Captain Obvious

Wow. That's simply no fun at all! Glad you're OK!

Oh, and forgot... About the bearing seating surfaces. What are the shiny spots at the 10:00 position (and other spots)? Are they dents IN or bumps OUT? I'm assuming they are dents inward, but figured I would check:

Yes, you have to wiggle the calipers around a little and look for the minimum dimension. This is because you are looking for the shortest distance between two points and unless you have the calipers perfectly square to the faces which you are measuring, you will be seeing the hypotenuse of a triangle instead of the shorter side. Problem is, in an application like this, down in a hole trying to register on small surfaces, it's difficult. If you have larger flat surfaces and better access, you could use the wider, flat part of the jaws to make the measurement (like you are doing on the distance piece). But down in that hole on those small surfaces, you are unfortunately limited to using the narrow ground tips portion of the jaws. So you have to "finagle it". And yes, the more pressure you apply, the lower the reading. And that phenomenon becomes more pronounced the longer the piece you are checking because you are actually bending springy things a little and the farther apart the jaws, the easier it is to bend the beam between the two of them. So you have to "just get a feel for it". But on the good side, look at it this way. You have already reduced your hub measurements by at least twelve thousandths. Only a couple more to go! Try doing things like this... First, the bore where the bearing sits does not have a perfectly square corner at the outside. There is a little rounded fillet down there at the bottom of the holes. Make sure you stay away from that as it will increase your measurement. Second, wiggle the caliper around while applying a small amount of pressure until you get the absolute minimum you can find. Let the jaws slip around a little on the hub until you get the smallest distance. That should help position the jaws directly opposite eachother and reduce the hypotenuse effect. Third, move your thumb off the dial, and use the little wheel below the dial to hold the caliper in place, And try to apply the same amount of force every time you take a measurement. See where my thumb is when I'm taking that internal measurement: I'm completely confident in the external measurement you are making on the distance piece. Try to use the "same amount" of force when making the internal measurement on the hub faces? All of this stuff is where "the knack" comes into play. From what I see above, my opinion is that last couple thousandths is "the knack" and you have the correct parts. Zed, Where on the casting is that mark? I've never looked for that mark. Is it in some rusty, crusty spot that is probably undecipherable at this time?

I'm still holding out 95% hope that it was a measurement error. Make sure the bores where the bearings go is clean and there are no burrs kicked up anywhere. I use an eye loupe for magnification of all the surfaces involved.

Oh... Here it is: https://www.classiczcars.com/forums/topic/60007-78-280-re-assembly/ Maybe the "M" spacers are .020 longer than "B"?

Crap... I knew it was just a matter of time before someone asked that question. I don't really have a good answer. I just can't explain how that could possibly be the case, and therefore I don't really have a good solution, other than to make special custom distance pieces to accommodate the situation. Or get "normal" strut bodies that aren't screwy. I haven't looked closely at the sizes involved, but it is also conceivable that one could place appropriately thick hardened washers "in series" with the distance piece to bring it's overall effective length up to what it needs to be to work in a hub that is .020 too wide. McMaster carries some very thin hardened washers. Haha! But I simply refuse to seriously entertain anything like that until someone can prove to me that you have a hub that far out of spec. PS - There was another guy looking for replacement distance pieces because he needed "B" and what he had in his possession was "M". I've never heard of "M" and was curious about what was going on there. I didn't look into it at the time, and now I can't even find the thread... I thought it was on this forum?

Oh, and I forgot... @Patcon The custom hub-fitting caliper is on it's way. You should see it soon. Weds or Thurs.

That's about the only thing I could come up with as well. Since that bronze is softer than the steel, it will ooze out a little if the torque is high enough. Although, I'm not sure the normal expected torque is anywhere near "high enough". Nissan said it was to reduce noise. We talked about it a bunch in this thread: https://www.classiczcars.com/forums/topic/58935-lost-rear-bearing-shim-washers/ They put it in at the beginning of 72 and took it back out the middle of 73: I still think the whole thing was a fire under some engineers butt and that was his knee-jerk bandaid. As long as the marketing guys were convinced, then it was a success.

Looks like it was a great time, and cool that CZCC was well represented. See the way Zup sits there with flat tops at his feet? Like minions.

Nice. Is that the NNJ club? Or the Long Island maybe?

Your memory is fine. It was added to try to quiet something down back there. But the thing is... I don't understand how it could possible do anything like that. The geometry just doesn't make sense. It's like they got a couple complaints back at the factory and they lit a fire under some engineers butt who quickly threw a half-baked poorly thought out fix at it. Then after a couple years, they took that same fix back out. Probably because they realized it cost money and didn't do anything.

That bronze washer has nothing to do with the bearing preload. It's outside the races. You could get the exact same effect by adding metal to the inside face of the yoke and making it that much longer. Doesn't fall into the geometry at all. Doesn't matter. Honestly I'm not even sure what Datsun was trying to do by putting it in there at all. Doesn't make much sense to me. So, here's to hoping it was simply a measurement area. I'll get those calipers out to you tomorrow and you should have them Wednesday or Thurs. I just can't believe your hubs would be out of spec like that.

But before you go applying force to things, I just have to ask... Do you have the room in the upwards direction for that thing to even move off the rack splines? Reason I ask is if that is the only bolt you have removed, it won't come off the rack because it has nowhere to go (up). So... Did you take the bolt out of the upper end to make sure that intermediate shaft COULD move at all? Is the upper end frozen in place?

Sweet. I love it when a plan comes together! Keep your old one in your glove box just in case? I know it doesn't always work right, but it might get you home some night if the new one go wonky in a different direction?

Ooop... I got mail...

I found one round top needle valve. I have no idea if it's factory or aftermarket, but it is the old style with the hardened steel seat and the regulating spring built into it. It measures .079 through hole, so it's at least what the book says is correct. I'm pretty sure I've got a couple others around here somewhere, but I don't know when they will turn up. I will keep an eye open for them though and let you know if something turns up.

I got this pair of cheapie plastic H4 headlights as part of a larger parts purchase, but I cannot use them because of my state inspections. I might be able to sneak something through that looks more like stock, but these would attract too much attention. $25 for the pair? Plus actual shipping. Local pickup is fine too, as well as delivery to Zcon in Atlanta in the fall.

I took a quick look at the wiring diagram, and I do not believe the fuel warning lamp is activated during the bulb check. @Dave WM do you concur? Also, Here's a fresh copy of the most interesting of the pics from above:

Yeah, I can't imagine what stage of electrical disrepair I would be at currently if it weren't for Wayne's wiring diagram. There are honestly projects that I would have simply not tackled if I had to spend that same time tracing the wires on the stock multiple page monochrome diagram.

Oh, and forgot... Since the last time this topic was active: I filed the offset tab off the AIRTEX / WELLS5S1523 (SU4115) sensor and installed it. It works great.

I'm sure replacing those connectors didn't kill your ECU. Probably something simple like you mixed up the thermotime connector and the WTS connector somehow. If you do that, it'll run pig rich, burn you eyes, and foul your plugs in short order.

I will start digging around here to see what I have. Of course, I have no idea if what I have is factory or aftermarket. And I've also got a number of float valves from flat tops... I wonder if they are the same. I never looked into that. I would be really surprised to find out that the difference going from a L24 to an L28 is enough of a change to push you over an edge like that though. I guess I've seen stranger things, but it would just be surprising. Makes me still wonder if there's something wrong with the delivery system somewhere upstream of the needle valves. Finding needle valves with a larger through hole might fix the symptom, but still might not be reversing the root problem, just accommodating it. Although, if that's the case... does it really matter? Fixed is fixed? :)

The fantastic 77 color wiring diagram was created by Wayne @wal280z. Here's the latest. It's Revision "M". It includes the two changes mentioned above (voltage regulator and illumination light in the Temp/Oil gauge): 1977 Color Wiring Diagram Version M.pdf And if you want to see any of the history of changes, here's a thread with some details: https://www.classiczcars.com/forums/topic/11727-color-wiring-diagram-for-280z/?page=3

I'm not sure there is a "standard" size for the needle valve hole. I wouldn't be surprised if different manufacturers might have different sized holes there. What's the hole size in yours? I've got a couple around here that I can compare when I get the chance. Are your valves original, or aftermarket? And as for the vapor line potentially causing the problem, I doubt it, but it certainly wouldn't hurt to check. I was going to suggest a run with the gas cap off or loose, but I really don't see it. And even if there is a problem with the venting, it's not caused by the vapor line. The gas cap itself is supposed to have a check valve built into it such that it allows air into the tank to replace the volume of fuel removed. If that valve in the gas cap is blocked and doesn't work, you could draw a vacuum on the tank and make it hard to pull fuel out. Although, I'm not sure you would see that stark of a difference between WOT and just cruising around normally. Nor would I expect it to be that fast acting or repeatable.

Absolutely not. The bearings have nowhere near .020 free play. If your measurements are correct and the distance between the bearing seating surfaces is .020 longer than the distance piece, then it won't work. The bearing will certainly bind when you tighten the nut to even a modest (50 ft-lb). Your balls will be pushed together so tight, you'll feel like... Well, like your balls are in a vice. I'm hoping it's just a measurement error. So what do you mean by "scallop"? Can you take a pic of how you're making your measurements? Want me to send you my newly made custom hub-checking calipers? They have been calibrated to a NIST traceable standard and everything. You can use them to make a direct measurement and then give them back to me at Zcon? Be happy to. And the amount of torque really doesn't matter. In theory, all of the pieces down the center have been crushed together taking up all available play. Once all the play has been taken up, there is very little axial movement even as the torque increases. I'm no bearing expert, but IMHO, there should be no discernible difference in bearing preload between say 50 ft-lb and 200 ft-lb. We torqued Matthews bearings to maybe 50 ft-lb at my shop and he was going to do the final torque at home. He bought a torque wrench that goes high enough. On my own car? I tightened them with a 1/2 inch breaker bar and some black iron plumbing pipe until my eyes bugged out just a little. I don't condone or suggest that level of cavalier behavior, but... I didn't measure it, but it was "a lot".