Zed Head

Also, your title probably shows your 260Z as a 1975 260Z. That always causes kerfuffle on the Z sites. https://www.hagerty.com/articles-videos/articles/2018/10/23/what-to-look-for-in-a-datsun-240z-260z-and-280z

No real thoughts, just like a good puzzle. This chart shows 11/74 as the last "production date" date for US market 260Z's. Interesting. Maybe the stamped number is added when the VIN is assigned. 11 is pretty close to 12. You might have the last produced US market 260Z! Your VIN is about 9,000 higher than the last VIN they show also (edit - I was looking at the wrong line. 1975 260Z's go up to 200000). No idea where the chart came from. https://jdm-car-parts.com/blogs/news/vin-verification-of-us-datsun-240z-260z-280z-280zx

So shiny... I want to touch it with my greasy fingers too.

Could get even more expensive if your cores are no good. Time vs. money vs. convenience. He says the MC and booster are "new" but then he requires cores. So they're probably rebuilt. Many of the Rockauto and other auto store reman parts available today are of low quality though. So, you kind of need to have a vision in mind of what you want the final product to be like. https://zcarsource.com/core-disclaimer/

Sounds like it's lean in that RPM range. There's probably an adjustment possible. Don't know how the Webers work. Should have put Weber in your title.

Nice. Didn't even have to remove it. I wonder if Mark meant braze when he said weld. They're similar. You can probably accidentally braze when you meant to weld also. Be interesting to see how it holds up. If you didn't pin the ends with drilled holes, as suggested, the crack might just continue to grow from the ends. But they'll be small cracks. https://www.machinedesign.com/fasteners/when-brazing-beats-welding https://www.lucasmilhaupt.com/EN/Brazing-Academy/Metal-Joining-Welding-vs.-Brazing-vs.-Soldering.htm

Check your glue blobs. If you have a meter, measuring resistance of the coolant temperature sensor is easy to do also. Working on the EFI system is really just taking measurements and comparing them to a check list. Measure-check-measure-check.... If you get a bad measurement, you find the cause and fix it. When all of the measurements are in-spec. if the problem still persists then you go to the weird stuff. Often-times people adjust things to out of spec. trying to fix other out of spec. things. Forgot the glue blobs picture. Post #29.

I wonder where Nissan was getting the red ones? They don't seem to have a part number on them. Anyway, good to be back to normal and verifiable. All links should have a Nissan part number stamped on them. The Atlanticz page still suggests that red is 069 mm^2 though, so beware. The zcarsource pictures show a 1.0 link, not 1.25. And orange 0.35. They might get theirs from Japan but not necessarily from Nissan. Plus they say that 1976 is the same as 77-78, which is not right (look at "Additional Information" on their page). I'm just reacting to all of the words and pictures that are out there about fusible links. Lots of variation and confusion. https://zcarsource.com/fusible-link-cover-set-280z-76-78-new

Nothing specific to SU's but my understanding of "run on" or dieseling as we used to call it is that it's caused by hot spots in the combustion chamber. Why it was called dieseling. So, he either has dirty combustion chambers or sharp edges that are staying hot. High cylinder pressure would be more susceptible to dieseling. The common way to avoid it was to rev the crap out of the engine just before shutting down to blow all of the carbon out and get some fresh cool fuel and air in there.

Aren't these 240Z brake parts hard to find? You guys are making it sound like it's a simple go to the store, swap the parts. Especially the Master-Vac. Might be worthwhile to disassemble it and seal any small tears in the diaphragm before they get big. You know that brake fluid has probably been in there, the paint's peeling from the bottom of the booster.

Congratulations. The brakes might just need bleeding. The switch, cleaning. Have fun. My spare tire comment still holds....

Just remembered that 77 has the space saver spare tire. Comes with a canister of air, to fill an expanding rubber tire, made of 40+ year old rubber. Most people switch to a smaller import "real tire and wheel. That is one thing that might be a trip killer. Flat tires are common. I don't know that I'd trust that tiny expanding thing in the spare tire well. Has anyone ever actually used one of those, after 40 years? Maybe take a can of "Fix-a-Flat".

Inner and outer. http://www.carpartsmanual.com/datsuns30/Datsun-Z-Index/Axle/Front-Axle

The next simplest test is to check the vacuum hose from the FPR. Give it a twist to break it loose before pulling it off. If you only have a short time to mess around. If it's wet with fuel, you'll need another FPR before continuing with your other tuning tests anyway. Edit - forgot to say that you can still get proper pressure readings with a leaky FPR. You just can't see the extra gasoline.

I vote for go for it. Watch the gauges. Don't let it overheat. Make sure the alternator is charging. Stop and check fluids every hour or two. It will be an adventure for you and your future wife. Stories... Too soon to be mundane. No offense to the cautious folks. There are probably some Z oriented shops along the way. Get their info and make the trip during business hours.

The spacers match the hubs and are designated with a latter showing the size range they are in. Most hubs are the same, "B" I believe. Check the letters on your hubs. If they are the same then mixing up the spacers just moved the play from one side to the other. So swapping them would just move the play back to the other side. A better way to make sure things are right is to measure the spacers and the hubs before assembly. And the axles do have some play. About 6 thousandths.

You can use points to drive an MSD or Crane electronic ignition. And there's always Pertronix, they have a better ignition module that gives high energy spark, the Pertronix Ignitor II. Many options. Not surprised that you found a broken distributor. Most of us have.

Only responding to what you wrote. Good luck.

The idle air bypass screw is under the rubber plug on the side of the AFM. It is used to lean out the idle mixture by letting air past the AFM vane. In later years Nissan put a solid cap over that screw so it couldn't be adjusted. But 1976 still made it easy. It's a fairly easy and common adjustment for idle. Not sure I'd read too much in to it for your year. Didn't realize that the car was not driveable. You said that it smoked, and died, but it seemed like it was repeatable after eventually restarting. Now you say it's "not running!"? Anyway, good luck and don't expect a miracle cure. You'll probably have to check a lot of things that check out just fine before you get to the one that isn't. "The car has not been running much at all for 2.5 months, I drove it a whopping total of 4 times....... mostly neighborhood drives less than 10-15 miles aside from the 75 miles drive home after initially purchasing it. I have not had a chance to beat on it, I would like to really drive it.... BUT IT'S NOT RUNNING!"

All I'm saying is don't make things too complicated. It passed emissions in California, which is difficult to do. I'd be surprised if the days of the shady smog guy are still in play these days. The fines for doing that are huge as I understand it. Beside that, the car has been running fine for 2 1/2 months, when, apparently, a problem "suddenly" occurred. A shady mechanic can't make a car run well for just 2 1/2 months. The seller of the car probably sold you a good car. Something small and simple is probably broken or stuck. Have you been beating on it? Taking it up to redline, banging through the gears? Have you been maintaining it properly? Has it run low on oil or coolant? Have you been adding "wonder chemicals" to the gas tank, like Seafoam? Once you get the EFI systems back in spec. they're pretty steady. They don't need constant attention. Watch the oil and coolant levels, put gas in, and drive it.

Why did you show the old plugs from before the tune-up by the Po's mechanic to pass smog? They don't tell you what's happening now. If the PO's mechanic got the car to pass CA smog then it must have been running pretty well. Most of the suggestions here are for old sat-for-ten-years engines that barely run. Your problem looks like something broke recently. So don't go crazy, and make sure that you record every change you make so that you can undo it. You're on the verge of creating a terrible EFI nightmare.

I seem to remember that there was a short period of time when some of the links were NLA. Probably why all of these random sizes from random sources popped up everywhere. But now they all seem to be available from Nissan, for cheap. Why go elsewhere? They're even on sale at Courtesy. "Out of Stock" but it looks like that they still ship. Maybe they're not really available?

Just curious, this discussion could go on and on, but why didn't you just buy Nissan parts from Nissan? 4 x ~$7 = $28.

The leaking FPR, through the vacuum hose, and the coolant sensor are high probability and easy to check. The leaking FPR is one that would come on quickly too. The diaphragm cracks and it's broken. If there's gasoline in the vacuum hose it's toast. Those plugs look terrible, very rich. And you should use less never-seize. There's probably enough in the holes now to last the lifetime of the engine. It's dangerous too because you can over-torque your plugs. Not good in an aluminum head.

EuroDat, sorry for blowing up your thread.