Datsun Roadster Forum-311s.org

I recently rebuilt my 1600 and after installing it was having some tuning issues. A knowledgeable friend told me that my distributor drive shaft was off one tooth. I moved it and it got a little better but it’s not running right.when I drive it up and down my driveway it acts like it’s lean or has too much timing. Fuel pressure is good at 4 psi on the regulator. My 123 ignition distributor is telling me I have 30degrees crankshaft advance at idle but my timing light is only showing 15. When I change the ignition tune to 0 degrees at idle it then shows 15 degrees crankshaft advance but the timing light shows 0 degrees, this is all at 1K rpm. There has to be something off that I’m missing please help.
Will include pictures of my ignition map. I am not running any vacuum advance, if someone has a good static and vacuum advance map please share it would help allot. If you read this thank you.

I'm no expert, and I don't run a 123, but the distributor ordinarily runs off the cam. Crankshaft and cam revolutions are 2:1....I believe your timing light is telling you the conventional crankshaft timing, and it seems to me that 15º at idle should be okay. I've read about other 123 users having the same issue you're having, and had to adjust their map accordingly. Your map looks very similar to the one JT says he uses on the ones he sends out. JT, or others will probably chime in soon with help you can actually use. I just wanted to share what little I knew about it...
Mike

F, The distributor programming is in crank degrees. (It says so right on the screen shot).

This unit doesn't appear to be purchased from us, so all bets are off, could be a programming error, but I'll try to assist. (Ours are drop in and tested).

Sounds like your distributor is out of phase with the engine.

Fortunately, you can rotate the 123 360 degrees, so you don't need to reposition the drive gear. The correction is simple.

The easiest solution is to program and run a "calibration curve":

500 rpms 15 degrees (cranking)
700 rpms 20 degrees
5000 rpms 20 degrees
6000 rpms 15 degrees (6000 doesn't really matter)

So the "curve " is a flat at 20 from 700 rpm to 5k.

Now run the engine at 1000-2500rpm and rotate the distributor so that you have exactly 20degrees on the timing light and tighten the distributor in that position.

Now the distributor and the engine are in phase. 20 on engine = 20 on distributor

Do not rotate the distributor any more after this calibration operation. Leave it locked down.

Now program your regular curve. (or any othe "cal" points you would like to check)

you can verify 10=10, 15=15,20=20. Past 20 you need a dial back digital timing light to be accurate, but with that you can check total advance.

Good luck and thank you for your other purchases! Always glad to help!


(That is yet another great thing about the 123, since it will rotate 360 degrees in the mount, you really never have to change the drive gear position, just rotate the 123 where ever it needs to be!)

That worked perfectly, thank you so much!. I ended up being out 10 degrees which makes allot of sense why the car was behaving the way it was. Now the timing light and the apps crankshaft degree match perfectly.