123 Distributor / Setting timing Options

[rjames]

For those that have a 123 Distributor, I need some help setting my timing. I'm probably over thinking all of this but I've read several different threads on setting the timing with this distributor and I have interpreted them all differently.

I'm running a stock 2.0 w/ DJet.
The 123 distributor setting I'm using is 'B' (negative advance), and has a max advance of 22 @ 2700 RPM.

With my new-school timing light that allows me to set the advance, (with vacuum line from the tb plugged) do I:

- Set timing light to 27 advance and rev to 3500 RPM and time to the TDC mark?
- Set timing light to 0 advance and rev to 3500 RPM and time to 27 degree mark (same as above, right?)
- Set timing light to 22 advance and rev to 2700 RPM and time to TDC mark?
- Something else? (IMG:style_emoticons/default/rolleyes.gif)

I feel like an idiot asking this question. Timing is such a basic thing and I had no problem with the stock distributor and an old school timing light, but I've read more than one thread on how to time with the 123 distributor, plus I've also read that there's 10 degrees advance added at static on these distributors.
Help!

[DRPHIL914]

@rjames
@914_teener

after this thread got started i decided to revisit this issue on my car, being i had the height idle as well, once i used my timing light it says 1250rpm, anyway and some chatting back and forth on pm with these 2 fine gentleman, i thought i’d post my results from this weekend of testing and retuning .
I have been running the “B” curve and thought that was correct but looking back again at the book, my ‘75 diet has the 205B/021 distributor and that coincides with the “D” curve but i think either tB,C or D can be used here if you go with the retard vac line to the vac on the distributor.

while on that curve, over the past 2 years since i got the car back in the road i had an MPS fail, and had issues with getting my idle right. i have an AF meter, and i have no vac
leaks, engine has about 60k miles, i out everything new on this when i put it back in.
SO, all that said- rjames and i discussed this and looking at the programmed curves etc i decided to try C&D, reset
timing as see what worked better- i found that the B&D didn’t heel much different, and right now i am using the C , partly due to the max advance is at 3400, and it feels much stronger in the higher rpm range now. my idle is right about 850-950 depending on if my lights are on or not, it drops 100 with the current draw but is not steady and smooth- i still had an issue with idle being low for first minute upon cold start up(yes Aar is working perfect ) so i switched out my CHT to the new one from 914rubber, and this actually helped some, i could advance it some and that would help, i set timing at 22 not 27, but also i can tell you from charting my head temps that it is running cooler head temp now at this setting. maybe because it’s just a bit richer, or just the timing and advance change not sure but once warmed up it’s really right on the nose, 850 smooth
with lights on!!! yay!! one other issue, i noticed that my oil temps start to climb when it sits and idle in driveway for 20 minutes, gauge
says 230-240, wierd since i have an auxiliary oil cooler and fan , - soon ans i drove the car around the neighborhood it dropped
to 190, head temps at this same time we’re low at 240 while sitting there.
any thoughts on that???

i just wanted to share this here rather than a new thread as it pertained to what james us going on and figured it others were maybe interested and could comment.

Phil