Timing, Points, Dizzy, Pully marks

[Earthcruiser]

The all stock 72 240z (automatic) was running rough. So I replaced the spark plugs, sparkplug wires, rotor, cap, points (2-sets), and point lead wires (really rough shape) and condensors. Set the timing, no problems. I actually had it running well for one day. Then I drove to Zfest in denver. 50 miles each way. As soon as be got there, it started acting up. Started running really rough, backfired once, barely held an idle at stoplights. Got it home, checked the timing and it is about 20' retarded. If I attempt to adjust within the scale, the Z dies. It will not turn within the scale. I have checked the gap on the points, replaced the rotor and cap again, checked the firing diagram, all is correct. Any thoughts? I am stumped!

[Frankensteinz2]

You might want to confirm the scale by manually checking TDC, clickin it over till ur sure the number 1 piston is at the very top of the cylinder. Then check to see where u r at the scale. I have heard the pulley is sometimes off or can move.

Frankie

[theramz]

Check to make sure the breaker plate moves freely and returns. Check vacuum advance. It could be that the po solved the problem by tweaking the dwell and timing to get it to run but not very well. I think the a/t cars had dual points and an ecu that keeps the car from kicking down into first until it warms up.

[Ttiger]

And double check your dwell settings. If the points were not tight, they may have moved, changing dwell which changes timing.