Zed Head

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👀 first.

You could have a bent hub flange or axle. It happens. Setting up a crude runout measuring device would tell you. Jack up a wheel, place a block some kind next to, put a stick on top and place the end close to the tire and/or the rim. Spin the tire and watch the gap between the stick and the wheel. Do the sides and the tread.

You're using precise numbers on initial timing, 10 and 15, but no numbers on the rest of the curve. And your test doesn't tell you about anything parts sticking. Sticky throttle plates are common. A new path to follow...

I don't know anything about your car's history. I'm just pretty pretty pretty sure that Nissan did not use fuzzy fabric on the visor. I could be wrong. You can probably feel the screw under the fabric if you squeeze in the right spot. Cut a tiny hole and stick a screwdriver in. Looks like somebody just sewed new fabric over the old vinyl. Probably made it heavier, so more droop-prone.

Really depends on what your goal is. I'd still take the breaker plate off and have a look inside just to be sure you know what you're working with. I collected quite a few and most of them had a stuck breaker plate (no vacuum advance), and crusty gummed up centrifugal advances. Might be why your idle speed is changing.

Intake vacuum is a diagnostic tool, not a target. You should know your distributor's vacuum and mechanical advance curves to help decide where to set your initial timing.

Nissan didn't use fuzz. You know where it is...

I am not implying that you should buy a reman computer but I just wandered across this on the internet. Apparently somebody is producing remanufactured ECU's. In "reman world" that could mean anything from all parts that degrade over time have been replaced to all parts have been tested and left in place if they worked. If you bought an ECU from ZSpecialties it was almost certainly a used one. Oliver has a huge collection of used Z's and Z parts, apparently. Anyway here is that link, just for future reference. Do lots of testing first. https://www.autozone.com/engine-management/engine-control-computer/p/bse-engine-control-computer-ecc1450/53480_0_0

When you check the wires at the ECU you're checking exactly what the ECU sees. If it's not right then you move down the wires to find the source of the wrong numbers.

Sitting in the driver's seat the plastic panel would be directly left of your left knee. It has a rectangular hole in it that allows you to see the tag on the ECU. There are two or three screws holding it, one of them does not need to be removed all of the way. Borrowed this from the BAT 8000 mile Z.

Did these pros run through the tests in the EFI Book by Nissan? Easy to do and you might find something. Might be you just have a bad connection at the coolant temperature sensor. You can sit on the ground and reach in to get to the connector. Hardest part is getting the kick panel plastic off. You didn't answer the question about the age of the replacement ECU. If the failures are due to age of parts then all of the parts are the same age so have the same odds of failing. p.s. I've found that piece of solid core copper wire, flattened, works well to get in to the connector pins. They're tight.

No, I never did the rear disc swap. I hadn't heard much about Milkfab until now. Looks like they have some interesting products. https://milkfab-engineering.com/shop/ols/products/datsun-240z-260z-280z-rear-big-brake-kit https://milkfab-engineering.com/shop/ols/products/2005-2014mustangbrakecaliper Hope they/he make(s) it. Many don't, running a small Z car focused fabrication business seems to be tough. https://milkfab-engineering.com/about-us

The rotors are interesting because they can be off center and still work just fine. The pads will not know., they'll just create a new circle. There could be a very slight weight imbalance.

I looked but did not see anything. Tried all of the words - seal, gasket, filler, oil... Got nothing. Edit - I tried again, working my way through their new website sub-menus and finally got to the secret link. Wrongness and unavailable. Gaskets and seals > Oil cap > o-ring https://www.thezstore.com/category/552/gaskets-amp-seals https://www.thezstore.com/category/789/oil-cap

You probably meant ZCD. MSA has nothing. Who knows what "new" means. The cheap one looks like a hardware store flat gasket. https://zcardepot.com/products/oil-cap-gasket-seal-oem-240z-260z-280z-280zx?_pos=8&_sid=583fc178d&_ss=r https://zcardepot.com/products/oil-cap-gasket-seal-240z-260z-280z-280zx?_pos=5&_sid=583fc178d&_ss=r A person could probably find something that would work on the old internet. https://www.mcmaster.com/products/gaskets/

I have a truck with hub centric wheels that uses flat faced nuts to hold the wheels on. Torque spec is 150 ft-lbs. It's an interesting topic. One of the first of my many cars had a set of mag wheels with replaceable adapters for different patterns that fit in a recess in the wheel surface. Very sketchy. Most of my cars back then had numerous vibration problems so I never noticed if the wheels were one of them. Found a picture of a similar wheel. https://inthegaragemedia.com/rolling-stock/ Here's a Ford hub centric lug nut. The hub centers and helps out but the nut and lugs do most of the work. This is aftermarket, the Ford nuts have a spinning seat with some grip texture on the face. Still flat.

Nissan didn't mention the hydraulic pivot until the 1983 FSM. It only has one nut.

So it's basically a counterfeit part sold out in the open on eBay. Nissan packaging. I see that the guy put some stuff in the description. Still looks like a cover-up for somebody to buy counterfeit Nissan parts for resale. No need to spend time on the packaging if you're telling the world it's a reproduction. Item description from the seller I needed a gasket for my original oil fill cap for my Datsun 620. The original part number 15270-78500 is now discontinued, so I looked at a picture and took some measurements, then made my own. Maybe someone else needs one too! My part number here is 15270-78501 to denote a variation of the original part. I've used this on my truck for a couple weeks so far with no issues. Made from Overture brand TPU. This should work for any vehicle calling for the original part number with the original cap. I tried to select all vehicles based on what NissanPartsDeal says these are supposed to fit. If using the elephant logo cap, the ridge goes into the cap, but the Nissan lettering cap, the ridge should go towards the valve cover. Feel free to contact me with any issues, suggestions, or requests!

I don't think so. If the wheel is properly designed for a lug centric application it should have the same likelihood of misbalance as a hub centric wheel. I think that the problems come out when people use a hub-centric wheel on a lug-centric hub or vice-versa. Which looks like what you're thinking about doing. If Rota designed the wheel as a lug-centric wheel then they most likely would have balanced/centered it around the lugs. The hub hole would be low tolerance. Plus, the lug holes will be tight tolerance and if your adapter is not centered between the lugs you could find a tolerance mismatch. You might even end up putting a bending load on the lugs when you force the lug nuts in to the holes or down on their tapered seats. And, you'll need to match the center of the wheel to the center of the hub in your adapter/spacer since it's not just a gap filler. It is a spacer that has to fit two centers. Neither the hub or the wheel was designed to be the centering mechanism. It's more complex than it seems if you want the actual mass to be centered and supported. Apparently, hub centric can be stronger than lug centric. But, it still comes back to the engineering group that designed the system. Here's a simple review. The guy covers some of what you're considering. Things to be aware of. https://www.machinedesign.com/fastening-joining/article/21832042/whats-the-difference-between-lugcentric-and-hubcentric-wheels

Looks like you answered your own question. Center is center, not clear why one method would be better than another, besides perception. Since Nissan did not use the hub as a surface meant to fit another surface then there would be no reason to have a tight tolerance on the machining process. So you might find that each of your adapter/spacers will have to be custom-fit. Don't forget the longer lugs or longer lug nuts. Don't know what type of nut the Konig's use, tapered seat or shanked. 15mm is substantial. Or maybe it's 25mm. Nissan either made a typo or can't do math. Probably supposed tobe 0.59.

What do you mean by "uniform size"? Here's Milkfab. https://milkfab-engineering.com/

siteunseen's head was rebuild by Dover Cylinder Head. People often converted the hydraulic pivots to solid using Timesert parts. From everything that I've learned, in the USA market, the P90(a) only came on the turbo engines. The US market has many differences from the rest of the world market. Here's an old thread about the Timesert conversion.

You should start a Youtube channel. Paint store head porting in Alabama. I'd watch it.

Have you checked the cam that's in it? Probably factory turbo cam but who knows.