NewZed

It was the LOL's... Why didn't you respond, if you understood?

I think that nobody offered advice...LOL... because nobody does what you're doing. Plus it doesn't make sense. You're not "building" a viscous LSD, you're using a housing that held a viscous LSD. You could have used an open diff housing and installed an OS Giken LSD in to it. Just saying...LOL... that you didn't get advice because you didn't really describe well what you were trying to do.

The problem is general. Some of the answers, and the overkill application of the pump. It's just bad system design. Here's a nice collection of data in one spot. https://www.highflowfuel.com/i-13775895-genuine-bosch-044-320lph-inline-fuel-pump-includes-an-fittings-of-choice-0580254044.html

People are making general comments that just aren't specific and not quite right. It's just confusing an already confused situation. The check valve is installed in the fitting at the outlet end of the pump. You'd have to disassemble the pump and intentionally remove the valve, for no apparent reason (just checked the internet and I see that people actually do that - for no apparent reason, apparently, except that they think it's "not needed". Maybe weight savings?...see last comment below...). The leak-down problem with aftermarket regulators is just the result of cheap engineering and low-cost manufacturing. The guys that make them will tell you it's a design function, to allow high-flow, but that's BS. When people get in to the putting these systems together they almost always go overboard on the simple irrelevant stuff and miss the basics. As you pointed out, his pump is way overkill for the rest of the system, and for the engine he's running. One of the basics of DC pumps is that they pull more amps as they work harder. So, with a flow restriction he's going to pull more amps and get low fuel pressure. The signs are there that his fuel system is out of balance, and over-spec'ed . He'd probably do well to get a lower flow pump, and fix his flow restrictions. Wouldn't be surprised if he has one of those tiny anodized fuel filters in-line, probably choking flow. No offense dpuma. But avoid the hype and the bling, and do the proper math is the way to get things working right. https://www.rceng.com/technical.aspx K&N filters. Cold air intake. Bosch 044. Turbo injectors. Electric fans............

All kinds of different things are getting mixed up and blended here. Retaining pressure when the pump's not running, maintaining pressure while driving, fuses to protect the wires (the device, the pump, is actually a current limiter and protects itself), low battery causing driving problems (what's the alternator doing while the engine is running?). You need to separate out and work on single problems. And get the cause and effect right. Here's a few things - the fuel system is designed to hold pressure for quite while (weeks or months have been seen in wrecking yard cars) after the pump shuts off. There's a back-flow valve in the pump, and the regulator is a pressure relief valve. Aftermarket regulators are almost all poor at holding pressure. If you have low pressure while driving it's probably an obstruction in the lines or a bad regulator. When the engine's running the alternator will supply enough voltage to run everything properly. It might overwork itself if the battery is dead but it will still put out current as long as RPM are up. The voltmeter reading will be a clue. Are you running two pumps on one circuit? The low pressure Carter pump counts too. There's a lot of backyard advice in the thread. Be careful and check multiple information sources.

The FS5W71B does not really use a "bell housing'. It's a combined bell housing and front gear case. If your FS5C71B uses a separate bell housing like the FS5C71A then it won't work. I could only find a picture of the A model, not the B model, in the 1972 FSM. The W and the C designate the type of synchro system I believe, so if the B designates the case style you might be able to use it. But. That FS5C71B might be worth more to a restorer. You could probably trade it for a worn out transmission that will work better. There are small issues with the early cases, like the reverse switch location (mentioned in that ZHome writeup, I think), that can be avoided with a later model case. The A transmissions are three piece, and the B's are two piece. Steel plates separate the aluminum pieces.

Did the links get broken during the move to the new software? They're jot Photobucket, they should be on the Hybridz server, I think.

Remove the gunk. Everything in that area should be steel. You don't want any gunk between mating surfaces of the wheel and/or adapters. Verify that it doesn't fit. Call zcardepot and get them to send you the right part. Why accept the wrong part from a zcar "specialist"?

Looks like you figured it out. 75 is the oddball.

Tire sidewalls, shock absorbers, and bushings are where the rough ride really come from. You mentioned tire series, but not much else about what you're running.

Nissan themselves eliminated one of the two sleeves when they redesigned the 5 speed for the 280ZX model. Leaving one on the propeller shaft but none on the the transmission. You'll just have opposite. The 280Z system is kind of redundant. If you ever get a ZX transmission you might want to fab one up. It would be easier to attach to the transmission in that case though. If the transmission cover extends over the base of the slip yoke you're probably fine. It will be like the ZX system in reverse. If there's a gap, things might get dirty. You might check fit before you get carried away. Edit - actually, by the picture, it looks like you'll have a gap. I'd extend the transmission dust sleeve slightly, easier. You could just run it though, and keep an eye on the seal. It's just going to get dirtier than if it had full coverage.

Nissan started staking the joints in to the shaft in 1975, directing owners to replace the whole shaft if there were problems. There are places that will modify the shafts so that the u-joint can be replaced. That's what he's looking for.

Worn wheel bearings, bushings, or steering gear are all likely on these old cars. Sounds like you haven't really checked anything out. Getting way ahead of buying another car.

When people say they did "all" of the tests, it usually comes out later that they skipped a few or didn't actually measure numbers, just continuity. Just saying, you have to be rigorous and detailed when you work on these systems. Good accurate numbers measured at the right times. For example, 35 psi on a running engine is too high, if you set the pressure while the engine is running. Besides that, if you don't show the numbers you got then people out here can't really offer good advice. Everybody says that they did everything right, so there's no wrong to fix. Also, 4.8 ohms is too high for injector resistance, so it makes you wonder where you got your specs. Although it alone wouldn't cause your problem. 8 psi is really low fuel pressure though. A fairly common problem is a blown FPR diaphragm. Of course, you'd have to have two bad ones since you tried two and got the same results. Just trying to help. Need more details. Are there numbers on the injectors, for example? That would be a clue.

Did you talk to more than one person? Can't imagine that the guy who designed it hadn't seen the press-in studs. Sounds like you didn't get far enough up the chain. Aren't the CV joints the weak link on many of the 930 style axles? The diameter isn't worth much if the CV joint fails. Torque and horsepower aren't the same thing. And multiple posts from the past have laughed at the 800 or 1000 HP claims. Nonsense numbers.

Have you tested the sensors that tell the ECU how much fuel to add?

He did a great job as a moderator here. He seemed like a really good guy. Looks like he was active on the site just recently, so it must have been sudden.

Some is normal. The retaining circlip has some play in both grooves. People have been known to lose the circlip or just not be aware that there's supposed to be one in there, and run with a loose axle. Take the nuts off and see if the axle is retained. You're sill misguided on your lug nut issue. Any play in the lug nut or stud area is bad. Any. There's no close enough. The wheel should be firmly attached to the flange, as if they were one piece. That's a basic of any wheeled vehicle, no fuzzy area to think about.

No problem. And I'm not your bud.

The loose lug nut thing is a big concern. How can you drive around with loose lug nuts and not know it? They were so loose you could feel the play be shaking the wheel by hand? That's a lot of loose. And there shouldn't be an "as much as I could" in there. There's either a torque value or you know from experience. Are you running steel wheels or mag wheels? There are many ways to have a bad wheel. Bent steel, or wallowed out aluminum on the mag, or lug nuts that are too long and bottoming out on. If you've identified a wheel problem, swapping to known good wheels for a test would save you a lot of time. You should spend more time on the wheels and make sure that they're right. I used a vise to press my bushings out, and only heated the metal behind the rubber to destroy the bond. Burning the whole thing is neat-o but really just makes a lot of unnecessary mess.

The easiest, closest thing to a bolt-in, option might be one of these - https://whiteheadperformance.com/performance-parts/datsun-240z-260z-280z-1970-78/240z-280z-diff-differential-axles-lsd/ They are hard to find on the open market, the CL's and eBay's don't have many. You can also get an open R200 and convert it to LSD with one of these - https://www.whiteheadperformance.com/?s=differential&post_type=product Neither of these are bolt-in because you'll need a different mustache bar, and modified propeller (aka drive) shaft. If you try to run all of that torque through an open R180 diff you'll probably just break it right away or it will wear out from spinning one wheel.

Here you can see that there's only 1.58" of travel combined in the two joints. Could be that your problem isn't too little travel, but too much, on the inner joint. 2 x "not much at all" = correct.

Your question has already been addressed then, you just need to use the answer in your response. Seems like you might be looking at your axle backwards. And 2 inches of travel in either direction would be 4 inches of total travel. I don't think that's possible.

You haven't really defined a problem, besides "very little", which, somewhat ironically, means very little. Also ironic, you need to be more articulate in your description. Seriously. It's not clear what the problem is.

You say unbalanced but you describe loose. Sounds more like a bad bearing or bad suspension bushings.