Zed Head

It should still start and run even with a dead cylinder.

Taking off from a dead stop. The higher the number, the easier it is. Less clutch work. If you use a ZX 3.062 with a Z 3.54, the 10.83 ratio (just multiply the numbers) is noticeably "doggy". Slow acceleration. On the other hand, some people put a 3.9 diff in their Z's to give them more zip. 3.321 x 3.9 = 12.95. Think of about 12 as what the Nissan engineers chose for the average driver. So about 11 is tolerable at the stop signs and lights, and about 13 is what you want if you're a light to light racer type.

The drawings are just representations. The hoses are smooth, the defrost tube does not shoot straight up, the front vents look different.

Nissan seemed to shoot for about 12 overall in first gear. You live in Texas so might do some 80 - 90 mph cruising, and not so many hill starts to worry about. Really depends on how you plan to use the car. These are coupe numbers. Things get weird in the 2+2 cars. Early cars 3.592 x 3.364 = 12.08 280Z's 3.321 x 3.54 = 11.76 280ZX's 3.062 x 3.9 = 11.94

It's probably just a 75-76 thing. You're hoarding the wrong cars. My 76 only had it on one side. Maybe they phased it out. 2, 1, 0.

Checking plugs and exhaust is the best way to see a rich condition. Here's another thing I learned years ago. The cylinders can lose their seal if they have surface rust and have dried out over the years. You can squirt a big shot of motor oil in through each spark plug hole so that it runs down around the rings to give you a temporary seal. A friend and I spent a day and half trying to get a 63 Bonneville started until an old farmer on a tractor came by and said "squirt some oil in the cylinders". It fired right up after we did that. It was a carbed engine but the same might apply here. Use one of those flexible nozzles or a piece of hose to get the oil up to the top of the cylinder so it runs down around the rings. If I were in your situation, I'd pull the plugs, recheck gap, squirt some oil in and let the gasoline dry out for a little while. Then squirt some starting fluid in each hole, put the plugs back in and give it a crank.

Edit - it's in the AC chapter of the FSM.

My 76 had something similar on the driver's side. It just blew air down on my feet. Can't remember if it said pull-push or not. The hose looks factory Nissan on yours.

Don't overlook weak spark. 1975 was the second year of electronic ignition. Not the strong spark of later years, just electronified points level spark. Make sure your plugs are gapped for it, around 0.029" I think.

The other "extra fuel" thing is the cold start valve. Somebody just had that problem. Your resistance looks about right, chart below. You can disconnect the fuel hose and plug it for a test. It will have full fuel pressure behind it so be careful. Something for the back of your mind - the ECU's often go super rich before they fail completely. Too bad, no quick fixes for you. Looks like you're on the marathon route.

What resistance number did you get from Pin 13? That's the coolant(water) temperature sensor. High resistance makes the ECU think you're in the Arctic. Adds lots of extra fuel. Pretty common to have a problem there. You could disable the fuel pump and see if it dries out enough to start with fluid. It will give you a clue about timing.

That's nasty looking. The thing with the damper and key and keyway is that they look so simple and crude but they are really very precisely machined and fitted pieces. You can see how the edge of the damper would catch on those dings and push it right out of the keyway. Now you know. Good luck.

The name is Silver...SilverFinger. Somebody likes silver. Check out the rocker/valve/cam cover. It's different. Arizona. @cgsheen1 ? https://bringatrailer.com/listing/1973-datsun-240z-153/

Green 72 with minor goobers. Lots of originality. https://bringatrailer.com/listing/1972-datsun-240z-171/

Silver 77 sold for a sensible price. $23,250. https://bringatrailer.com/listing/1977-datsun-280z-52/

Noun - person, place or thing. Thank you Mrs. Partridge, high school English teacher. She thought I was an attentive student but I was really just making a list of all of the parts I needed for my car.

nouns

Hence, your quandary. The "ping". Wonder if the slinger will fit inside the seal opening. You could still install one. Edit - never mind, your seal is out. Easy to do.

You can still get them. Doesn't seem to be much to them. Wonder which way the oil is meant to be thrown. Seems like the translation from Japanese should have been deflector, not thrower or slinger. I'll bet it is just a shield to keep the distributor gear from piling oil up in to the front of the cavity. Edit - actually the distributor drive gear is probably the "thrower". It sits right there throwing oil toward the seal as it spins. https://www.ebay.com/itm/313204496693?chn=ps&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&itemid=313204496693&targetid=1068323850870&device=c&mktype=pla&googleloc=9033513&poi=&campaignid=10459841973&mkgroupid=104612009900&rlsatarget=pla-1068323850870&abcId=2146002&merchantid=6520324&gclid=Cj0KCQjwl9GCBhDvARIsAFunhsk-dWNN7wM3i3pAAR4Cr-9JOEmxBrISOUjfedPQLrRQVC0BdKcf-fwaAlDGEALw_wcB

It's called an "oil thrower".

Reality bites for the 2+2 crowd. Only got to $9,500. Not enough. https://bringatrailer.com/listing/1977-datsun-280z-22-8/?utm_source=dm&utm_medium=email&utm_campaign=2021-03-19

Put some denticles on it. https://www.researchgate.net/publication/323011115_Shark_skin-inspired_designs_that_improve_aerodynamic_performance

I wonder if the oil slinger is the "metal plate" that somebody was seeing in a recent thread about the woodruff key. He was just trying to replace the seal and ended up with quite a mess. His key was jammed in the keyway at an angle. I've read that some engines didn't come with the slinger and many people just leave it out after working on the engine. Here's the thread -

Somebody on a different forum measured under hood temperatures for Z's and found that when the car was moving the air under the hood equilibrated to outside air temperature. It got replaced faster than it could be heated. Non-moving might be a different story, can't remember what he found there. His conclusion was that relocating inlets was not worth the effort.

Use the term "heat soak". It's been discussed in depth in the past. Aluminum fuel rails seem to help, they dissipate the heat, apparently. It's a very common problem.