Zed Head

Most of the auto parts stores have the right pump if you just give them the year and model. Delphi seems like a good brand name. I had an Airtex E8312 and it worked well, and lasted about 40,000 miles. https://www.oreillyauto.com/detail/c/delphi-automotive/fuel-delivery/fuel-pumps---tanks/fuel-pump/fuel-pump/83db8e3f0135/delphi-automotive-fuel-pump/dlp0/fd0035/v/a/6634/automotive-car-1975-nissan-280z?q=fuel+pump&pos=1 Looks like Rockauto will save you a lot of money on the Delphi pump. Amazon has them also. They all look about the same, a silver cylinder with some hose nipples and a piece of rubber sheet for vibration damping. You'll need to use some ingenuity to get it mounted to where you won't feel it running. https://www.rockauto.com/en/catalog/nissan,1975,280z,2.8l+l6,1209204,fuel+&+air,fuel+pump,6256

Extend the rod.

Here it is. About 6 cm from the flat part of the fork to the edge of the bolt head.

Uh oh. Take that measurement that EuroDat shows. It will tell you if the throwout bearing is close. I have posted an measurement from the bolt head also. Not sure if it's in that thread or not. Yours seems a bit far away. Could be a short TOB sleeve.

Here's a Fidanza thread and a 92 mm thread, with some good clutch fork measurements from EuroDat.

More? What brand of flywheel? The Fidanza sticks sometimes. p.s. did you measure the stack height of the flywheel and throwout bearing? 92 mm. A very common error, mismatching the parts.

The P79 head had a bigger combustion chamber. The flat tops kept the CR up. 8.8 versus 8.3. People say the HP numbers are higher because the numbers were calculated differently. They are not actual measurements.

CO's comment about the reservoir is the most important one to focus on at this point. Apparently, you've been running with a low coolant level for quite a while. That's not good. Get the system back to the way it is designed to be and see what happens. If you lose coolant, there's a leak, as the FSM says. If you determine that you have a leak there are ways to find it. You can also verify a leak by pressurizing the coolant system. And, don't overlook that the coolant system is designed to use a certain type of radiator cap. The cap releases pressure but also holds vacuum. So that the coolant can pass between the radiator and the reservoir as it is designed to do. As far as looking for bubbles, the chemical test was developed and is widespread because the bubble method is not reliable.

Might be in here somewhere. Find it and check the part numbers and year ranges. http://www.carpartsmanual.com/datsun/Z-1969-1978/body-260z-280z/2-seater/front-fender-hood http://www.carpartsmanual.com/datsun/Z-1969-1978

The inhibitor switch provides the current that actuates the starter/seat belt relay. It's shown in your diagram. Two devices, plus the switch and the ignition relay, that have to function properly before power makes it to the solenoid. It seems unnecessarily complex, but it is what it is. SteveJ has replied but I must hit Submit Reply anyway

It's not an "overflow" bottle. It's a reservoir.

Seems like you might be avoiding the hard truth. Flushing the passages of a cooling system that used to work fine instead of verifying that your head gaskets are in good shape. If you have a blown head gasket flushing will not help. You can get a test kit for not a lot of money. Harbor Freight, OReilly, Amazon. https://www.lislecorp.com/specialty-tools/combustion-leak-detector Is your heater core connected? You don't have it bypassed? Bypassing the heater core can cause cooling problems.

That rim looks a bit used. Aluminum wheels can bend also even though they often break. I'd lift each wheel, set up a runout indicator next to it and give it a spin. A runout indicator can be just a screwdriver sitting on a cinder block. The guy that balanced them should have noticed something but might have had old equipment.

To be rigorous you'd try another 0.6 coil. Also, it looks like you're saying the 1.0 worked fine. Not clear why you went to 1.5.

Check your spark plugs. Use a borescope. How can you tell it's coolant smoke? I had a leak at the back of the head. Not obvious. Passenger side.

Z car wheels are lug centric. In other words, the lugs and lug nuts are used to set the center of wheel's spinning motion. I would check the holes in the wheels and the lug nuts. Make sure that they fit tightly. Those wheels require a certain type of lug nut, that fits the hole precisely, not the tapered seat nuts that a steel wheel would use. Also, check the seating surface of the wheel on the hub. Might be some crud causing wheel runout.

Couldn't tell, I looked back but I don't think you mentioned which coil you were using. Maybe in your other thread. I had a vague memory of a similar thread (among many, tach problems are common) and found it. Post #29 is the one.

The CA Datsun thing is probably for using a ZX distributor in a 240Z. The 280ZX's use a resistor inline to the tach also, just like the 280Z's. The 1978 ignition system is very similar to the ZX system. Nissan just shrunk the electronics down. 1978 and 1982 both use a 0.84 - 1.02 coil primary circuit specification. Both ignition modules are designed for the lower resistance primary circuit, and the tachometer system is also. You could just copy the specs from the ZX system. 1982

I'll go ahead and step aside here. Get a meter or test light and leave the key at Start. Start probing. Good luck.

That is not an ignition module. It's an ignition switch. https://www.carparts.com/details/Nissan/280Z/Beck_Arnley/Ignition_Switch/1977/201-1174.html Find it, unplug it, test the proper wires for voltage with the key at Start.

Somebody picked up a fun project today. Drivable with a spare engine and transmission. https://bringatrailer.com/listing/1974-datsun-260z-22-12/

Leave it plugged in use a screwdriver to turn it.

You have interchanged the words "ignition relay" and "ignition module" again. Relay and module are two separate things. Even so, cranking and running involve separate parts. If you don't have coil power at On then the engine should not have stayed running in your other test. So that doesn't really fit with what you described earlier. One possibility that might fit your problem is that the mechanical part of the ignition switch is not correct. I had a situation where I had to twist the rod between the mechanical part and the electrical part to get the electrical switch to turn far enough. That might explain why when you changed the switch it worked for a short while. The rod that fits in to the plastic slot has to turn the switch to the correct position. You can test it by disassembling the switch and turning it by screwdriver. You might find that everything works fine -

Just for fun and because the wrong words were used early on. Here are the three parts with "ignition" in their name - ignition switch, ignition relay, and ignition module. From ZCD - Autopartone - From Vintage z parts -