123 Ignition Help Requested

[The Hawaiian]

I have a problem that is confusing the heck out of me:  After setting the distributor per the static setting procedure, the car will not start.  The car will only start after I turn the distributor to about 50 degrees BDTC.  Yes I am using the correct scale for the timing marks.   I've checked the cam shaft positioning to the timing marks and it is about 6 ADTC, I've set the valve clearances, I checked the relays, and see that vacuum goes away at about 2400 RPM. 
Plug wires measured as follows:
  Coil to Distributor:  13K and I changed it to a solid core wire and now has about 0 ohm
   #1 Plug:  5.2 K ohm (angle plug – I know it is wrong after searching this site for answers)
   #2 – 6 Plug wires:  1.2K ohms
New spark plugs gapped at .035” - went with the hotter spark plug - NGK BP5ES
Rotor:  5.5Kohm NEW
1.5 Ohm 45K flamethrower coil NEW
All external starting and running resistors and transistorized ignition box removed – coil positive side is getting full voltage.  Negative coil connected to the black wire for the distributor and the proper relay to operate the speed relay.
During running I get consistent voltage on the low tension side of the coil. 

Even with timing at 50 degrees I have erratic sparking.
Comparing the internal position tabs (part that mates with the motor) and rotor position between my old 062 distributor and the 123 distributor I note that I have about a 50 degree differential for the rotor when the internal petitioners are aligned

I even changed the plug wires to the next connection in both directions on the cap and had no luck.

I know that the car runs a rich but not eye watering rich.  I had a miss that appeared to be the transistorized ignition box so I thought it would be a great time to change to the 123 ignition distributor.  Previously my old distributor had normal timing - 30 BTDC at 3000 RPM and about 2 ADTC at idle with vacuum.  This has been a hard install.

Is this a problem with the 123 distributor?   Has anyone seen this problem before?  I appreciate any suggestions.

Norman Howard, The Hawaiian
1970 280SL

[Flim]

Aloha Norman,

I feel your frustration as I had a similar problem installing a 123 ignition on my 250 SL two years ago  . I had decided to upgarde to an electronic ignition at that time for the improved reliability and simpler maintanance that it offered despite the car starting and running ok with its 051 distributor.

I had a similarly terrible time ''dropping'' the 123 ignition in due to the following issues and how I overcame them:

1.With the engine set at TDC/ roughly the static timing mark (only one scale of timing marks on  my 250SL) the rotor arm on my 051 distributor pointed to number 1 spark plug.
With the 123 distributor dropped in and engaged (it'll only go in one way due to the offset key) its rotor arm pointed to roughly the nut on top of the power fluid steering resevoir (about 50 degrees out?)

I re-arranged the distributor cap so that the first spark plug wire that the rotor arm would contact would be number 1 and the subsequent wires inserted in the correct cylinder firing order as cast on the rocker cover (1-5-3-6-2-4 from memory, or is that my secret bank account password?? )


2. The 123 instructions describe how to obtain the static timing by rotating the distributor until the static timing light just turns off, but I similarly found that my car would not start at with the 123 set at this point. On examination I found the rotor arm to be way advanced from the number 1 spark plug lead at this static timing point so I simply rotated the 123 until it was very slightly advanced from number 1 spark plug lead and with an assistant to turn the engine over on its starter  motor, I rotated the 123 very slightly clockwise and anti-clockwise until it started.
I then used a strobe light to check and adjust the ignition timing as per the haynes manual (there wasn't much in it).

The car has starting and running perfectly since with a steady even idle at 750 rpm, and accelerates without hesitation  . It was well worth the hassle.

I am still not sure why the 123 distributor cam is offset in this way (it cannot be adjusted, believe me I tried!!) but I'm sure that you should be able to get started again.

I hope that this can be helpful.
Charles

[mbzse]

A number of good tips about procedure to fit the
123 distributor unit into a vehicle can be found in this thread
http://www.sl113.org/forums/index.php?topic=9984.0

If you insert a big, flat blade screwdriver into the mounting hole for the distributor,
you can turn the dog tooth drive down there, so that you get your 123 distributor rotor
finger to point at No 1 cylinder

To begin with, ensure that crank shaft is at "0" (TDC) and that camshaft is in a position with the
two lobes for No1 cylinder pointing up (10:00 and 14:00 on a clock face).

Modify the mounting clamp, otherwise the 123 can not be fully inserted
(unless you have a late 280SL)
/Hans in Sweden

.

[The Hawaiian]

Thanks for the response.  I tried the swapping of the leads as you suggest without any luck.  Using the TTS method of cranking with the ignition on, I am able to crank the engine while turning the distributor.  What I did not have was experience what a proper spark looked like.  I've also verified static tiiming (10 degrees BTDC) and verified correct based on camshaft lobe position for the #1 cylinder exhaust and intake valves.  Additionally, for my engine, the dogs are ever so slightly off-set so there is only 1 real way to install the distributor.

To update everyone.  I put the old distributor back after figuring how to run a 062 distributor as a regular points dizzy without the ignition box.  Compared the spark at the plugs between what I was getting with the 123 dizzy and the 062 - night and day.  It appears that for some reason, the 123 dizzy has an internal fault and the spark is so weak that it required 50 degrees of advance to have the flame front spread after the spark plug firing to develop power.  So with the temporary system it was instantly smoother and timed at the correct point.  This was only temporary for testing as it will likely burn up the points..  

Will have to see if I can get warranty work done on the dizzy.  If that takes a while does anyone know which Pertronix system would fit in the 062 distributor.  Research indicates that no specific system for the 062.   A search of forum topics indicate that an 1864LA may work physically, but I've seen 1863 and 1867.  I am looking for a temporary and EASY swap until the 123 distributor comes back.  This is car is a daily driver and my family is loosing patience as the car has been a garage queen for the last couple of months as I've been troubleshooting.  This has been a learning experience about our cars - one day I may say it was a great learning experience.
Norman Howard