Zed Head

Here's a link to one post in that ancient blog. The links to the source are at the top if you want to dig through more. It's on-topic but doesn't cover your question. Search "Bosch" in it and you'll find a good post from a Ford guy. Even Ford was color-coding injectors back then. http://yarchive.net/car/injectors.html

Here's a typical general reference, below. I think that finding Bosch injectors in your 280ZX is like finding a 10 ohm resistor in the coolant sensor line on your 280Z. Somebody like us either figured things out back in the 80's or a cross-reference list existed. I am 99% certain that Bosch changed their part number with the length of the hose. I think that the range ran from 105 to 120, as you can see in that spreadsheet. Until somebody finds that cross-reference, there will be no certainty, beside the reality that many people use them and that they work very well. I have another old source I can paw through, from a guy who who really understood the system, even suggesting modifying the AFM traces to tune it. He might have mentioned something. I'll have to dig it up though. It's good reading.

It's all about cost, skill, luck, and time. How much of each or any or any combination, do you have? Here's an option that looks quick, fairly low skill level required, but expensive. https://whiteheadperformance.com/performance-parts/datsun-240z-260z-280z-1970-78/240z-280z-diff-differential-axles-lsd/

No advice, just curious, but how bent is the head? The head on my 76 engine was bowed up in the middle about .008". I set it back on with no gasket and found that I could pull the bow down really easily with a single head bolt and a ratchet handle. Seems to me that having a bent head machined with a torque plate then bolting it to the engine to run it straight makes more sense than shaving material to get the surface flat but the valve guides off axis. Just a thought. I wonder if the requirement of straightening is really required. I never re-used the head so have no evidence either way.

There's this one - http://forums.hybridz.org/topic/127169-mfactory-r200-helical-lsd/ which seems pnp. Then there's the OBX, which takes some work to make sure you get the right one, and flip the gears, and replace the low quality washers inside. https://www.amazon.com/OBX-Helical-Nissan-300ZX-Silvia/dp/B00QHQWMQ6 http://forums.hybridz.org/topic/88099-obx-differential-inspection-and-installation/

I'll bet that the gear is cracked and that's why the engagement ring is loose on it. Maybe the dislocation is enough to affect the needle bearings. And/or whatever caused the crack also affected the needle bearing cage. I'll send that gear out. I dinked around with it but I couldn't get the gap to open or close. I'll send the needle bearings out also, just in case.

Here are a few references, but none specifically connect the 280Z to the data. It's kind of generally accepted that the Bosch 0-028-150-105 is the model for the Nissan injectors. The part number molded in to the Nissan injectors is the same for all of the varieties of the time, so it's not worth a lot. And the different part numbers for the early Bosch injectors seem to relate only to hose length, but the injector is identical. So, there's a range of early Bosch injector numbers that will work, with a hose length change. Anyway, these three links are worth browsing through. http://atlanticz.ca/zclub/techtips/injectors/index.html http://users.erols.com/srweiss/tableifc.htm#BOSCH http://www.witchhunter.com/injectordata1.php (hose end sheet)

The front case locks down the other end of the shafts. Clues seem to point to a bent shaft.

Looks like you made it past the two red battery cables. Good luck with it. The projects that don't cost you much if they get screwed up are the most fun sometimes.

Bumping, just because $12,280 is pretty good for a 76 280Z. Hagerty numbers make somewhere in the 20's seem reachable. Polish those treads... Six days. https://www.hagerty.com/apps/valuationtools/1976-datsun-280z

I just looked at my 4th gear (the one on the input shaft) and 5th gear and the "engagement ring" (been Googling, proper name) on those two is pressed tight against the gear. 3rd has the .014" gap. I wonder if it's coming apart. If you get yours to work I might give mine a little tapping with a hammer to see what's what. Did the gap close up tight on yours or just even up?

I'm tempted to try and pry the synchro cone off of a gear just to see if I can.

The owl or an identical one comes back every year. Then they raise a family in another box in the yard. After they kick the squirrel out (and maybe, eat its babies).

So the gear is the right one, but, as you might recall, this transmission was severely abused. I got it for cheap and used the front case for a 71C conversion. Here are a few pictures of the worn bearing surface and the blunted dog teeth. USPS will be cheap, I'll just send it under out under our last transaction, but it might not be usable for you. I did come up with another way to look at the wobble though. A feeler gauge in the gap between dog teeth and gear. I found that mine would take a .015" gauge all the way around but got tight for about 6-7 teeth on one side. Let me know if you still want it. The synchro surface looked worn too.

I highlighted what I think is a critical statement. It was at 15 but something changed. I went with the easy one of a misplaced hose. Another thing that can change, on its own, is for the breaker plate to get stuck in the advanced position. Broken Z and ZX breaker plate bearing assemblies are very common. One way to check is to reconnect everything then watch what timing does when you apply vacuum to the vacuum advance canister. If it doesn't move it's probably already advanced and stuck there. Or you can take the distributor out and examine it, and move it by hand.

Aren't you going to count them? I think I have the right one. Here's a little bit better picture showing what I think must be the splines used to lock the synchro cone on to the gear. I've noticed the pattern before but never really thought it through. Metal can stretch so maybe a good beating can actually break those two pieces apart. The back of the input shaft shows a really clear line. And a bonus picture of my neighbor, since he was out. Edit - some good micrometer or caliper measurements might pick up a wobble.

Did you mess with the vacuum advance hose? Maybe it's attached to the wrong port, getting full time vacuum. Try disconnecting it and see what happens.

I can't remember what 3rd gear looks like but I'm sure it's in the bucket. Let me know. Post a picture. Looking at the structure of the gear it wouldn't be surprising if it was a press-fit two-piece assembly. People say the whole gear needs replacing if the synchro is damaged, but maybe not. Maybe you can press it back together. If not, take it apart just to see what the innards look like.

I clicked the links and it just re-opened the thread. Not sure why. Here's an attempt at a fix. Edit - took out my links to shrink the page since cygnus fixed his.

I think I might have a new clue for you. It's one of those things we don't really think about, like getting the wrong collar for the throwout bearing. The engine is actually involved in locating the input shaft, through the pilot bushing in the crankshaft. Without that locating and support function the input shaft can **** and wobble inside its bearing. There's really nothing keeping its axis parallel to the other shafts without it. I remember thinking about that when I took a transmission apart years ago. The shaft is short and the power is transmitted through the coupling sleeve to the output shaft. But there's not a whole lot supporting it. It really looks all loose and disjointed when you ponder it. In short, your drill drive test procedure, while brilliant, may be flawed.

You should have made mention of the video. Would have looked sooner. Sounds terrible! I would use input, output, and counter- as the shaft designations. One possibility that might be possible is some sort of problem at the interface between the input shaft and the output shaft. The "direct drive" fourth gear path. Also, could it be possible that one of your coupling sleeves is partially engaged? Maybe a problem with a shift fork. Or maybe one of the inserts inside a coupling sleeve is out of place, maybe missing a spring or something. Spitballing...

Could you have cocked a bearing when installing? Maybe try the test with the front cover removed. Then you'll only really be using the adapter plate bearings, assuming that the front bearings aren't rubbing on something. Which you'll be able to see. Could also be a problem in the front cover. The nose can get bent or damaged.

Doesn't look terrible. Looks like maybe it had a collar of rust catching the edge of the piston, holding it in. I had a thought, that doesn't help you now but might someone else. I think that you could have blocked the brake line and the bleeder holes then filled the cavity with a low compressibility fluid, like water, oil or grease, and then pressed the other piston in with the C-clamp to generate pressure. Or popped it with a hammer. Just a thought about another way. If you pop it with a hammer you'd get a much faster pressure increase so leakage wouldn't be so significant. And the stuck piston would fly a lot farther when it came out.

The gear in the drawing could certainly go on backward. I have a vague memory of somebody mentioning that in a different thread. Might have been duragg over on Hybridz. He got so deep in to building his transmissions for 7000 RPM shifts that he was hand filing the synchro gears to perfection. Here's a EuroDat at, he probably has a thought. @EuroDat

Don't overlook the often overlooked ground circuit. Bad ground, bad sound.