TDC for 123ignition distributor????

[McBenz]

Quick question, do I need to set the #1 cylinder using the timing scale at "0" TDC to install a new 123ignition? OR do I set it to the recommended 35-38 degree BTDC from my old Bosch 051 distributor? The 123ignition instructions say "that before removing old unit, make sure rotor points to #1 cylinder and then remove and drop in new 123. Which I would think is actually the 38' BTDC. Am I really just not getting it ? Help and thanks.

[thelews]

I just put one in my 250 SL.  #1 should be at TDC on the compression stroke (piston at top of cylinder).  Timing mark should be aligned at TDC or 0, as you indicate.  This should enable you to start the car and then use a timing light to set the timing to 30 degrees @ 3K rpm, at least as indicated in my factory specs.

When I installed mine, I noticed my drive gear was not parallel with my rotor in the Bosch distributor as it is in the 123.  This meant the 123 was rotated about 20 degrees clockwise from the Bosch when installed.  Be sure to mark your wires and ascertain that the rotor is coming up (clockwise) on #1.  The firing, and therefore clockwise wire order, is printed on the valve cover.

Not sure if there are differences to the 280 vs. my early 250.

The car runs magnificently.  It ran very nicely before, I was just eliminating future maintenance with the 123, but I could barely feel the car idling at 800 and she revs very willingly.

[McBenz]

Thank you for your advice. I appreciate it. Looking forward in using the 123ignition. Did you install the Bluetooth version? Any recommendations to set Advance and Map Curves?

[dirkbalter]

Thank you for your advice. I appreciate it. Looking forward in using the 123ignition. Did you install the Bluetooth version? Any recommendations to set Advance and Map Curves?

I did the Bluetooth on my 280. There is what 123 calls a little "trick". PM me and I can send you the info if needed.
(Car runs great with it)

[thelews]

I did the Bluetooth on my 280. There is what 123 calls a little "trick". PM me and I can send you the info if needed.
(Car runs great with it)

I used stock merc-6-R-V curve 8

I don't really know how the car could run any better, maybe just allow someone a better dyno report.  But, my seat dyno says we're gold.

[dirkbalter]

I used stock merc-6-R-V curve 8

I don't really know how the car could run any better, maybe just allow someone a better dyno report.  But, my seat dyno says we're gold.

I wasn't looking for something special either. I just wanted to copy a 051 dizzy curve. But in the tune+ you have to program the points yourself. If you look at point # 5, it is set to 99 instead of 100 which is what 123 calls a trick to program the vacuum advance.
(To the best of my understanding)   
Car runs great with this curve. No comparison the my old (rebuild) 051 distributor.

[stickandrudderman]

If you look at point # 5, it is set to 99 instead of 100 which is what 123 calls a trick to program the vacuum advance.
(To the best of my understanding)   

That's not what I'm seeing in that image.

[dirkbalter]

That's not what I'm seeing in that image.

Ok. And what are you seeing?

[stickandrudderman]

I need new glasses!