Correctness of 123Ignition Advance Curves?

[twistedtree]

Has anyone verified the correctness of the advance curves in the 123Ignition distributor?  And if you have, which curve and what year was the car?  Vacuum advance or vacuum retard?

I ask because I installed a 123 in an old Volvo 140 and discovered that the programmed advance curves were very wrong.  Everything is programmed assuming vacuum advance, when the majority of the cars that the disti is meant for are vacuum retard.  The result is totally messed up timing.  It's like combining the wrong throttle body and distributor on our cars.  To get the thing to work you need to either disable vacuum and run without it which compromises performance, or modify the engine to re-port it for advance rather than retard.  123 is stubbornly ignoring the problem, much like they are ignoring the need for a longer spring in the W113 application.

I put a 123 in my '64 230SL and the car runs, but all I've done is back it into and out of the garage.  I no longer trust 123's advance programming, and want to verify it.  I'm curious if anyone has confirmed that the mechanical and vacuum advance works correctly, or are we all just taking 123's word for it?

[mbzse]

Has anyone verified the correctness of the advance curves in the 123Ignition distributor?

Well, they do publish the settings for the 123 equivalent to Bosch 051 distributor, e. g. Curve setting "8" in their M-B 6-cyl unit. See attachment  Would indeed be remarkable (note: could have chosen a more drastic term here!) if the product they sell would have a different spec compared to that published...

I enclose the 051 curve from the M-B workshop manual as reference, too

I am pleased with the 123, I run it in several of my sixties Mercedes and I have installed a number of units in friends cars as well.
/Hans in Sweden

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[twistedtree]

On quick inspection that looks right.  I sure hope the issue I've run into is unique to the Volvo distributor.  In principal I really like the 123, bought one for my 230, and would like to get another for my 280, but my confidence needs to be rebuilt, and I'd be hard pressed to buy another one if they won't fix the obvious and serious bug in the Volvo disti.

By the way, where did you get that advance curve?  One of my other frustrations with 123 is that they won't publish the advance curves, and instead leave it to their users to poke around in the dark when something isn't right.  They have told me to "try another curve" on the Volvo.  Wrong answer.

[thelews]

You can also buy the 123TUNE for slightly more and put in your own curve.

[twistedtree]

I agree in most cases, but my Volvo has electronic fuel injection and needs the trigger points that are built into certain 123 models.  Unfortunately, the 123TUNE is not available with the trigger points.  If it were, I could just fix the timing curve myself.

[mbzse]

.../...
By the way, where did you get that advance curve?

The 123 website, look under "123 Tune" and "Installation manual"
/Hans in Sweden

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[Cees Klumper]

I haven't checked the curve (not even sure what that is) but I have checked that the final timing advance is correct as per the BBB, just the other day (without vacuum, at 4,000 RPM).