NewZed

Get it running and drive it. Probably not worth restoring. They are easy to work on. Service manuals are available to download on several different Z sites.

It will be interesting to see how things hold up. Are you using MIG welding? I assume that you are but you didn't say. There should be warping at each weld spot which might affect bearing wear since the inside of each cap is essentially a bearing race. Besides loss of heat treatment. Not trying to be negative, just assessing the odds. Good luck.

@Dat73z If you wanted some discussion about your recent post you'll have to post in a non-FAQ section. People can post new stuff in FAQ but nobody can reply. It's been this way for years, not clear why nobody fixes it or at least adds a note to new posters. You didn't say which u-joints were "too soft". That would be helpful.

Don't overlook the shield.

Might have better luck on classiczcars.com. More traffic and there are some parts traders there. Good luck.

Bumping zboi's thread so he can continue his contributions to the community. Let's see an update.

The internet is a great place to learn. Learn first, then speak. https://www.investopedia.com/terms/e/economiesofscale.asp Where are those dyno numbers? If the engine still runs.

I don't have Megasquirt but I know a little bit about EFI. Don't the MS data tables show injector open time? Duration? If open time isn't at 100% then it's not the injectors, it's MS not commanding them to stay open longer to provide more fuel. If they are at 100% then increasing fuel pressure should increase their flow rates. Sometimes on problems like yours it helps to break things down to the smallest elements. Analyze each step. What should happen versus what did happen.

RTPD = Read the post disappointed You should have created a fake name that at least leads to the mystery company. https://www.google.com/search?q=Flex+Engineered&rlz=1C1SQJL_enUS862US862&sourceid=chrome&ie=UTF-8

This part of the Megamanual might help. https://www.megamanual.com/begintuning.htm#spark https://www.megamanual.com/ms2/tune.htm

You have to look at your MAP tables. At high vacuum (low pressure) you can run more advance for a cleaner burn and better efficiency and better throttle response. At higher RPM under open throttle most people have found that about 34 degrees is where you get the most power. You can read a bunch in the L6 FAQ sub-forum about having timing set "all-in" at about 2500 RPM or various numbers around that. Meaning that it stops advancing and just hold at that advance number from there to the high limit. If I was starting with an MS tune I might first just mimic a stock engine's timing curves. Nissan provides them in the Engine Electrical chapters. You have to do some translation. And the charts are in distributor speed so that's where you have to do the doubling. From back in the days when they had distributor tuning machines. The early FSMs have an actual graph. Later ones have just a table and let you imagine the lines. Here is 72 and 78. 78 would be like your engine probably if it's a stock 290Z engine. They have different options for different markets and different transmissions. Generally, lower advance is for emissions states, like CA. Reduced timing is cleaner. notice that they give the starting point, zero degrees at XX RPM. So the first entry shows vacuum advance starting at 200 mm Hg, and increasing to 15 engine RPM at 350 mmHg. Centrifugal starts at at 1200 RPM and rises to 17 degress at 2500 RPM. It's like a mini general physics course. It can be confusing, especially since centrifugal is tied to crankshaft rotation but vacuum is just tied to air pressure in the manifold. Sometimes I still wonder if I'm thinking about it right. It's easier to grasp if you have a stock distributor on a running engine with a timing light to learn on. Good luck. 1978 EE chapter. 1972 EE chapter.

Not sure exactly where you're going or what the current problem is, but I think that the first comment above is incorrect, and the second one is correct. Also, you were talking about cam timing and ignition timing together at one point (the 4 degrees thing). They are completely separate as far as spark goes. You could move cam timng all over the place by switching holes on the sprocket and it would not affect when the spark occurs, relative to crankshaft position. Timing sensors are all measuring where the crankshaft is in its rotation. Cam timing is also relative to crankshaft position but adjusted separately from ignition timing. Just some hopefully helpful commentary.

I see what you mean about the pucks. Looks like a 240Z? Later ones were scalloped. If there's a gap and they're hard you can get a clunk when the diff and mustache bar twist under acceleration or deceleration. Or just from riding over bumpy roads. I haven't seen separate aftermarket parts, kind of surprising. Seems easy to reproduce. Here's some part numbers if you want to look around for NOS. Any year will work, the difference is the shape. 30 and 31 - https://www.carpartsmanual.com/datsun/Z-1969-1978/axle/rear-suspension The shifting clunk usually comes from the diff nose rising up then dropping back down, because of a loose front mount. The basic problem, that Nissan also was trying to solve, is that if things are too tight you get diff noise/whine transmitted in to the body. If they're too loose you get thumping and clunking. It's a balancing procedure. Probably best to ease your way to where you want to be.

The mustache bar bushings look okay. A new front diff mount will probably tighten things up a lot, worth doing. People have been very happy with the stock mount, if you can find it. The PU bushings were made for racing applications and pseudo-performance mods. I'd just do the front mount and see how things work. Not really sure what you mean by the "puck things". By the way, you can remove the mustache bar bushings by just heating the metal around the rubber while pulling or pressing on the bushing. The bond will loosen and they'll slide right put. The smokey bonfire approach is dramatic but unnecessary.

You're probably the first. I'd look at the short nose R200 and R230 mounting systems for ideas. It's hard to find a way to support the short nose diffs. Here are some threads. You can't get a reply if you post in them, becuase they are in the FAQ section, so make sure to post in this thread if you have questions. https://forums.hybridz.org/forum/83-drivetrain/