Zed Head

carpartsmanual says they are. EuroDat's list probably also. Edit - I screwed up here and missed a "4". Sorry about that. They are not the same. http://www.carpartsmanual.com/datsun/Z-1969-1978/power-train/transmission-gears/4-speed/from-sep-71/25 http://www.carpartsmanual.com/datsun/Z-1969-1978/power-train/transmission-gears/5-speed/41

How did the focus shift from a battery drain through the starter solenoid wire (apparently a short circuit through the solenoid windings to ground) to the fusible links? I don't see a connection.

You could reuse the nut if you didn't destroy it when removing it. Just peen over a different spot or use red Loctite. You said that you have the early 5 speed, so a 4 speed should have most of the parts that you need to combine with what you have to make one good 5 speed, as suggested earlier. People have 4 speeds sitting in their garage as spares after a 5 speed swap.

People strap cameras under their cars and have good results in seeing what's happening. And if you posted a video of the noise somebody might recognize it. It's weird how the ear and brain can work together. "Banging noise" covers a lot of spectrum.

You never really know what you're getting at the typical pump. Today's cars are designed to adjust to the variation. https://www.fueleconomy.gov/feg/factors.shtml "Some fuels contain less energy than others. Using oxygenated fuels or reformulated gasoline (RFG), for example, can cause a small decrease (1%–3%) in fuel economy. Most of the gasoline now sold has a small amount of ethanol in it—up to 10% by volume depending upon the region. Using gasoline with 10% ethanol decreases fuel economy by 3%–4%. The energy content of gasoline varies seasonally. Typical summer conventional gasoline contains about 1.7% more energy than typical winter conventional gasoline."

Here's a new to market low number 1970 car. A bit crusty. Oklahoma. https://bringatrailer.com/listing/1970-datsun-240z-81/

The 78 sold for about what it did the first time. https://bringatrailer.com/listing/1978-datsun-280z-117-2/

Did you remove the snap ring?

The first one looks like a heat shield. Engine bay, exhaust area most likely. Looks like it has nuts attached so it would match clear holes. The round cutout probably fits around something round.

https://www.merriam-webster.com/dictionary/hydroscope#:~:text=Definition of hydroscope,steel tube — compare water glass

The wiring diagram shows a seat belt timer for the Manual and a seat belt relay for the Automatic. Possibilities. If you can find a really quiet place you might hear something click as you connect and disconnect the solenoid wire.

If you look at the list of things done before he calls it "rebuilt" you can see that it's not even up to the level of a remanufactured alternator. He just cleans and polishes the parts, skims the head, and puts it back together with new seals, apparently. The guy has been doing the same thing for many years. He even has newer complaints on the various review sites. I saw a few for late 2021. But, he's got a good web page and knows how to promote. Doesn't care about reputation, apparently, just making the sale. From his N42 head web page, below. The only new part is the valve seals. The heads only have a 30 day warranty. So, anyone who buys one better work fast. "REBUILD PROCESS INCLUDES: Complete disassembly, Inspection and Pressure test Deck Re-Surfaced Reconditioned Polished Rocker Arms Cleaned and Installed OEM stock Springs, Retainers and Lash Pads Full Set of new Valve Seals Stock Polished Camshaft. (Performance Cam Kits available, discount offered. call for details) All threads cleaned and repaired as needed Full Reassembly and Valve Adjustment (Re-Adjustment Required Prior to start up) 30-day warranty Trust your Datsun to a professional licensed Datsun Restoration business with over 15 years experience."

Tetraethyl lead's original purpose was as an anti-knock additive. The protective properties on the valve seats were an unexpected benefit, I think. It has an interesting history. The petroleum industry realized early on that the lead emissions were poisonous but pushed it in to the market anyway. $$$ https://www.britannica.com/science/tetraethyl-lead

Anyway, leaded gasoline and ethanol containing gasoline are two different things. Different issues.

You're also confusing ethanol with lead. Two different things. The good old days of leaded gasoline, and the corn lobby. Here's a pretty good summary of what's going on that covers many of the elements. The AP is, according to previous discussions, a middle of the road news outlet. One of the most objective. It's about the corn. https://apnews.com/article/biden-business-iowa-campaigns-elections-227e09a39aed1680e1f4813334aeae64 Members of Congress from both parties also had urged Biden to grant the E15 waiver. “Homegrown Iowa biofuels provide a quick and clean solution for lowering prices at the pump, and bolstering production would help us become energy independent once again,″ said Iowa Republican Sen. Chuck Grassley. He was among nine Republican and seven Democratic senators from Midwestern states who sent Biden a letter last month urging him to allow year-round E15 sales.

This looks like political commentary. If you want to talk about fuel, that's cool, but 10% ethanol has been around over many administrations, red and blue. The guy before didn't roll back the ethanol mandate. Biden has nothing to do it with it, really. The supposed reason for ethanol is to create a measure of independence from petroleum suppliers. A source of non-petro energy. There is debate about that. But it's not a red-blue debate.

If you're having cooling problems, a fan shroud is a good place to start.

Looks like the picture is as it was de-boxed. If you look at the coolant passages it looks pretty corroded. Also interesting that if "polished" means the rocker arm pads, that that is different than reground. I wonder how the wipe pattern looks.

Looks that way. It's described in the listing. The guy had actually bid and paid for a different car in the past, a Porsche for $50,500. Who knows, he might have got COVID-19. "This is a re-list after the vehicle was previously sold on BaT in March 2022 and the winning bidder failed to follow through with their commitment to purchase. This was not due to any fault with the vehicle. The winner has been banned from future participation on BaT and their buyer’s fee was not refunded." https://bringatrailer.com/member/rlife/

Just kind of funny. Nice looking car though. "rebuilt cylinder head with polished rocker arms sourced from California Datsun Inc." And blue combustion chambers. https://bringatrailer.com/listing/1978-datsun-280z-117-2/

Here's the "Trignition" ignition module page. (Trignition didn't really catch on, did it?). The last part change was July of 1976. Implies that 77-78 were the same part. But it doesn't seem that way in reality. Could help somebody looking at part interchanges if they don't want to switch to GM HEI or Pertronix. http://www.carpartsmanual.com/datsun/Z-1969-1978/electrical/engine-electrical-fitting/10

I learned something interesting in another thread about Nissan's move to electronic ignition systems, and thought it might be interesting to collect some stuff here. Nissan went from points to electronic ignition in 1974 with the 260Z. The coil still used a ballast resistor to limit current at long dwell times (low RPM). Spark gap was still specified at the gap used for points. 1975 and 1976 used the same basic system, an electronic module, a ballast resistor, and a coil, with spark plug gap set to the smaller points system gap. 1977 used the same basic system but opened the gap up to about .040" instead of the old ~.035". 1978 got rid of the ballast resistor and also kept the wide plug gap. Just collecting some thoughts while they're still in my head. I searched around the internet and found quite a bit of confusion about the ballast and 280Z's. Many people don't even realize that they have them, and assume that only points systems have a ballast resistor. Here is the carpartsmanual page for the ballast. The list doesn't quite match the picture, kind of confusing, the drawing says "to 74". So, does the 1977 ignition module pass more current than the earlier modules? Is that the difference that allows a wider gap? Interesting also that the first ignition boxes were aluminum with fins, to dissipate heat. http://www.carpartsmanual.com/datsun/Z-1969-1978/electrical/engine-electrical-fitting/3

The 5 speed is basically the 4 speed with an extra gear engineered on. The parts should be interchangeable. You can tell by finding the part number on the carpartsmanual site and comparing diagrams. @Terrapin Z has a large collection of parts. You might want to disassemble further though to see what all you need. Looks like the 4 speed uses the same part. http://www.carpartsmanual.com/datsun/Z-1969-1978/power-train/transmission-gears/5-speed/44 http://www.carpartsmanual.com/datsun/Z-1969-1978/power-train/transmission-gears/4-speed/from-sep-71/27

It will be interesting to see what he comes up with. I think he likes the later ECM's with NISTUNE. @cgsheen1 Anyway, it's been an interesting discussion. I learned something about the 77's. Good luck.