SteveJ

You measure valve lash with a feeler gauge. While there has been plenty of debate online about doing it hot or cold, you're definitely doing it cold. I hope your mechanic used properly sized lash pads. Use 0.008 for intake valves and 0.010 for exhaust valves.

If you still find them, Chevette springs can be cut to height. For some reason, there aren't a lot of choices available for a 40+ year old econobox. They give a much firmer ride, but I don't find them harsh or too stiff. The nice thing is that you can get 2 pairs of springs from Rockauto for $88 plus tax & shipping. The flip side is that you have to be willing to experiment to cut the springs the to right height. From re-reading the thread linked below, I guess I was aggressive with the amount I cut, but I'm happy with the results. I cut 3 from the rears and 2.75 from the fronts.

Pages BE-13 and BE-15 in the FSM cover these circuits. Common points of failure are the fuse box, the steering column connector connector where the green/blue and green/white wires pass between the dash harness and combo switch, and the combo switch. Unplug the steering column connector and check for voltage to ground at the green/blue wire on the dash harness side. It should always have battery voltage. Also examine the connector carefully for signs that it has overheated. I've seen many meltdowns at this connector. If you don't have voltage to ground, go back to the fuse box and test the voltage to ground on both sides of the fuse. The loose wires in the first photo are for the key buzzer. I'm not exactly sure where the second photo was taken, so I can't give an answer on those wires.

Where did you tap into for the voltmeter signal? There's a blue/red wire coming off the ignition switch and goes to the fuse box. It goes to the radio fuse coming out as a blue wire and the wiper fuse where it comes out as a blue/red wire. I'm guessing one of those wires, probably the blue wire is the signal for your voltmeter. If the blue/red is having intermittent contact to ground but not enough to blow the fuse, it could pull down the voltage on both circuits. Unfortunately you can't just pull the fuse for the wipers as that will also kill power for the reverse lamps.

It's the same part number in the parts catalog.

"Locking" means it is locking out the power switching circuit, so the coil never gets grounded. This is similar to why you don't want to leave the key in ON with the engine not running when you have points, only you are protecting other components.

And you can get them from a Nissan dealer, too, if you order part number 90522-E4100. https://www.courtesyparts.com/oem-parts/nissan-stopper-t-gate-90522e4100

Vintage connections has some good replacements for the connectors that use the spade style terminals. The round terminals for the gauges and dash harness to engine harness connectors were made by Yazaki (I think the spade connectors were, too.). Those connectors seem to be made of unobtanium, though you can get the terminals with different connectors from Eastern Beaver.

You don't have to go all redneck with spade lugs. You can get a replacement connector from Vintage Connections. But make sure you run the one test that I suggested. Have you looked at the C-5 connector?

To @Zed Head's point, you could take the black/blue wire off the ballast resistor, tape it up, and check the voltage again.

Is this what you're referring to? https://www.thezstore.com/page/TZS/PROD/34-1152

Then if your technique was good, that might indicate wear within the ignition switch. Did you order the full switch with key or just the module in the back of the switch?

And even when it's bad, it can be replaced by a GM HEI module pretty easily.

The switch contacts should be pretty close to zero. The resistance at the ballast resistor is fine. You don't want the resistance to be too high because that would be a voltage drop. It does appear that you are losing voltage somewhere, depending upon where you measured the 7.2V on the black/blue wire. Was it at the resistor or the ignition switch? Again, look for corrosion at the connectors for where the dash harness plugs into the ignition switch.

This sounds like a great time to shoot some video when trying to start so we can see what is and is not happening.

Overhead shot of the magnet placement

Sorry, I didn't mean to confuse. This thread may help some.

Maybe this will help. This is the timing mark on the 240Z with the distributor as reference.

Did you confirm that it is on the compression stroke? Did you reorient the oil pump & distributor, or was it oriented like that when you got the bunny ears on the camshaft on cylinder 1?

One funny thing happened while I was taking photos was that I was stopped after taking a picture of the Porsche below. The owner wanted me to feel his headlights, and it wasn't even a dirty proposition. As I walked over to his car, I said, "Oh, do you have the concave headlights from Cibie?" It surprised him that I figured it out. I let him know the concave Cibies were valued in the Z car world. It's great when different parts of the car loving universe can intersect.

Well, I haven't been driving the Z much lately, but the weather looked good for the Worship meet today. Worship was started by people who thought our local Caffeine and Octane show was getting overwhelmed by non-car people. I like going because people don't care that I don't have a show car. They are more than interested in the modifications I have made. It was cold starting out, and it took a while for people to show up. There were only 2 other 1st gen Zs there, plus a 350Z. One of the highlights for me was when a guy in a Cayman drove up with his German Shepherd. As soon as he opened the door for her, she made a bee-line straight for me. She was such a sweetheart. It was a good sized crowd eventually. Just to prove I didn't have the only Z there, here is my friend's Series 1.

I appreciate your willingness to go back and test. Let's look at the coil and work back. Fortunately, it's not that difficult to trace. For stock wiring there should be a white/black wire from the coil to the ballast resistor. There is a black/blue wire attached to the ballast resistor on a different terminal. The black/blue wire goes to a 3 wire/4 position plug and through the engine harness to connector C-5 where it stays black/blue going through the dash harness. The black/blue travels over to the ignition switch where it is energized when the key is in the start position. So what could cause the voltage to drop? The ignition switch could be wearing out. There could be corrosion at one of the three connectors There could be a bad connector at the ballast resistor or failed ballast resistor. So what can you do to test? Measure resistance at the ballast resistor between the white/black wire and black/blue wire. Alternatively, you may want to test the voltage to ground at the black/blue wire at the ballast resistor with the key in START. If it's 12+, then it's probably the ballast resistor. If it's low, you know it's before the ballast resistor. Visually inspect the connectors. If they need to be cleaned, a little vinegar on a q-tip can clean off corrosion at the connectors. Disconnect the connector on the back of the ignition switch and test the resistance with the key in START between the terminals where the black/blue wire and the white/red wires would go.

Check the voltage at the battery while cranking. I'll bet it's pretty low, too. You don't say how old the battery is. Maybe you did earlier, but I'm not going back to see. The plates could be sulfated, they can still have adequate voltage while sitting, but they don't have the surface area for the electron flow needed during cranking.

For the Crane, red goes to coil positive and yellow goes to coil negative. The black/white wire that is hot when the key is in Start or On is on the coil positive. Why is the green wire on coil negative? It would either go to the distributor or to the TIU. Neither one is in service, so it could be pulled off the coil negative. Has the TIU been disconnected? It doesn't work with your (@mayolives) setup anymore.

Here are some suggested steps. Some of these I have already provided. Disconnect C-9 and check resistance on the alternator side of the black fusible link to ground. If the resistance went up, go to #5. If you still have low resistance, disconnect all of the white/red (W/R) wires (including the one to the condensor). Measure resistance at the fusible link again. If the resistance at the link went up, check resistance to ground at your alternator where all of the W/R wires were connected. Otherwise, you likely have a problem in your wiring harness. With C-9 still unplugged, measure resistance from the (W/R) to ground. You can do that at the fuse box. Just select the right side of any of the fuses I circled. If the fuses were in the fuse box with high resistance, remove the fuses and measure again. If the resistance is still high, unplug the ignition relay and measure again. Record your results, and also take photos. As for the wiring at the coil, is that an I91, E92, or E93 coil? I recognize the red, yellow, black wire bundle as probably being from a Crane ignition system. It makes me wonder what distributor is in the car, since the Crane optical trigger was designed to replace the points, not a reluctor.