NewZed

Sounds like fun. If it hasn't been driven for a long time it might be a stuck valve, or ignition timing. If it's running might as well let it run and loosen up while you check the basics.

You're welcome on the name. I didn't say it wasn't possible. It's just not rational. To followup on rturbo, pick your base engine (looks like you want to go LS) and build up from there. The wrecking yards are sprinkled with cars that had drivers who didn't react faster than the oh shit feeling. Just seems like you're getting ahead of yourself, if you really want to drive what you're building. On the other hand, there are many "builds" happening out there that have never been driven and they've been going on for years.

I don't know exactly how they work but some 240Z's have an inhibitor switch. I think it's on automatic cars to stop the engine from starting while in gear. If you have an automatic make sure that it's in neutral. Also check for power at the starter solenoid wire when you turn the key to Start. Do that for sure before you replace any parts. I've had a loose solenoid wire that just wasn't making connection to the starter solenoid. Almost bought a new starter... The clicking is probably just the accessory relay turning off power to the accessories, for Starting.

You didn't say WHEN you get the clicking noise. I watched parts of the video but can't tell what's happening at the key when the click happens. Is the click when you turn it to Start, or Acc, or Run? I got vertigo before I could tell if you actually turned the key to Start, and had to stop.

"Rabbit hole" seems about right. A fantasy. Why have you chosen such a huge amount of power as your first project? And "on a budget". Apprentice welder. Seriously, what you've proposed is kind of ridiculous. Here's a thread to look through - http://forums.hybridz.org/topic/125328-ford-88-irs-swap-v20/?hl=%2Bford+%2Binch

The old edit without ID'ing what's edited... I always add an "edit" in front of my edits. Here's a good site for comparing parts, and sometime the Google will even find old stock for you - http://www.carpartsmanual.com/datsun/Z-1969-1978 If you get the Wolf Creek racing axles, it actually is kind of the inverse of an R200 swap. Except for the pinion shaft flange. http://www.wolfcreekracing.com/index.php?option=com_content&view=article&id=22&Itemid=31 Edit - the reason it's like an inverse R200 if you get the axles is because you can use your stock halfshafts. R180 mustache bar, Nissan pinion flange or modified propeller shaft, and the diff axles, and you're rolling.

That's a good link and answers a lot of questions. It's an interesting area, the Z car diff mounting is an odd thing.

It does clear things up, by quite a lot. He answered each question, specifically. But you have to put some of your own thought in to it. The first question about mustache bars kind of shows that you haven't even really started thinking yet, or that you don't trust your own thinking. You were on track with the comment about automatic R180's but apparently didn't trust your own thought process. There's a ton out there about R200 swaps. Read up.

Have you tried jumping the starter solenoid wire at the starter? Have a mechanic check your starter. When you turn the key to Start do the dash lights stay on or does everything turn off? Is the "sensor light" the exhaust gas sensor lamp? That's the only "sensor light" I see. Is it a Turbo car with ECCS, or NA with the EFI system? Two different systems. The NA car does not have a brain and the ECCS brain is abbynormal. Neither will shut down the engine, I believe. Too many possibilities, hence the need for more detail.

Need more detail.

That is right. So, basically, your wiring is not as the factory intended it. Get the factory wiring diagram and make it like it was. Try the Electrical chapter - http://www.nicoclub.com/FSM/280z/1981/

Just a refocusing type comment, but driveline balance and runout problems would be more tied to drivehsaft RPM, not load. The original comments about angle changing due to diff nose lifting seem most likely. Based on the stated facts. Something that changes when load is applied. Seems like this latest effort might be helpful but off target.

Don't forget that if the air in the engine bay is just recirculating through the radiator it won't do much cooling. A lowered car with a front air dam might not allow the hot air to leave. Your observation about what happens with the hood open is a clue. Maybe focus on getting the air out from under the car, or through the hood, or access panels. You might be just spinning your fan blades otherwise.

You need a diode on one of the wires from the T plug. You didn't say what year car you're working with. But it's a common problem, after people rewire their 240Z's to use an internally regulated alternator. Pretty sure that the L wire is the one that needs a diode. Position the diode so that current only flows to the alternator but not back. Found a good description. I think that all you need to do is add the diode. Post #4. Assuming that somebody else already rewired everything else for an internally regulated alternator. http://www.zcar.com/forum/10-70-83-tech-discussion-forum/110443-more-73-240z-voltage-regulator-swap.html

Where's the Google link? It is odd-looking, that's for sure. What kind of Z are you working on?

Don't mean to be a downer but if you still have a rubber diff mount in the back, after the PO installed 500 horses, there might be a lot more lacking back there. Kind of sounding like it might be a build budget depletion sale from the PO. Good luck and read some of the SUNNY Z and RebekahsZ threads, among many others, on breaking things and how they fixed them. You might still have the original open diff.

We used to call that dog-tracking. It's caused by the rear wheels being on an axis that is not parallel with the front wheels' axis, when all wheels are parallel to the car body. If you can see something odd about a rear wheel that's a good place to start, Could be worn bushings. How is the wear pattern on the rear wheels? Is this a right hand steering wheel car? Passenger side and right side are the same for US models. I found a few links on the old interweb. These cars don't have a lot of adjustment so you probably have a bent part or worn bushings. https://www.theglobeandmail.com/globe-drive/culture/commuting/dog-tracking-should-give-a-driver-pause/article1367167/

You have a thicker radiator, an AC condenser, and a shroud of some kind, with electric fans. Anything else up there? Cold air intakes, intercoolers (not clear what engine you're running), horns, alarm systems, spoilers..etc? Maybe you just have too much area blocked and a too long path for the air to flow. A simple test of coolant flow versus air flow might be to increase your idle speed and see if it overheats faster or slower. Since you don't have a mechanical fan all you'll be changing is coolant flow rate.

It might just be a different style of shaft, instead of a length of machined rod. Could be that the center piece locates and retains the shaft ends in the center of the diff. The sides of the piece also support the spider gear, and act as another bearing surface, probably reducing wear. It looks like just a more robust two pinion diff. Probably little benefit to swapping, unless the other diff is worn. Spend some time measuring wear on the other diff.

Nissan addressed a similar problem in 1974. They defined another phenomenon that they called percolation. Basically it's hot float bowls causing the fuel to evaporate, making the fuel-air mixture over-rich. They wrote a thing about it. http://www.classiczcars.com/files/file/60-fuel-system-modification-plus-73-74/

The RTz design can be modified if your angles are off. Holes can be slotted, the GM mount can be ground. You're right though, if it's good at cruise and decel now and you change the angle, you might create a new problem. The best way to go is to measure and make it right. Hoke probably considered angles when he designed his mount. You might send him a message and ask what diff angle he designed for. Apparently he monitors his Facebook page most closely so that's probably the quickest route.

Dang. I was just about to post a suggestion. It was a good one too, 5 years of thought behind it.

Just puzzle-working, but if it ran well when you shut it off in the evening then ran rough when you started it in the morning, doesn't that imply that the seat fell out over night, or just after you shut it down? The valve was open, the seat dropped, the valve started beating on it as soon as you restarted. And, just for consideration, it seems possible that the valve seat area cracked and let the seat loosen. I think I see the coolant to chamber crack in your picture, but have you checked the seat area for cracks. Just trying to get the story filled out.

Here's a good start - http://forums.hybridz.org/topic/58895-what-is-the-deal-with-solid-diff-mounts/ There are other descriptive threads out there, including one by Ron Tyler, explaining why he made the modified diff mount. His moniker here is RTz. Use Google and "site:hybridz.org" in the search box along with your search words to search the forum, the site's search function is very poor. It won't even use the three letters RTz so you can't search for Ron's post. And he's a moderator.

That would still be a two then. Don't know what that thing is. Spin the wheels and see what it does. Interesting puzzle. I've seen similar parts in images but haven't dug in to the various varieties out there.