NewZed

It's a spacer for the flex plate. You need to remove it anyway to mount your flywheel. Pretty sure it just pries off easily. Then the seal will be exposed.

Vacuum leaks tend to be most significant at low air flow. At high RPM there's so much air going where it's supposed to go that the small leaks become insignificant. You could have the injectors tested pretty easily. Here's a shot of some flow test results from injectors I had on my 76 that actually ran pretty well. I tested them myself at full flow rate. It ran a lot better when I got a matched set on it. If you're handy you can figure out how to short the injectors at the ECU and let them squirt. Pop the rail with injectors and give it a try. Beware the gas fumes and sparks.

If the spring was bad or stuck the coil spark would have been jumping the gap all of this time. That would cause more heat and ozone and wear on the electrodes. My mistake on the ballast resistor. Later cars have an extra terminal to bypass the resistor for hotter spark. Apparently 1972 does not. Since the engine's not blowing up your best option might be to just buy two of a higher quality cap and keep the extra in the car as a spare. Good luck.

How long ago is "used to". Could be a mouse nest in the air filter box. And you only confirmed that #6 was involved but didn't do the same for #5. You might have one dead cylinder instead of the two that you though. 82 would have a catalytic converter also. Make sure the exhaust system is free-flowing.

The XR700 is just an electronic version of points. That's why you still need the ballast resistor. The PS40 has 1.4 ohms primary circuit resistance which is very close to the 1.5 to 1.7 ohm range of the stock coil. Lower primary circuit resistance is how they "up" the performance, so yours is on the barely improved end of the performance range. The coil should only be running hot if the new ballast resistor is lower resistance than the stock one. Or if you wired it backward and have the resistance bypassed. None of those should cause your distributor cap to self-destruct though. Looks like you just got a low quality or defective distributor cap. The current that passes through the cap is very short time frame and very high voltage. They're designed to take huge voltage. Your problem looks mechanical. Good work though on the troubleshooting. A new high quality cap should get you right back on the road. Everything else looks pretty good.

Burleigh was making them a few years ago. @BURLEIGH

I have some plain old Tokico non-adjustables that I could sell you. I only have three though, one got damaged. I've been looking for a fourth for a long time but it's not going to happen. A pair might keep you going. I think the damping rate is similar to the middle setting on your Illuminas. I'm in Washington County, by Portland.

As far as the diff, propeller shaft, and half shafts go it's all just like a 280Z, except for the diff mount. The length of the propeller shaft (the main drive shaft) is different but the diff and half shafts will swap between S30 and S130. Your problem sounds more like u-joints. If you don't have a turbo car or a 2+2 you will have u-joint half shafts. So that's six u-joints total for your car. You can figure some things out under the car with a strong light and a prying tool. Pry the u-joints around and look for any movement, they're tough you won't break them. Grab the pinion shaft and yank on it. None of those things should have any play. Won't be surprising if you find some, with your symptoms. Get some sturdy jack stands so you don't end up in the news.

1982 R200's are just like all of the previous long-nose R200's. You'll need to move the ring gear over to the new MFactory carrier. So if your ring and pinion gears are damaged you'd probably be better off finding an R200 in better shape. Otherwise, if the ring and pinion gear are in good shape, and the pinion bearing, you'll be installing new carrier bearings anyway, and the diff will have new internal gears, so it should be a standard swap. So...what do you mean by "big crap"?

It might have been. The piston in the slave could have pushed forward allowing fluid to escape and air to get in. The rubber dust cap will hold it in, it's a tight seal. Easy way to tell is to pop the rubber dust cap off. You can do it by finger with everything assembled. If a bunch of fluid comes out that's a sign. Be careful, the dust seal can hold pressure and fluid will squirt. Also possible that you didn't get the throwout collar clipped/positioned to the fork correctly. Put it on the wrong side, maybe. No offense.

One last thought - the tick-tick-tick noise you heard early on could also be a broken pressure plate part rattling around. Or somebody might have dropped a nut or bolt in there. Lots of little crannies to get stuck in.

Seems like you're stuck in a "think loop". You need to do. Think-do-think-do... If you think it's the transmission, find another to bolt on there. 90% of people who have a Z have their old 4 speed sitting around somewhere. I do. You didn't sound so confident that the motor might not be the problem, in your first post. You put "I think" after your comment. Why would you take it back to the guys that might not know what they're doing? You're just going to watch them do the same thing that didn't work the first time. My car had a lot of heat through the shifter hole when I was missing the rubber seal. That was with everything working perfectly. Just a lot of hot air down there. If you want to get a little crazy, drill a hole in your transmission so you can see the input shaft. Maybe you'll see a misalignment as it spins. Or, here's a way to be sure that the input shaft is not turning - put the transmission in gear with the rear tires locked. Maybe on jack stands with the parking brake set. Hold the clutch in and do the rev test. The transmission input shaft can't turn so all you have is the pressure plate and flywheel spinning around the clutch disc. That takes all of the rotating part of the transmission out of the picture, but with everything hooked up. If you still get a vibration make note of any burning clutch smell, in case you're not getting full disengagement. Don't do it with tires on the ground, if your foot slips you might blow a hole in the back of your garage. Or just make sure it's pointed the right way. One last thing on the pressure plate. Maybe it has some broken parts inside, they do break. That might be why they had to get so crazy with their drilling and welding. The loose parts might be moving when you press the pedal, maybe the thing is unbalanced now. Of course, if that's the case, then it would make sense to go back to the balancing guys. Or just swap pressure plates. Just suggestions. Good luck. Thanks for the puzzle.

Are you sure that motor is designed to handle that amount of mass on the end of the driveshaft? Maybe it's the wrong type of motor.

I've seen many times where the assumption that the one thing that should be the problem can't be the problem because it's already been checked or fixed, often ends up being the wrong assumption. Everybody is suggesting, in essence, that you try another flywheel and pressure plate. It's the obvious next step. The Nissan flywheels and pressure pates are all externally balanced. Any parts you grab should be worth a try. Your balancing guys did a crazy amount of work on that pressure plate. Very abnormal.

It's just another part of the system to make sure is right. A bad bearing, broken "nose" piece on the transmission where the collar rides, cracked clutch fork, worn out pivot ball, clutch fork not seated properly on the pivot ball, etc. Anything that could be causing uneven force or imbalance on the pressure plate fingers.

His main point was the collar, AKA sleeve. The part with the two ears on it that the clutch fork sits on. It needs to match the pressure plate. It's possible to get a tall pressure plate and a tall collar and have the clutch partially disengaged at rest because the collar is pressed against the front of the transmission cover. It's a good point. Here's an old thread about how to go wrong. https://forums.hybridz.org/topic/43715-changing-the-slave-for-more-pedal-throw/

Thanks for that correction. After I posted it I realized it wasn't 100% correct in a universal sense. Only in a relative sense, objects in motion and all that. I almost edited it but decided to leave it, and went with "indirectly" instead. You described in more detail what I meant by "the car is the dyno". More relativity. Getting the variables right is the key to good results I think. On a static "dyno" the variables should all have been calibrated and measured. On the "virtual" dyno, the car dyno, it's up to the user to get them right. Small things like tire radius, weight, wind, road slope all play in to it, as you pointed out. For the "post your dyno results" these things might be more important. This thread is half brag, half share. Still a neat idea. Surprising that it hasn't been "app'ed" sooner.

Sounds like something heavy then. Flywheel or pressure plate. The transmission shafts don't have much inertia, near the center of the circle. With the clutch in the pressure plate is disengaged from the clutch disc, which itself has negligible mass, and transmission shaft. See if one of your friends has a flywheel, clutch disc, and plate setup in their garage. Maybe they'll let you borrow it just for a test. I have two myself but I'm in Oregon. Most of us don't have our parts balanced, they come just fine from the factory or the store. It's weird that your guys had to do so much.

Always a possibility that the shop that ground your flywheel and balanced your parts didn't get it quite right. Maybe the smoothness of the electric motor is exposing what are actually small imbalances. Good luck.

Just to add an illustration. The main drive gear, as they call it, is pretty short. The needle bearing is between the main shaft (9) and the drive gear (1).

If you engaged the clutch with the input shaft pushed off-center it will be orbiting around the true center. Probably pushed to one side. Is your pilot bushing set right? Seems like the input shaft was pressing on it.

I can. You had the input shaft bound up between its bearing and the end of the motor shaft. It's going to be cocked slightly, no way to rotate on-center. All transmission input shafts have some play in them. I had four in my garage at one time, they all have play. The bearing in the transmission is a ball bearing, balls in races. There's play, it's not a needle or a tapered roller bearing bearing. That's why the pilot bushing is so important. I think that you might have found your problem, the bind between transmission bearing and motor shaft. I wouldn't spend any extra money until you put it back together with things they way they're supposed to be.

Don't overlook either, the old backward clutch disc. Springs toward the bolts can cause rubbing on the bolt heads.

Okay, I watched the videos. They're actually very short and kind of cool. I wonder if your clutch disc is bent. Not uncommon, if you let the transmission hang on it by accident. That might cause some drag even with the pedal depressed and vibration. You could put it back together without the disc and give it a test.

With the clutch disengaging the transmission the pressure plate and flywheel spin around the clutch disc and transmission main shaft. If the transmission is in gear and the clutch pedal depressed it should be like the transmission is not even attached to the engine. When you engage the transmission the imbalance is probably magnified by the extra mass of the transmission input shaft. You must have done some machine work to make the end of the motor's drive shaft look like the end of a Datsun engine's crankshaft, for the pilot bushing and the to mount the flywheel. Seems like you might have something off there. The "coupler". Good luck.