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Discussion Starter #1 (Edited)
There is alot of information about the 123ignition distributor scattered through a number of threads. I decided to sum up my experiences after 22 months and 15k miles of use.
This is the distributor that is sold by IAP for a little over $400. It is also available from some of the European Alfa parts places and it may be worthwhile checking them out if you plan to purchase. Keep an eye on the exchange rate and shipping costs.
I installed mine on my Spider in December 2007. It is a fairly hot motor with:

ported head (standard valves) by Richard Jemison
RJ136/785 cams - the same as or similar to the ones in Andy Besic's 200+ HP race motor
10:1 Motronic pistons
Weber 40DCOE116/117 carbs with 34mm venturis and Euro airbox
Shankle headers

The best part about the 123 is that the advance curves are accurate. I think that the claims for stronger sparks are questionable as it cannot be used with a low impedance, high energy coil.

The blurb lists 16 selectable curves but in reality there are "only" 8. Of these 8 distinct curves, 3 of them are for 1300 & 1600 motors and 5 are for 1750/2000 motors.

The Marelli 103B curve #F is very similar to the Bosch 0.231.178.006 and I doubt that anyone would be able to detect much difference between them, so there are 4 distinct 2L curves. I tried them all.

The Bosch 0.231.178.006 curve #A is a slow curve intended for low emisions. It enables a slow steady idle but produces mediocre throttle response and fuel consumption. It may be a good choice if you want to run on lower grade gasoline.

The Bosch 0.231.110.045 curve #1 is the standard Alfa curve for Euopean, carburetted cars. It is a good compromise curve. Decent throttle seponse, good idle and fuel consumption and slow enough to accomodate a lot of high rpm advance. I ran this curve with 40 degrees full advance with no pinging on 91 octane gas.

The Shankle 4255 curve #E has the best throttle response. The problem is with the idle. The curve is so steep in the 800-1500 range that the idle either climbs to about 1500 rpm or drops to 700. It is difficult to get it to idle at any rpm in between and I had to almost stall the engine to get it to settle at 700. It is a shame since the performance between 2000 and 3000 is outstanding.

The "006 tuning" curve #D is the Jim Karamalakis curve. It seems to be the best choice for my engine. The idle is easy to adjust since the curve is flat at 1000 rpm and the throttle response is good, if not as good as the Shankle.

The 123ignition website says that it is not compatible with electronic ignition boxes. This is clearly incorrect. I have mine hooked up to an MSD 6AL box. It fires a Milano, low impedance coil. I have the spark plug gaps opened up to 040". I expect that it is also compatible with Crane spark boxes.

I am very happy with this setup. My engine as considerable piston blowby and fairly high oil consumption. Plug fouling has been an issue for quite a while. The sparks from the 123/MSD combo are strong enough to prevent most of the hesitation that I had previously encountered. The engine revs easily to 7500 rpm and appears not to be limited by the ignition.

The distributor is well made but you need excellent eyesight or a magnifying glass and good light to see the curve selector switch.

IAP imply that you can set up the distributor using only the "P" mark. This is true if you have a variable delay timing light, but this is also true for any distributor. It is necessary to mark the pulley with the correct "F" mark for the curve of your choice if yopu are to use the static timing method. I always check the timing at maximum advance as I have found that the static timing methods usually produce errors.

I recommend the 123ignition distributor to anyone who wants to get away from the vagaries of centrifugal advance mechanisms. It is a big improvement on the Shankle/Marelliplex that I had before.

Edit: Attached data sheets for all advance curves
 

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I just wanted to say "thank you" for your well organized and informative post. Most helpful and when I get further into this topic I may be looking for some more help (new 1750 coming). Nice job!
 

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Kudos to alfaparticle for an excellent write-up (I know I printed it off and filed it). I'm hoping Ed (or anyone for that matter) might give me some advice for my situation?

1969 1750 Spider (European spec. with euro cams, Bosch ...041 JF4 distributor, etc.), completely stock other than a recent top-end re-do (new guides, valve grind, etc.) Strong engine.

Have purchased the 123ignition to replace my Pertronix-equipped Bosch distributor as the rest of it is just worn out and would not let the idle come down at stops unless you try to stall it with the clutch.

Can't figure out which advance curve setting to use. The "M" mark on my original pulley measures out at 43 degrees (2-4 degrees static), which is backed up with a chart in an old Alfa Ricambi/Shankle catalog. Seems awfully high.
Do I go with any of the settings #4 through #9 (all the same as far as I can tell) or go with the 045 setting (#1), or try the "006-tuning" one (D). I am still a little fuzzy on how different advance curves affect the everyday characteristics of an engine, hence my hesitancy.

Would going with the 006-tuning curve be okay on an otherwise stock 1750 (albeit a European model)?

I have a replacement Spica pulley on my engine (the 1750 one cracked in the keyway) and I just finished putting marks at 43, 40, and 38 degrees as I get ready to install the 123.

Any thoughts?
 

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Discussion Starter #6
I would try the 045 curve first. The choice of max advance is yours. I suspect that you will be able to run with 43 degrees without pinging. For my pinging tests I filled the tank with 50% premium and 50% mid grade. That gives me some safety margin as I normally run on premium. I gave it WOT at various rpms in 5th gear. If it going to ping it will most likely be in the 3000 to 4000 range.

You probably don't need the 006 tuning curve unless you have long duration cams.
 

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OK so here is a really stupid question. What is the benefit of running the MSD in addition to the electronic distributor over just the electronic distributor without the MSD? The coil is the same in either case, right? So is the MSD somehow conditioning the spark in some way that is beneficial? Would I be likely to notice this on a stock engine? Thanks!
 

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Discussion Starter #9
I thought that I explained that in the first post. The 123 will not fire a low impedance, high energy coil.
 

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OK alfaparticle thanks for the explanation. I obviously missed that part. So I guess the MSD is acting as an electronic switch? The magnetic contacts in the electronic distributor trigger the MSD which in turn connects the high energy coil to the sparkplug? Sorry to be so linear here but I'm trying to understand exactly what is happening in the circuit. Thanks.
 

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Curves for smaller motors

Since this seems to be the go-to thread for 123ignition info I'll resurrect it rather than start a new thread.

Ed's given a lot of great info for 2L motors. Anybody have any info on the smaller engines? I just got a 123ignition for a hybrid 1600 / 1750. That's a 1600, bored out for 1750 pistons. It's mostly a stock motor, with the late 1600 / early 1750 cams, stock valves, but with substantially higher compression due to a head shaved about .050.

Oh, and just to add to the equation, I'm using the stock 2 bbl Giulietta manifold with a Weber 28/36 DCD. Any general ideas before I just start playing around? I'm still waiting for a few bits and bobs before I can reassemble my engine, but thought I'd solicit feedback before I get started.

-Jason
 

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As part of my Spring Tuning plan, the 123 will be installed on my Spider--soon.

Looking forward to the results.:D

Gordon Raymond has some advice on changing the intake manifold on single carbs that provides outstanding results.:cool:
 

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Discussion Starter #14
Four of the curves are reproductions of Bosch distributors for 1300/1600/1750 engines. I would start out with one of them. They typically provide more maximum advance for the same static advance. Your higher compression ratio may require less maximum advance. The 123 is nice because you can try the different curves and see the difference.
 

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Four of the curves are reproductions of Bosch distributors for 1300/1600/1750 engines. I would start out with one of them. They typically provide more maximum advance for the same static advance. Your higher compression ratio may require less maximum advance. The 123 is nice because you can try the different curves and see the difference.
Thanks, Ed. I was hoping you would chime in. I think I'll start with the 4-9 curve and dial it in from there.

Best,
Jason
 

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Discussion Starter #16
That curve provides 37 degrees of advance at 4900 rpm. Someone posted the curve a few years ago - probably Jim Neal.
 

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123Ignition & Crane XR3000?

Has anyone successfully paired the 123Ignition with the Crane XR3000 ignition module and, if so, could you share a wiring diagram? The Crane has a 3 wire molex plug (wires are white, gray & black) that's intended to work with their optically triggered distributor. The 123Ignition has two wires - red & black. I'm wondering which wire is ignored and which two are used.

Thanks,

Mike
 

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Richard Jemison
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Crane unit

It will not trigger the 3000 series Crane (bottom of the line)
It will trigger their better units that have inputs for both type electronic signals.
 

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Another 123 Believer

I replaced the stock 80-81 retard-advance Marelli-Plex distributor and coil yesterday with a 123 distributor, a Bosch high energy coil, and Lumenition silicone wires ( all sourced from Classic Alfa in the UK for less, including shipping, then the same distributor alone here in the US). I set the advance curve to 045 and on my first test drive I found a very noticeable increase in power and drivability throughout the range, and I have yet to retune the carbs (will get to that today). I am very pleased with the setup. What a difference a decent advance curve can make!

It should run even better once I get the RJR cams I ordered installed...can't wait! :D
 
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