SteveJ

From looking at the 73 wiring diagram, I would guess it has something to do with the seat belt buzzer, though the wiring diagram only shows 1 green & 1 black wire. Also, it should only buzz with the ignition in the ON position. If I am correct, the buzzing and lack of power are unrelated. Unplug the buzzer and use a test light to see if you have 12 VDC to ground on any circuits in your fuse box.

Here's my $0.02. How often do you get your car industry news from whichcar.com.au? (or motor1.com - the other site I've seen with this information)

Green is usually associated with the wire coming off the ignition fuse. It provides power for the turn signals among other things. I scanned various FSMs, but I did not see this connector. Please supply the year of the car you're working on. There are wiring differences between the various years. The device in question is a relay. I can tell that much.

Year? Photo of the offending part? Wire colors?

I could have sworn @Carl Beckbought a low rise lift for his garage that could operate with a drill and work underneath. I cannot find the post, though. I assume you have a garage, but I figure that being in Redondo Beach it wouldn't be a big garage. Edit: And then I found it: http://becksystems.com/garage/EZCarLift/EZCarLift.htm

You can get a copy of the 72 Owners Manual from Amazon. I provided a link.

1972 https://www.amazon.com/bishko-automotive-literature-Reference-Operator/dp/B00U2TTDNO 1973 https://www.amazon.com/bishko-automotive-literature-Reference-Operator/dp/B00AKLJFH8 (I bought this one a couple of years ago.) Please note that clicking on the link may cause a security error. You can search for these terms on Amazon to find the manuals: bishko automotive literature datsun

So SWMBO and I were watching YouTube and enjoying the Datsuns racing at Laguna Seca for the Monterey Motorsports Reunion. After the race, she glanced at the calendar in the kitchen and said, "We can now say ZCON is next month." Have you registered? http://zcon.org/conventions/2018/?page_id=132

I drove my car to a friend's house to do a photo shoot. ZCON attendees will have an opportunity to see the final result. On the way home, I glanced over at a barn at the corner of an intersection where I was making a turn. There was a brown S30 inside. However, I couldn't tell if there might be a house nearby that is owned by the car owner. I didn't feel like trespassing to leave a club card.

By the way, John Morton has been doing well in early running. He is running in Group 5. The cars that are faster than his are V8s, turbos, and cars with big wings & wide tires.

I got to see many of the cars when they came out here for the Mitty. You're in for quite a treat.

They should go down to the underside of the transmission tunnel to the reverse switch on the transmission.

If you are pulling through a dead pump, yes, it will reduce flow.

@dutchzcarguy is spot on. I installed adjustable 2 pin electronic flashers 3 years ago. No issues since. Plug & play. All you might want to do is adjust the blink rate. https://www.amazon.com/s/ref=nb_sb_noss_2?url=search-alias%3Dautomotive&field-keywords=2-Pin+Electronic+Turn+Signal+Flasher+Relay

A friend lost the clutch fork on his 280ZX track car at the Mitty this past April. It could just be a case of the 40 year old metal showing its age.

Sorry, Joe. I forgot you asked me about testing the tach without the car running. There is a way that I can think of, but it's not for the faint of heart. It would involve pulling the distributor (or using a junkyard distributor) and spinning it with a drill to provide a signal for the tach. There might be an easier test, but that will have to come from someone else. Usually, the tach pegging is not a good sign for the tach. (Example: https://www.classiczcars.com/forums/topic/20991-new-tach-problem-240z/) There are places that can repair the innards of gauges. This place is about 6 miles from where I work (though I haven't visited). http://www.hampspeedometer.com/

The gauge could be tested with the key in the ON position and engine not running. Use a potentiometer in place of the sender. If there is voltage going through the gauge, moving the potentiometer will cause the needle to move. Was the engine rebuilt? Was the sender removed/replaced? Are you sure all of the connections are correct? Do you have voltage to the gauge? How about voltage to ground at the oil pressure sender? Are the threads clean at the block and sender?

It could be. I was going off a post from one of the more respected members at Zcar.com. A little more digging revealed this size chart at Tire Rack: https://www.tirerack.com/tires/tiretech/45_conversionchart.jsp If the OP wants 15 inch wheels, the 205/60R15 should give a comparable tire size and not much speedometer error with the actual speed a little lower than the indicated speed.

You don't have to measure your tires per se. You just have to get the sizes off the sidewalls. (Note, that it has been pointed out in a different thread on this board that the wheel diameter can vary even with the "same" tire size.) Assuming that we're starting with a stock 175 R14 tire, I used 175/78R14 as the size. (Google is your friend.) You want a 15 inch wheel (There are not many good choices at Tire Rack, but if you don't mind the road noise, Advans are available.). This gives you available tire size (at Tire Rack) for 15 inch wheels: https://www.tirerack.com/tires/sizes/results.jsp?diameter=15

What size tires did you mount, and what is the size of the spare? There are tire size calculators that can help you figure the engine speed.

I used some Griots glass polishing compound on my 260Z windshield. It's very badly pitted and has some deep windshield wiper scrapes. It was a "it couldn't hurt" effort, and I couldn't see any difference for better or worse. Basically, from what I understand, most retail type glass polishing products are for extremely light scratches. If you can hook your fingernail on the scratch, it's too deep.

Been there, done that, have the marks on my cowl to prove it.

I haven't tried the conversion to a 260Z or 280Z distributor. I went with the ZX conversion in my 73. A PO did the conversion in my 74. The 260Z and 280Z used a transistor ignition unit (TIU) to control the spark. You would to need to figure out how to install a TIU into the car. Another alternative would be to use a GM HEI to trigger the spark. There is information online (including this forum) from people who have converted their cars to use an HEI module. I cannot say what would happen to your tachometer with either conversion. It may require figuring out how to adapt a 260Z or 280Z tach into your wiring.

Did you clean & lube the mechanical link before installing?