123 ignition

[teahead]

Okay, I'm VERY HAPPY to say, that I got that sucker all dialed in (previous dizzy is an 062):

- black wire from 123 to (-) on the coil.
- red wire from 123 to (+) on the coil.
- bypassed ballast resistor (all red wires joining on one end of the ballast resistor)
- usage of above red coil with 1.8 ohms
- vacuum all hooked up
- about 3000RPM, running about 32 deg BTDC
- dizzy set to curve "E"
- removed/did not use spring on the bottom which the 062 used.


Observations:

- much smoother idle
- not as stinky (seems less rich)
- 95% of hesitation off the line GONE!  Once in a while, it's there but hardly noticeable now
- drives awesome!


Reason why I got my 123 is that the hold down screw on the 062 dizzy for the points is stripped and won't hold the points tight, so WTH, might as well get a new dizzy.  GOOD THING!

I highly recommend this to ANYONE still running points!  This 123 is wonderful! 

$$$, but worth it in my opinion for all the above, plus peace of mind.

 

[teahead]

One word of warning:

when installing the 123 (or any dizzy for that matter), COVER THAT POSITIVE BATTER POST!

I almost FRIED my new 123 because one of the levers/tangs to hold down the cap touched the post and it got RED HOT!  Almost melted!

[Shvegel]

Teahead,
I most likely have a used breaker plate for your 062 distributor that you can have.  I can check in October when I get home.  Definitely hang on to the 062 in case you want to switch back or restore it to 100 percent original.  Very expensive to repurchase.

Dan,
Don't most 1970-71 automatics have the speed diaphragm under the throttle body?  Wouldn't that give you manifold vacuum(As opposed to ported vacuum) if you connected there?  Should be able to tee right in

[dirkbalter]

@ Shvegel, The 70-71 throttle bodies don’t have that “manifold” vacuum port. In order to get it, you have to bore it out and press in a nipple. I had that problem too.   

[Benz Dr.]

@ Shvegel, The 70-71 throttle bodies don’t have that “manifold” vacuum port. In order to get it, you have to bore it out and press in a nipple. I had that problem too.   

I wouldn't do that. Any mistake could turn a valuable piece into a not so valuable piece.

[dirkbalter]

I wouldn't do that. Any mistake could turn a valuable piece into a not so valuable piece.

I agree. In my case I bought a 68 throttle body. However, I believe there is someone here in the forum that offers that service.   

[Tyler S]

Just a FYI, The “123 Tune” Ignition distributer does have provisions for creating your own map. This includes setting an RPM threshold for the vacuum and mechanical advance or retard to initiate. The only catch is currently it will apply to all temperature ranges. Hopefully the next round of updated 123 Tune distributors will take advantage of the already installed internal temperature sensor and allow temperature based events as well. This would allow one to completely bypass the OE switchgear on the late models.

[Pawel66]

I never understood this MAP curve. I have it, but I do not understand it.

[dirkbalter]

Just a FYI, The “123 Tune” Ignition distributer does have provisions for creating your own map. This includes setting an RPM threshold for the vacuum and mechanical advance or retard to initiate. The only catch is currently it will apply to all temperature ranges. Hopefully the next round of updated 123 Tune distributors will take advantage of the already installed internal temperature sensor and allow temperature based events as well. This would allow one to completely bypass the OE switchgear on the late models.

Tyler, I was waiting for someone making that statement. If I understand you correctly, the 123 will work without any vacuum input. All advance (or retard) is done based on the RPM.  At the time when I was looking, I couldn’t get or didn’t understand the statement I got from 123. 

[Tyler S]

Yes, Theoretically you could run straight "mechanical advance" based off of crankshaft speed but then you would not be able to take advantage of load based advance. Newer cars (meaning 80's and 90's) used a map sensor that always compared manifold vacuum to atmospheric pressure and advanced or retarded the timing based upon the measurment. The vacuum portion of the 123 could be utilized as such. A curve can be written to apply timing advance based on this input. the curve would look backwards from the 051 distributer curve. I will search around later to see what I can come up with.

[Tyler S]

Ok so I did a little experiment. My 250sl throttle body has a manifold vacuum port that is plugged off from the factory. Its about an inch and a half back from the throttle plate. (Like the port on the late system) I was able to unscrew the plug and attach a vacuum line to it. Then connected it up to the 123. I modified my curve to go from 0-11 degrees advance starting at 1000 rpm. This in effect mimics ported vacuum in that it is ignored until the throttle is depressed.  I drove it around the block a few times and all is well. It even has a better throttle tip in response. Reaches 38 degrees timing without issue. My next step will be to determine at what high manifold vacuum that the advance should start to fall off and end. This will come into play during decelerating.

[PagodaFest2019]

I have a feeling this will be an interesting "unofficial" tech talk at PagodaFest 👍

[dirkbalter]

Tyler, great information. As suggested, would love to discuss further at Pagodafest. 

[bracurrie]

Yes, Theoretically you could run straight "mechanical advance" based off of crankshaft speed but then you would not be able to take advantage of load based advance.

Tyler, I know this is an old thread, but I am researching dizzys and advance curves and this thread had much interesting information. For this novice, kindly explain why it wouldn't be ok to have the advance present no matter the load. Thanks

[Tyler S]

Brad, Under high load and RPM the advance is less critical. Its the light load (cruise) that you want the most advance. This gives you your fuel economy. So if you were in 4th gear at a low RPM, the centrifugal flyweight would not open enough to give you the needed advance. This is why they added a vacuum actuator to give advance under light throttle. When the throttle closes the timing is retarded. This helps with engine breaking and emissions.
Having full advance at all upper rpm load ranges was just a byproduct of the mechanical systems. It doesn’t hurt anything.

[Tyler S]

On another note, 123Ignition can now incorporate their electronics into your existing distributor, For those of you who are appearance minded.
However I would probably find a used worn out or broken core to do this mod and keep your original in a shoe box on a shelf somewhere.

https://123ignitionusa.com/custom-built-projects/

[edwardburak@erols.com]

what is number 29 in that picture?

[cfm65@me.com]

Hi Guys,
I recently installed a Getrag manual 5 speed as well as the 123 ignition dizzy, in my 250SL (Automatic).
Should I remove or disconnect the idle throttle switch on the venturi control unit?
Is there any thing else to remove or disconnect?
Much appreciated.
Regards
Chris

[Pawel66]

If you remove the throttle switch (which I believe you can do for manual car), you may want to install the cover with a gasket in its place:

https://www.sls-hh-shop.de/main/en/mercedes-230-280sl-w113-/07-mech-injection-air-intake-/07-a-injection-system

If you decide to sell this switch, I will be happy to buy it, provided I can afford it.

[cfm65@me.com]

Hi Pawel,
Thanks for the advice.
I’ll disconnect the switch and see what happens.
Let me see if I can find the cover, then you can have the switch.
I’ll be in the UK in a few weeks time and if all works out, then I’ll courier it from the UK.
Regards
Chris
Cape Town
cfm65@me.com

[Pawel66]

Thank you for your kind consideration.