Zed Head

What does it smell like?

That hose (from your labels on the picture) runs through the Air Regulator and just bypasses the throttle blade to keep the idle up until the Air Regulator valve closes. Have you checked the PCV valve and hoses underneath the intake manifold? That would cause a vacuum leak. The crankcase should be totally sealed to everything except intake manifold vacuum. You should find a diagram in the Emissions Section. Might not fix your main problem but could get your manifold vacuum back up.

The gauges on the old Zs aren't very accurate. Mine has a mechanical pressure gauge fitted to the same port as the sensor for the electric gauge in the dash and the dash gauge reads low by about 20 psi. I would first get a gauge that you know reads correctly and verify your oil pressure.

I have found the AC valves on-line but could never determine if the seals inside were fuel rated or not. And I still have a spare spot on my fuel system for a gauge (the old CSV spot), which would be convenient. The reason I started looking again was because I just did some fuel system work, swapping injectors, and realized what a pain it was to depressurize (note - even with a leaking FPR some pressure remains) and drain the fuel lines. Now I can (or will be able to once installed) just connect the pressure gauge, and use the pressure relief button on the gauge to dump the fuel. It's just a convenience.

The numbers are in the FSM, with service and test procedures. http://www.xenons30.com/reference.html

I think that the "evaporative system" contains the vent to the gas tank. You may have plugged that vent which might cause fuel pressure or flow problems. Just a thought.

I was in the salvage yard the other day and found an in-line Schrader valve on the fuel lines of an Isuzu Rodeo. I've looked around on the internet for something similar but could never find anything. The Schrader valve is common on today's fuel injected cars, as a port for a fuel pressure gauge connection, but the old Z cars don't come with them. All of the newer cars I looked at have them installed on the fuel rail so not easy to transplant. I haven't installed it yet but it fits 5/16" hose like the stock 280Z lines so should be easy to splice in. It will be convenient for fuel pressure checks or adjusting, and for relieving pressure if I need to remove any fuel system components. I've attached a picture of what I ended up with. On the Rodeo there is more hard line after the cut but also several fixtures and bends that I didn't want. If someone knows of a similar in-line valve on a different model car, I'd be interested to know of it. Putting this out there for those that might want to add something convenient to their car for no significant reason.

How long have you been waiting? Hours, days or weeks?

The drilled cams have small, but easily visible, holes on the base circle of each cam lobe to let the oil out. If your cam doesn't have the holes, then it's a spray-bar cam.

Apparently, the rotors are different, starting with the 260Z, which you apparently already know. But if you have 280Z rotors on your 240Z, you must also have the 280Z front struts and hub assembly, I believe. Maybe you should check those dimensions. That's all I know. Good luck.

They look like aftermarket rotors. What is the distance, compared between the two, from the bearing seat to the rotor face? And the dust seal seat. That will determine if the rotor is centered in the caliper, assuming the bearing diameters and other critical dimensions are the same.

How long are they? And how much space do they have to fill? The space to fill should be the same on all 280Zs with the same shocks. The shocks determine the fully extended length between the perches.The only other variable is spring length. If some people need a compressor and some don't it could be because they're using different shocks. Maybe aftermarket shocks are not all the same.

Here is a thread from the recent past, with a similar problem to yours - too much fuel. http://www.classiczcars.com/forums/showthread.php?42574-MPG-timing-fuel-and&highlight=mileage

This one? - http://www.classiczcars.com/forums/showthread.php?34192-280ZX-Distributor-Advance-Curve-Reference&highlight=Distributor

Can't help on the Eibach spring fit, mine are stock. But the dimensions you're working with would help, since the distance from spring perch to spring perch should be the same for any 280Z using the KYB 361002 in the front struts. I have the KYB 361002s on the front of my 280Z and could measure the distance from perch to perch with the front end off the ground, as could anyone, for comparison. With that measurement (maybe it's in the FSM?, I haven't looked), anyone with a new spring could measure its length and determine if they'll need a compressor or not before they even start. Do you know the length of the Eibach spring? Maybe they've been cut in the past.

You could put it in an oven at about 300 F. or hotter. The coefficient of thermal expansion is higher for aluminum than steel, that should open the gap. Let it soak to get full growth of the piston and gap. Oven mitts should be okay to handle it. Never done it myself, but that's what I would do. If you want to save the piston and sacrifice the rings, you could try taking a small center punch and break the rings out in pieces, on the hot piston. One more WAG - Naval Jelly might reduce the oxidation that's holding the ring in the groove. Oxidation, if that's what happened in your case, tends to "grow" the parts it's working on. Get rid of the oxidation, you might get rid of the sticking.

You have problems. 80 lbs is high. I think that the pressure relief valve in the block behind the oil filter is supposed to go at ~60 lbs. The spec. for oil pressure in the FSM is 50 - 57 psi at 2,000 RPM. If you unscrew the oil filler cap with the engine running does the engine run really bad or die? That would be one clue that your crankcase is sealed correctly, with no vacuum leaks. Since you're trying to run a functioning PCV system, that's what you want.

Page BE-42 has a pretty good clue (hint - already mentioned once) about the oil pressure and temperature gauges getting weird at the same time. Get a separate pressure gauge or thermometer and verify that what the dash gauge reads is true. Does your PCV system still function? If not, have you vented the crankcase? You need one or the other, blowby gases need a place to go. Most blowby blows by the rings. Blowby is the gas from combustion and it contains moisture. Those gases need to get out of the crankcase.

Have you checked the transverse link (LCA) bushings? Inside and outside, and the spindle pin and nuts? Maybe the transverse link, hub assembly and wheel are moving as a whole unit. Or the hub and wheel are rocking around on the end of the transverse link.

You might need to bleed the system a little better or adjust the pedal linkage to get more travel in the master cylinder. Were both cylinders changed or just the slave cylinder?

So what kind of help are you looking for? You're not answering the questions that will get you the help. The more details the better.

How far along are you? You didn't say which ignition system you'll be using. If you're using the 280Z ignition module and distributor then you'll need to either keep those wires or rewire. Or use a GM HEI module or MSD or similar if you're not keeping the Nissan ignition system. If you really are a total wiring noob, you should probably keep the stock ignition system if it's still in the car. What do you have? Which distributor and which ignition module? Don't tear too many wires out, at least one of them is needed to drive your tachometer even if you go with an aftermarket ignition system.

There are good diagrams in the FSMs if you want to compare the pinouts of the ECUs. EFEC section - http://www.xenons130.com/reference.html

You unplugged the water temperature sensor that the ECU reads, the one with the same connector as a fuel injector. The water temperature gauge sender (sender is just another word used, the FSM calls it a thermal transmitter) that connects to the temperature gauge only has one wire connected it. The FSM also says that if the temperature and oil pressure gauge act up at the same time, it might be the voltage regulator (the one internal to the oil pressure gauge). How is your oil pressure gauge doing?

The 280Z EFI system fires once per revolution according to the FSM. Edit - Deleted my short story, since it was barely relevant.