 degrees of the initial setting made 18.
The 123 is initially, physically set at 0 so in order to match that spec. it needs to show 28 degrees under the strobe.
This is the only explanation I can come up with but seems odd to me.

Click to expand...

I must admit that I thought that the angles were additive - that is, 10deg static plus 18deg dynamic to give a maximum advance of 28deg.

When I set up my 123ignition, I initially set the advance according to the instructions. The engine started but accelerated roughly until I dialled in a bit more advance - I guess compensating for increased compression, different cam profile, unleaded petrol etc. etc. I don't know what the final figure was except to say that its probably a couple of degrees more than 28. So far I haven't destroyed anything with the possible exception of my reputation

If you have an old distributor lying around and you can lay your hands on a protractor, you can get a rough idea of the maximum advance by measuring the degree of rotation of the rotor when the advance weights are shifted.

Chris

Yes, it's all becoming clearer now. I now doubt that most people have actually set their engined up precisely, despite the warm words I have read about timing with a strobe.
I don't think that matters, but if you do use a strobe on this electronic distributor, you need to be aware of the significantly different timing mark you must make on the pulley.

Bambino said:

....................
.............................
....................

If you have an old distributor lying around and you can lay your hands on a protractor, you can get a rough idea of the maximum advance by measuring the degree of rotation of the rotor when the advance weights are shifted.

Chris

Click to expand...

Iirc, you would need to double the angle measured this way to get the max. advance figure as the distributor and camshaft are driven at half crankshaft speed and you're checking ignition timing at the crankshaft pulley. So, e.g. if you measured 10 degrees at the advance unit this would equate to 20 degrees advance (in addition to the static timing figure!) at the crankshaft pulley.

Some distributors (can't remember if this includes Fiat one's) had the max. advance marked on the baseplate? of the auto-advance unit, or possibly indicated on the outer distributor body with a dab of colour paint? Maybe someone could carefully examine a dismantled distributor?

Al.

F123C said:

Iirc, you would need to double the angle measured this way to get the max. advance figure as the distributor and camshaft are driven at half crankshaft speed and you're checking ignition timing at the crankshaft pulley. So, e.g. if you measured 10 degrees at the advance unit this would equate to 20 degrees advance (in addition to the static timing figure!) at the crankshaft pulley.
Al.

Click to expand...

Yep - thanks Al. I was also hoping someone would actually do the experiment

For a 4-stroke engine, TDC to TDC for any cylinder on the compression stroke takes 720deg of crankshaft rotation while the distributor rotor only turns through 360deg. So yes, if you do the protractor thing and get an angle of 9deg then the max advance is 18deg above the 10deg static making a total of 28deg on the pulley.

... or so I believe

Chris

Yes, Chris.

And I was hoping you'd do the experiment!!!! And strip down a distributor and look for elusive little numbers which may or may not be there :rumour:

I agree with your figures by the way.

And If I'm wrong, I can blame it on failing memory due to advancing years.

Cheers,

Al.

fiat500 said:

Yes, it's all becoming clearer now. I now doubt that most people have actually set their engined up precisely, despite the warm words I have read about timing with a strobe.
I don't think that matters, but if you do use a strobe on this electronic distributor, you need to be aware of the significantly different timing mark you must make on the pulley.

Click to expand...

Peter,

Just a further thought. Some stroboscopic timing lights have an adjustment on the rear. This allows you to set the required timing figure e.g. 10* btdc on the timing light and use the tdc (0*) marks. In other words the timing light makes the pulley mark align with the tdc mark when the timing is set to 10*btdc providing the t. light is set to 10*. Same when checking full advance, set timing light scale to e.g. 28*btdc, run engine at e.g. 3000rpm or whatever figure you decide, point gun flash at timing marks and the pulley mark and the 0* mark should align.In other words the timing light is performing magic! So no need to calculate or make any additional marks on the pulley!
Snap-On and possibly others used to market such a timing light/gun but it was pricey. Might find a s/hand one now for not much money

Just something for anyone considering buying a timing light new or s/hand to keep an eye out for this useful feature.

Al.

Al those TL you are describing are magic as you said but not necessary expensive.
There are cheap versions at the bay. I have put it on my "wanna buy" list.

^^^ Thanks, Thomas.

If you happen to get one, please let us know how you find it in practice.

P.S. To me, anything with electronics or chips inside is magic!!

Al.

F123C said:

To me, anything with electronics or chips inside is magic!!

Al.

Click to expand...

There must be a silicon chip inside you then Al.
I don't need a protractor on the distributor because you were right on all counts. 9 degrees!
You're magic!

MAL_8582[1] by Peter Thompson, on Flickr

**further searching got me the answer thanks to Peter. So 36.6mm**

Old thread alert!!! But glad I found it so I could understand the reasoning for the 28 degrees advance on the 123.

So at the risk of sounding lazy, how far from TDC should I make a mark for 28 degrees? The timing light I have borrowed doesn't have the magic bit

36.60mm clockwise from the TDC timing mark/notch on the pulley.
Measure this on some very thin card which you can overlay on the perimeter of the pulley and then make a Tippex mark.

Fayray said:

**further searching got me the answer thanks to Peter. So 36.6mm**

Old thread alert!!! But glad I found it so I could understand the reasoning for the 28 degrees advance on the 123.

So at the risk of sounding lazy, how far from TDC should I make a mark for 28 degrees? The timing light I have borrowed doesn't have the magic bit

Click to expand...