Zed Head

No. You're right it's an engine mount. Bad text in the eBay ad. The part number is for an engine mount. The eBay listing shows 70-73 240Z, but an engine mount should fit all S30's. So that eBay listing is completely screwed up, sorry for the misdirection. So many ways to go wrong on internet sales. OReilly 104-0828 - http://www.oreillyauto.com/site/c/detail/BA00/1040828/02327.oap?year=1983&make=Nissan&model=280ZX&vi=1209406&ck=Search_02327_1209406_-1&pt=02327&ppt=C0019#compatibilityTab_ I bought the type that looks like yours but must have a different bolt pattern. Good luck.

Here's my latest guess - somebody transplanted a CLSD from the front axle of a 4x4. Looks like they had a variant of the R200 with a side tube to hold the axle. No need for clips. http://www.nissanpathfinders.net/forum/topic/40656-r200a-vs-r200awhats-the-diff/ I found it while searching for "R200 side gears", which came up with a bunch of stuff. Maybe you can swap those side gears. Worth searching. Otherwise, I think you're kind of screwed. It looks like one side of these might use a clip though, but who knows what other variations are out there. You might take it to a local 4x4 shop. Those guys break so much stuff that they know their diffs inside and out.

@SteveJ

240Z world. I wonder if one's an automatic mount and everyone is using the same stock photo. Or maybe they had to switch when Photobucket screwed them over. Autoplicity's picture seems right. http://www.ebay.com/itm/Beck-Arnly-104-0828-Motor-and-Transmission-Mount-/361572098485?fits=Make%3ADatsun|Model%3A240Z&epid=76417723&hash=item542f6061b5:g:sE0AAOSwEzxYZ0s5&vxp=mtr

That's not the one I got. You could go to the store and check it out. The internet makes us all forget about the old days of walking into the store and looking at a part to see if it's right.. But eBay works too. Sometimes I check the local weather at my computer when all I need to do is get up and go open the door...

Nissan calls that mount the rear engine mount. It's the only thing that keeps the engine from titling forward when you hit the brakes. I replaced mine with an Auitozone Duralast brand. It made the shift lever feel more solid. Definitely raised the back of the engine too, probably stopping some driveline vibration. I've never seen a urethane replacement for that one, although there are replacements for the outer ones on the 280Z. You don't have those on the 240Z.

Gawdammm... I was inspired to crank up my ancient 200 disc CD player and search out that old album. I have the vinyl but no turntable. I've heard that cassette tapes are making a comeback. I'll bet there's a play here to sell to one of the big boys. http://www.bbc.com/news/technology-40492668

My discerning abilities are incredible...

I'm thinking about making tools in my backyard, labeling them as Made in China on them and selling them on eBay. I think there's a market. No refunds.

But you probably paid $5 at Harbor Freight for that, right? That's the heart of the problem.

Interesting. Maybe there's a diff that uses bolt-in axles like those for an R180 that will swap in to an R200 carrier. Are those holes in the center piece threaded? I asked that earlier when I thought it might be an R180. If they're threaded, the threads would have had a purpose. Edit - never mind, I see that that's just the end of the other axle. Weird thing that you have there.

Good luck with that. At least you have a "first place to look" next time.

China and USA both bad? Can we get Made in Canada? Where do we turn? Oh god, the path down is getting so steep... Edit - wait a minute. I thought Canada was frontier, where people made their own tools? Fire up that forge!

How long are you letting it idle? Not clear if it's idling for ten minutes or ten seconds. Could be that the new fuel pump doesn't actually have power and the engine is just starting on residual fuel.

Shouldn't be a problem. Can you get some vise-grips on the heads instead? Might be able to break them loose that way. Once they break loose a screwdriver might work.

Just bend the four little crimps back, a pair of pliers works well, and pry the top off of the plastic base. Work over old newspaper or similar so the rust doesn't get your work bench dirty. Edit - there might be a ground wire connected to the metal cover on one side. I think that's why my picture has the cover just tilted open instead of removed. Post a picture...

There's a constant battle going on between engineers and materials people, and between design and manufacturing. The Nissan design looks like a typical "make the cheapest material work" design. Typical automotive principle. Nothing wrong with it, it worked. But it's a complex design so without the tooling, will be difficult to reproduce. Whiteline's product looked promising, and the use of materials as the vibration damper instead of the design looks right.. I think that they just did a poor job of selling it. I'll see if I can find that thread I mentioned. Found it. The Advanced Search engine of the site actually works pretty well! Needs promotion. Edit - found their site from the picture inthe other thread. Looks like they just stopped making the mustache bar bushings. Maybe they're falling apart? Maybe MSA can be a supplier if they come back. https://whitelineperformance.com/amfinder/?find=1976-nissan-280z-base-128907

Weird. I noticed that the grooves didn't seem obvious in your pictures. But they didn't seem that obvious in mine either. jmortensen knows a lot about diffs. He might have some thing to share.. @jmortensen

C'mon Euro, you gave in! Now we're just a service, like Google.

Motorman, all those 240Z's and it's unfamiliar? Buschwacker, just having fun. But you have to share more. Otherwise, it's work.

What kind of car is it going in to?

Vagueness leads to more vagueness... But it's fun for us. Welcome to the club! The answer is - one still has the crossmember attached.

Are you on a phone, where you can't see the pictures or download the FSM? It's all there... Tapping is unlikely to help. But good luck anyway, you never know.

Actually, those three get power from the ignition relay. My car had a mysterious blue wire to the ignition switch in addition to that box of rust. The relay is over by the fuse box. There's a diagram in the FSM, BE chapter. The 280ZX igntion relays will work, they have the same pins, but have an extra dedicated ground pin also, so they get a different part number even though the'll plug right in. Nissan moved the relay to a dry spot behind the glove box in the ZX's, I got a spare from a wrecking yard. I replaced my 76 with a 78 though, that I had from a parts car. Somehow it survived.

Whitehead used to sell Whiteline low durometer PU bushings but it looks like they ran out of stock. They removed the listing, with no reference (poor web site management) and other web sites show "out of stock". Somebody just reported installing a set, but I can't find the thread. It was recent. He said they were quiet. https://whiteheadperformance.com/product/whiteline-differential-moustache-bar-bushing-kit-w91045-datsun-240z-260z-280z/