Zed Head

That's a good find. The N42 page, the first that you showed in Post #4, shows the intake seat changing in 6/75 (fairly close to Nissan's Bulletin), and the exhaust at 4/76. So a 75 might have harder intake seats, but probably not exhaust. My 1/76 build would have the harder intakes, but soft exhaust. I put about 20,000 miles on that engine and didn't have any problems. I think I rechecked lash at 10,000 miles. Seemed like it had never been off, it's out of the car now.

My mental summary ends up at "hot carb boils or vaporizes fuel in bowls, boiling fuel leaves via jets, unmetered". The basic principle of the carb's float bowl is a placid calm pool of fuel pushed in a controlled fashion through precisely sized orifices. Bubbling, vaporizing, recondensing fuel screws everything up. But the basic idea of all of these things and Nissan's obvious work, and their modifications, and writing up a whole book about it, and attempts to explain the concepts is "heat is bad for the carbs, avoid heat". That's the message, I'd say. Remove and avoid heat transfer to the carbs. Heat is bad. Heat is the enemy. See a path for heat to get to the carbs - remove it. Is more testing necessary? Heat, heat, heat, heat... Just joking around. Seriously though - the key is to remove the things that transfer heat to the carbs.

As noted, the FPR's all regulate to the same pressure. The ports are different, but otherwise they're the same. Considering the work done, and the fact that three valves were out of their adjustment range, a check of the wipe patterns would be a good idea, wouldn't it? The FPR problem might be saving your engine. Don't run it until you give it a good inspection.

That's actually normal behavior. Nissan started putting both inches and mm on the X axis in the 1973 FSM's if you want to look at a few curves with those units.

Price cut in half. $3500 now - http://portland.craigslist.org/mlt/cto/5808738675.html

The image attached is how Nissan explained it, in their 73-74 Fuel system Modification Plus manual.

Seems like a normally closed switch that opens under vacuum would be the way to do it. Have you checked continuity across the pins? Looks also like it's just asking to be taken apart and examined. Looks snapped on.

Generally people seem to say that the harder seats didn't show up until the N47 head, I think. But Nissan does mention hardened seat materials in the 1976 Service Bulletin. Seems like if they reported it in 1976 then the engines before probably didn't have it. I'd say "unlikely". If the valves and seats wear your valve lash will close up. That could be a maintenance check to do, to head off problems. Edit - might as well post the words in. Pictures below.

You won't really know what needs replacing until you get in to it. If the cabin has been dry the ECU should be fine. The injector quality will depend on the fuel that's been sitting in them. If the fuel pump and FPR were in good condition when it was parked, the system could have stayed pressurized for years. The connectors on the wire end are simple to replace. Rossiz put a lot of effort in to getting his EFI right before he switched. He didn't switch to carbs because it was bad. He's your best bet for getting parts that are known to be good. If you can determine what you need maybe he'll break it apart for you to save shipping costs. I imagine he has the EFI intake manifold sitting in his garage with the rail, injectors, FPR, linkage, etc. all still assembled on it as it was when it was on the engine.

Everyone told you to do this. Did you do it yet?! Nothing will change until you change something!

I see. It seems like the real question is "how much antifreeze is too much?" for the track inspectors. I didn't see his second post. He just needs containers and space for storage. Carry on.

I only know because I picked up a spare complete ZX engine. You do know the later ZX's have the lambda sensor in the exhaust manifold? It's the narrow band type and the manifolds are shorter so the down pipes don't swap. I don't know if the threads and bosses are the same either. But if you realize that you're going to end up removing manifolds, it might be an option. I've been pondering using a 1990's Nissan EFI system on my car so have looked at some of these things also. Looks like lots of fun. Will you be running your three injector drives as a single batch fire or grouping them in to a sort-of semi-sequential system? I don't think I've seen a three x two system.

Are you confusing Water Wetter with the Evans system? You can mix Water Wetter with antifreeze. http://www.evanscoolant.com/how-it-works/conversion-installation/ https://www.redlineoil.com/content/files/tech/WaterWetter Tech Info.pdf

Are you using the 280ZX TB just because it's off the car and easy to work on, for installing the TPS? Or is there another reason? The 280ZX TB is actually smaller in diameter than the 280Z TB. Which is odd because, as many know, the ZX engine is rated at higher HP (calculation formula change and all of that). Anyway, the hose to the ZX TB is smaller than the one to the Z, in case you weren't aware. Might help make your AFM decision.

You can spend 300-$400 for a good carburetor. So if that's not included, add that in. It's pretty simple to convert though. The EFI harness is separate from the man harness so all you do is disconnect it at the battery. I think that you might need to work up some throttle linkage. Cable is common. The pump would just be a common low pressure carb pump, replacing the EFI pump. Make up a list for both systems to see where the dollars balance out.

Last comment - I read a few more web pages. If I were doing what you're dong I'd find out what all four of those pins do. Could be that you need both L and F to get things correct for the CS144. Edit - just saw somebody say the "F" stands for Failure indication to the ECU. Kind of fits the wiring image above. They're mostly all saying also that the the L circuit in the alternator is low resistance and the wire needs outside additional resistance, to avoid overheating/failure. So, add a resistor the L wire and you should be in business. Edit 2 - way down this page the guy, who seems to know some things, says the resistor is used in a parallel line. This actually makes more sense. People may just be warping and assuming things they read, in their head. http://www.pirate4x4.com/tech/billavista/Wiring/Part2/ I'd just measure resistance on the L to case circuit myself, and if it's above 50 ohms wire it up and run it.

Just for fun you could measure resistance from the L pin to the alternator case (ground). If there's 50 ohms or so, then the whole "need resistor" thing might be bogus. Madelectrical seems to be the only site saying it's needed. Sometimes things can get parrotted all over the internet if they're said with authority. An exclamation point has amazing power. !

I'll bet the diagrams they used for the Z are from passenger cars and trucks that don't have a fancy ammeter, but that did have a light. Looked again and it does look like the W to the regulator, which would be the original L (BW at the alternator) wire, comes directly from the fusible link. So it's a direct 12 volts, no resistance. If the GM guys say you need a resistor you probably better install one.

Looks like L comes through the ammeter shunt. Probably some resistance there. Where's the electrical guys? I'll step away......... Edit - I think the above is wrong. The 260Z diagram is hard to trace, all black and white.

And the link that Steve showed is for 280Z's. Better be careful.

I forgot about that. It's funny though, the wiring diagram shows a bulb in the circuit, before the regulator. Excerpt below from 1973. One of the pre-voltmeter people would know more.

Here's that reference. It's not very good, since it's really referencing voltage drop. Actually it doesn't make much sense. It's for the CS130, which is what Steve linked you to. If that application worked, yours probably will be fine. http://www.hotrodlane.cc/ONLINETECH/CS130DREG.html

The bulb in the L wire on your car is a resistor. I have read though that the CS alternators don't like too much current on the L wire. I'll see if I can dig up the reference. I searched "cs144 pin out" and looked at images.

The wiring diagram shows an EGR relay wire that's BW, in that area. Does the wire have power with the key On? And the 1976 wiring diagram shows a condenser attached to the Ballast, like yours is now. Could be that's not even an ignition system wire.

"Spitronic"? Is "spit" the way "injection" translates from Dutch? @ ing superlen... @superlen He might be out there. Once you're free of OEM EFI box you'll be looking for more power. Cams, head work, yada yada...