Zed Head

WOW! Too bad you weren't looking at the hole when you were doing the "hear it ticking" part. You could see it ticking. 0:23. Edit - watched some more and see that you were. Oh well. Check your oil for gas. It's probably at 0 viscosity.

No offense but you seem to be going round and round with "sag" and rake. If you explained what you were trying to do and what you've changed so far you might get better advice. These cars are old and in many cases the springs themselves have "sagged" from when they left the factory. So one person might get rake and another might get sag after replacing parts. The MSA "spacer" is just a way for people to replace their old 280Z insulators with new 240Z insulators. But even the rubber in the insulators has parts that sag. There is actually a small rubber piece inside the insulator that's called a spacer, that compresses over time, causing "sag".. So, another point of confusion. http://www.carpartsmanual.com/datsun/Z-1969-1978/axle/rear-suspension/13

Are you sure it's not an L26? The LXX would be stamped on the block. And where are you going to find an extra 2.2 mm of stroke? Seems like a lot even for a reground crankshaft. Not an engine expert...

It will be about 0.7" less than it should be. MSA/Zstore designed the spacer to give 280Z owners an option to get their proper ride height with a new insulator. Sorry for the ranting. I've been watching World Cup soccer. We got van Gaal'ed. p.s. I don't know what the wheel gaps are on a 280Z so can't really say what they'll be with four 240Z insulators. But they will be 0.7" lower in the back than a factory stock 280Z. According to MSA.

I'll bet a person could just make a solid "donut" of metal or plastic and extend the short insulator studs to make a much cheaper adapter. The donut takes the compressive forces and the standoff nuts and studs take the tensile. Should work. https://www.mcmaster.com/standoff-nuts/ https://www.mcmaster.com/studs/

I reread your post and the Zstore page and see how they have confused things. It looks like what they were trying to say is that their new spacer plus a short insulator is "almost" a match for the original 280Z tall insulator. Kind of poor writing. "will raise"..."compared to the front insulator alone". They should have just called it a "short insulator adapter". "These adapters, when fitted to the factory front strut mount insulator and installed in the rear of a 9/74-78 Z-Car, will raise the rear by about 18mm (about 0.7") compared to the front insulator alone, effectively replacing the original taller rear insulator (or restoring height for those who installed a shorter option previously)"

It's at $85,000 now. With 20 hours still to go.

Well, there's bumper height and then there's body level. I guess rake might be measured by wheel arch gap? Don't know. It's a visual thing. As far as the Zstore product, it actually lowers the rear end by 0.05", by their own math. Unless "nearly" means 0.05". 3/4" = 0.75". (They really shouldn't be mixing measurements like that. Pick one and stick with it.) Or maybe "about" means 0.05". Who knows. Nearly, about, 0.05", 3/4 inch, 18mm. 18mm = 0.071". https://www.thezstore.com/product/5532/rear-strut-mounting-insulator-adapter-kit-9-74-78-260z-280z "Description: Nissan discontinued Rear Strut Mount Insulators for 9/74-78 260Z & 280Z many years ago. The Front insulators were the same height from 70-78, and are still available, but they are nearly 3/4" shorter than the factory late 260Z & 280Z rear insulator. ... These adapters, when fitted to the factory front strut mount insulator and installed in the rear of a 9/74-78 Z-Car, will raise the rear by about 18mm (about 0.7") compared to the front insulator alone,.. "

I think that my comments about the bumpers didn't really address the "why" of the struts. The rear 280Z struts are longer after the redesign of the body. It might be that the 280Z's have more rear suspension travel than the 240Z's. Seems like they could have used the same insulators and matched the strut length to it. Probably an engineer "perfecting" something, or just starting from scratch.

The spacer that the ztore is selling is designed so that they can sell insulators for both small bumper cars and big bumper cars. What they're saying is if you want a replacement insulator for your big bumper car you have to buy the short 240Z insulator plus the spacer. Because the "correct" insulator is NLA. They should really call it an adapter. It adapts the short 240Z insulator for use in the 280Z cars. Seems really expensive for what it is. The specs are probably way too precise. It looks like a wheel adapter.

Shiny and clean. Looks like you have an F54 block with the holes for the engine-transmission gusset. Designed to reduce NVH. I can't remember how the holes in the transmission case look though. Might not fit your setup.

It seems so. There's overlap though. Kind of doesn't make sense in light of the 5 mph requirement. The front bumper is usually hitting the back bumper of the car ahead. Bureaucratic nonsense. 1976 -

I think it was so the bumpers would be at the regulated height. Found an interesting Hagerty article. I've also read somewhere that part of the reason for the big bumpers was for insurance purposes. The insurance companies were paying out too much for minor parking lot bumper bumps. Can't remember where I read it but it stuck in my brain. A congressman was involved. They're called "safety bumpers" but the safety is for the insurance companies. 5 mph. https://www.hagerty.com/media/opinion/the-hack-mechanic/two-years-that-changed-cars-forever-1974-bumpers-and-75-smog/

Maybe you and @madkaw could share brand information about the VR's. Where did you buy them? Maybe they're all from the same batch.

Race car 280Z. Anybody seen it in action? No reserve. https://bringatrailer.com/listing/1976-datsun-280z-66/

Apex has had had delivery problems for quite a while. Better check the wait time. That Gold Line Brakes shop looks interesting. Worth a call or email. The seals are in the bore right, so the piston is the part that needs to be perfect. A rebuild kit might be worth an attempt, they seem cheap. Figure out where the piston will sit with new pads. Might be that your pads finally wore down enough to let the crusty piston surface hit the seals. You'd imagine that a Craigslist part needs a rebuild too. There's a reason they're not on a car. https://www.rockauto.com/en/catalog/nissan,1981,280zx,2.8l+l6,1209338,brake+&+wheel+hub,caliper+repair+kit,1720

Check the fuses and fusible links associated with the ignition circuit. You have exposed wires which might have grounded. And the Pertronix Ignitor can get damaged if the power is left on. Your wiring quality looks terrible. Spend some time making sure each connection is solid and insulated. There is a link in the Downloads area about how to test the Pertronix Ignitor. Once you get your wiring correct you might check it out. If you have power at the correct wires (test light or meter) and good grounds then testing the module would be on the list.

I thought "prancing horse" was Ferrari. Anybody know what this is about? https://bringatrailer.com/2022/12/01/bat-auctions-presents-the-z-collection/ https://bringatrailer.com/listing/1973-datsun-240z-223/

It's on BAT now. https://bringatrailer.com/listing/1970-datsun-240z-101/

Just for learning, I pointed out the contact points. That lever in the middle bounces back and forth between them.

The diffs are probably all the same if they are as they left the factory. But the mounting hardware could be different. The very early 240Z's had the differential mounted forward by a small amount, about an inch and a half I think. It caused vibration so they moved it back. So the mustache bar and the differential mount are different along with a shorter propeller shaft.

What's the casting number on the head? I circled where it should be. Post a picture of it, it will show if the head has been shaved by its distance from the surface. It kind of looks like it has been. Also, take a picture of the back of the cam shaft. There should be a letter stamped in to it. And take a picture of a cam lobe or two. You can tell if it's been ground by the size of the lobe.

The pistons combine with the head's combustion chamber volumes to determine compression ratio. The F54 used the P79 or P90 head. It has a larger volume than the N42 and N47 heads. The F54 and the N42 L28 engines have similar CR's. 8.8 and 8.3. The engine in this thread looks interesting, probably has more interesting parts. Probably should be rebuilt but if it ran okay before it could just be reassembled with a new head gasket. All from a tiny leak...

What is the engine supposed to be? You just kind of appeared from nowhere. There are some not-so-good things in the pictures but it's hard to tell what they are. You might clean up the piston tops and post another. Detonation can cause damage that looks like foreign object damage. It can also break rings.