Zed Head

I've wondered the same myself. Maybe a translation thing? OD has to be 5th because it's OD right? Maybe top is the highest before you get to OD? The followup question might be "what would you do in 4th that you wouldn't do in 5th?" Interesting (to me anyway) thought question, aside - why is overdrive significant? It's really just one factor in a string of multipliers. At the end of the full calculation, it's essentially meaningless what that single ratio is. But it sure does look like somersetting in the advertisements. I think it's one of those buzzy words that just sounds impactful. Example - "Bachman-Turner Overdrive". Much more exciting sounding than the Bachman-Turner band. But close to ultimate meaninglessness. They don't even play that fast.

People sometimes have to grind them off.

A mirror, long socket extensions, a wobbly socket attachment, and tape could all come in handy. Working on them is an acquired technique and can be very frustrating in the beginning. Make sure that all of your surfaces are clean and flat when you reassemble because the exhaust system is prone to leaking. Even new headers sometimes need some minor surface work. If you think that stud is about to break, stop and think hard before deciding to go ahead and snap it off. Heat, and PB Blaster and tricks might be better used early than late. The same problem is there with the thermostat housing bolts. They like to break too.

The FSM doesn't really cover that very well. Here's a better picture from a parts manual site. There are clamps below that hold both manifolds at the same time. You might get just the intake off alone, but most people remove both at the same time. 78 used studs and nuts with "yokes" that clamp the manifolds. They look like thick curved washers. http://www.carpartsmanual.com/datsun/Z-1969-1978/engine-280z/manifold-egr/from-aug-76

Yes, just ran a hose straight to the distributor. Make sure that it's the correct hose, from the bottom of the throttle body. Ported vacuum. You can determine your transmission, or you can look for the switch. Find the wires sticking out from the passenger side of the transmission. One will certainly be the reverse light switch. If there are more, disconnect the wires (if they're connected) and use a meter to determine when the switch is closed (continuity) and when it's open. If you have a checker that beeps you can just connect it then climb up and put the lever in to fifth and listen. You might that there's only one switch and the decision is easy.

Here's a good reference, in addition - http://www.gates.com/oreilly/PDFs/Fuel Systems.pdf

It actually only opens the vacuum line to the vacuum advance mechanism on the distributor. It's an emissions thing, page EC-9. I think that, generally, the view is that retarded timing gives cleaner exhaust. They must let it actuate for highway cruising because it gives better mileage. Which also gives cleaner exhaust. I removed mine and just let the vacuum advance work in all gears. I think it adds a little throttle response since the timing is generally more advanced at mid-range RPM. If your 5 speed doesn't have the top gear switch, it's useless anyway. There are a whole range of switches on the various 5 speeds so it's impossible to guess what you might have. The 83 ZX has the most, I think, you could check that FSM.

The guys that really know diffs say that wear of the spider gear shafts and their holes is commonly from one-wheel burnouts. It causes the diff to spin abnormally fast, and thus the spider gears, and wears the shaft bearing surfaces. In some cases you can see the wear around the shaft as the hole takes on an oblong shape. It can get really bad. This allows the shaft to **** (male chicken) and the spider gears to get misaligned. It sounds like what's happened to yours. If that's the case it can't be rebuilt anyway. If the fluid is changed and they're driven normally they really do seem to last almost forever. I'd examine what you have more closely to see if you can find what's worn, then examine any used ones to see if they're better. On the other hand, the STI diff is pretty nice.

You could probably just get another Nissan R180 from somebody who did an R200 swap, if you wanted to get back to basics quickly. Diff removals and installs are pretty easy so the issue of putting a worn diff back in doesn't really matter much, does it? Really? You just want the Subaru LSD diff. Right? Rebuilding an old R180 doesn't seem effective at this point in time. Some day they'll be hard to find there's probably a decent one out there somewhere that is better than a rebuilt one will be. They're pretty durable.

Bazaam!!

Wrongness. Don't do this stuff. OBX, MFactory, 87-89 300ZX. Whitehead Performance. Those are your fundamental search words.

The topic isn't really location dependent, is it? Wires is wires. Amps is amps. And after that it's really "don't run over 20 amps through a device that can only handle 20 amps". And 1N5402 is a diode, not a relay. Not to wizz on your post, new views are appreciated. The big gauge wires are generally used for the starter draw. As noted in a recent post., the starter motor draws a lot of current. Beyond that, a dead battery would probably be the biggest draw. Jumping dead batteries causes many problems. My radio in my other car reminds me often.

That's a good point about the Start versus Run power at the ballast. It will do a similar thing if the AFM contact switch is dirty or non-functional, but will run for a few seconds on residual fuel pressure. SeK, you should try the starting fluid. It will tell you a lot. And if it does start then die immediately, you need to say that. Won't "turn on anymore" could mean too many things. The answer is in the details. There is no "CPU icon" on a 76. Where is this thing located?

The damper has little effect on fuel supply. The system will get just as much fuel with it as without it. And the ethanol doesn't have much effect either. I've been running 10% ethanol for about 7 years and 50,000 miles. Sounds more like an ignition problem. Check for spark. If you have spark, try starting fluid. If it starts with fluid but dies quickly then you'll know you have a fuel supply problem. Could be lack of injection.

I've never heard of this problem. Usually they're just corroded from sitting inactive. Never read of such a detailed flaw in the design. Where did you get your info?

That's an odd solution to the problem since the TPS (more correctly called a TVS) only changes state right off idle if adjusted correctly and again at full throttle. Shouldn't be in the picture at all at 1600-1800 RPM. Red herring? Or maybe it's misadjusted.

Just seemed odd. Picture attached.

I would just find the original 1978 S and L wires and make it work with those. All alternators after about the mid-70's are the same at a basic level. The more modern ones have added features, like extra sensing wires for the ECU, but the S and the L are common. Find those two and you can make the SI work. The L wire does not also connect to voltage sensing, on the Z diagram. Edit - the L wire is the most important, because it runs through the Lamp in the voltmeter. It will tell you when the alt is failing. Worst case, find it from behind the dash and tap in to it.

That's not a bad idea, actually. The guts pull right out and you're left with a brass well/adapter for whatever you want to put in there. The ZCD part doesn't have temperature specs. It might just be the switch for the injector cooling fan, which is set at way high temperature. I spent some time looking for a switch that was set lower and found that BMW had several. Plus you might look at whatever the Ford Taurus uses since that's the popular E-fan setup. Get on the Google, find the temperature you're looking to start at, and make it work in the adapter the PO made for you. Edit - don't some fan controllers use a sensor, and a programmable, or settable, system? Might be better than just an on-off switch. Tunable.

Here are the two panels shown in the 76 FSM. They put one in Body Electrical and the other in Air Conditioner. Edit - oddly, the AC unit has an extra fan speed.

I wonder how much one of these companies would charge to wind up a custom set. A person could ball park a shorter spring and add some pounds to rate of the stock springs. Or look around to find Tokico specs. and ask for those. Might be worth a quote. Some have a catalog to browse. http://www.coilsprings.com/ https://www.springworks.com/custom-coil-springs/ http://mwspring.com/custom-springs.html https://www.eatondetroitspring.com/coil-springs/ https://www.centuryspring.com/

Eibach seems a lot like Vogtland. They don't actually have a product for the Z cars, but somebody has found some of their products that work. Maybe they get them mixed up at times. There's no sign of any Datsun products on their web sites - http://eibach.com/america/en/ https://eibach.com/de/en

The sensor might actually be a switch.

Probably BSPT. Pull out what's in there and measure it or take it to a decent fittings store. http://www.ralstoninst.com/news/story/the-difference-between-npt-bspp-and-bspt-seals

I've seen that "cooling fan" circuit before but never seen an actual fan. There are a few things in the 280Z diagrams that don't seem to exist, but they persist in the diagrams. Have you actually found the plug at the end of the wire? I've never seen it. According to the diagram that circuit starts at the fusebox and also runs the defogger. It's a 20 amp fuse. Most of the Z car plumbing is BSPT. It's stock, to Nissan, but it's not common. The stock factory fan and fan clutch work really well. No big benefit to an E-fan.