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Okay, I went into the electrical lab at work and borrowed a Fluke. with the Multimeter on Ohms, with the leads going red to black (left to right) on the two pins with the diode the Resistance is 23M Ohms with the leads going black to red (left to right) on the two pins with the diode the Resistance is 1 M Ohms I then switched the Multimeter to Diode Tester. Red to black or black to red the Multimeter read OL.

copy, that, I just read my new multimeter has a diode testor function. I will give it a go when I get home. Great Advice as usual SteveJ!

The two ways a diode can fail: Open or Closed. Open: Detection - You will see infinite resistance (OL) no matter what orientation you use with your meter leads. (Always try both directions.) Result - The alternator won't charge. Closed: Detection - You will see zero (0) resistance no matter what orientation you use with your meter leads. (Always try both directions.) Result - The alternator will charge, and the car will probably try to keep running with the key off since this will backfeed the ignition circuit.

okay, there is a diode in there, now I need to see what it would mean if the diode was in fact bad, and what that failure would manifest it self as

Try swapping the leads around where you got the open line. Diodes will block a resistance reading on a meter if you have the leads reversed.

interesting find. I checked the voltage regulator cap that you must install when you use an internally regulated Alternator. The 4 pins resistance was as follows. The two pins OL had a very dark patch on the back. I need to find out if there is a diode in there.

What kind of problems?

Well in Panama we have 91 and 95 octane ethanol free gasoline. My car has the original manifold. I only have heatshield installed under the carbs. Maybe its time to consider ceramic coated headers. Thanks for your advice.

$25,500 For instance, Less fees. Not a chance IMHO. Sell it privately to someone that’s going to preserve it.

All I know about the 60amp internal regulator is I also have it. I think this old thread shows the wiring diagram that is implemented with Dave Irwin's upgrade. 240z alternator upgrade (instructions w/ pictures) - Electrical - Classic Zcar Community

Where did you take the alternator to be tested? If you don’t have someone at a parts store that’s competent on testing you might want to go to a local Napa store or an establishment that has a machine shop. Counter people look at a screen and most don’t have experience on working on vehicles. My HO. Ok I vented. Wish luck friend.

I would think BaT with a healthy reserve. I wouldn't consider a no reserve auction, too easy to lose it cheap.

Now I have no idea what the test read, as it only comes back with a big green check. No voltage out put was displayed. According to the 72 Z wiring diagram the red/white wire runs back to the fusebox, so that seems like it should be supplying the car with power after the car starts. My problem is that the wiring diagram shows the voltage regulator and I am running an internally regulated alternator. So I have to figure our which wire it is that should be charging my battery and which is supplying the car with power (me thinks red'white)

The alternator tested a big green check at the parts store. However, I tried to test to find any out put from the T connector while the alternator was running well I got nothing, but it would see that it fried my volt meter LOL LOL. I am sure I should have measured the red/white wire from the back of the alternator instead. But now I have to get a fuse for my voltmeter or a brand new voltmeter... which would not be horrible.

https://bringatrailer.com/listing/1972-datsun-240z-358/

I did but to no avail. I even ended up blasting the old grease/dirt out with brake cleaner and then relubing it with sprayable silicone lubricant but the squeak didn't go away

I'm wondering the age window myself. How much longer will people be interested in a 1972 Datsun?

The alternator test at the parts store?

By chance did you try a cleaner and spray able grease before you removed it. Trying to understand the process you went with.

Okay update All fuses are okay. One of the female spades in the "T" connector has 12.7 volts with the key off. The key in the Run position reads 11.8V but that also powering a electric fuel pump, so that is fine

I converted to electric fuel pump in my '71 Z and left the return fuel line in place. I figure this helps keep the fuel cooler because the heated fuel that doesn't get used in the carbs is returned to the tank which is cooler than the engine bay. I figure this allows more cool fuel from the tank to flow to the carbs. Also if it's available in Panama you should run ethanol free gas. The ethanol free I use is 88 octane and the car runs just fine. If you don't have ethanol free you should probably run premium. I do have ceramic coated headers and the heat shield under the carbs and I've seen my temp gauge get up to close to half way between the middle of the gauge and the hot side and didn't vapor lock. The weather here runs in the 90's (Fahrenheit) to 100 in the summer. As you've experienced, heavy traffic with lots of idling will heat these cars up!

Zedy…..Glad to see you still wearing your steel toed safety socks!!!!

Namerow, You are probably right. Ive spent so much money in parts and mechanics in Panama. Luckily, after 11 years of having purchased this car, this is the first mechanic who got all 6 spark plugs tanned correctly due to PCV valve not working correctly. I still have my theory of vapor lock and will remove the a/c condenser and fan i previously installed for the AC in my car. Do you think i need to leave the gas return line open for the car work better. (Airtex 8012S electric fuel pump)

Worry not my good man, your words of advice will not go unheeded. I will check out those parts this evening when I get home. A simple Alternator test is just one more part of the equation. It is simple and free.

I have seen the diode fail open in that design before. That would keep the car from charging. Also, if the ignition fuse in the fuse box is blown, it won't charge. The test I asked @Zedyone_kenobi to perform would help to identify those problems.