Zed Head

Not with ported vacuum. Ported vacuum sources pull no vacuum at idle. So there's no need to remove the hose. I've never found a good description in the FSM's of where Nissan sourced the vacuum for the distributor advance. Most emissions era cars would use ported vacuum since it gives retarded timing advance at idle, and retarded timing is cleaner. You can tell if it's ported by just removing the hose while the engine is idling. If nothing happens, it's ported vacuum. It's always been a hot topic.

I saw it more as a translation error. Reverse and return are very similar in meaning. The striker guide and the plunger affect all of the gears since all of the gears need the striker rod to rotate for engagement. I don't see how it could affect just reverse since it's out of the slot as soon as you move the shifter sideways. Looks like it's designed for the plunger to center itself when it's close but otherwise the rod and guide moves freely once the plumger is out of the slot. I'll bet a person could get the bolt spring(s) and plunger removed with the transmission in the car. Hard to tell though if the plunger won't fall in to the housing. But you'd know what it was affecting if you did remove it. The check balls control fore and aft motion. Copied the 4 speed drawing, the 5 speed drawing doesn't have the labels for some reason, in 1978.

Poop and laughter. I went to my old standby, the carparts.com site and searched around for the part numbers to see if I could find some images. Found some on an Arabic langauge site. It's odd, the numbers match but the label says "plunger reverse" not plunger return. Anyway, something to look at. p.s. I browsed around some rebuild videos and it's funny how nobody really pays any attention to the parts in the tail shaft case. https://www.carpartsmanual.com/datsun/Z-1969-1978/power-train/transmission-control/5-speed https://haraj.com.sa/1117916900/قطع_قير_دتسن_80_85/

This is one of the confusing things in the first post. Is the guy actually seeing a spring or is he feeling a return-force and assuming a spring? I wonder if the return spring plunger #11, and/or the groove/flat, suffer wear over the years. Seems like they would be under high pressure, with a small contact area and high leverage. I'll bet that's a strong spring. New rabbit hole!!!

Seems like there's only one spring but it does both left and right. Doesn't it? It sits on a flat (maybe a groove) on the "striking guide", and rotation of the guide takes it off of the center of the flat. The spring pushes on both sides though to bring it back to center. If I'm readng the drawing right. 9, 10 and 11. p.s. it probably only has real effect when the guide is near center, with the plunger falling in to the stable position. The whole Facebook conversation might be revolving aronud a misunderstanding of how it works and what is possible.

Observations and comment. The Facebook link would probably help or the text copied and pasted for us non-Facebook people (there are a few left). And, you went 1-2, 5-R, right-left, 3-4, right-left. Hard to follow, besides use of the word "gate". Not sure Nissan's system would be considered as having gates. Also, without the Facebook post "same thing" is undefined. Not clear what the problem is that's being discussed. Are the springs not shown in the FSM control drawings? Only posting because tranmsission stuff is interesting, and I like to practice my reading and comprehension. I could be off.

Manifold gasket? Hey, on the problems bleeding the clutch system - I discovered that you can push the slave cylinder back in its bore by hand from underneath or by reaching down inside the engine bay. Crack the bleeder, push it back using the rod to remove the air. Easier than messing with the pedal. I also had a bad slave cylinder that I could not get bled. I never really figured out for sure what was wrong with it. I think that it might have been sucking air in through the seal. Can't understand how unless the MC return spring was strong enough to pull negative pressure. Anyway, replacing the slave cylinder fixed it. p.s. I remember that there was a small amount of fluid under the dust cap. But there shoudl have been more after many pumps. Had to be sucking air on the return.

The single spark indicates that the coil has power and ground. The fact that there are not more sparks indicates that the points are not opening and closing. Breaking and making the circuit through the coil. Could be that the cam on the distributor is worn out or the points are not set correctly (held open or held closed) or the distributor shaft is not turning. With the key on and the distributor cap off it should be possible to open and close the points by hand and get a spark each time from the center wire of the coil. The rubbing block of the points needs to be on the cam point when setting the points gap. From about 1:00 https://youtu.be/BC3nmuXdEuI?feature=shared

Sounds like the distributor shaft is not turning. Take the distributor cap off and watch the rotor when you crank the engine. Maybe the drive gear has slipped. It happens, apparently.

If there's no spark with power directly to the coil then working on the wires under the dash won't help. Study the diagram and you should see. Did you test for spark from the coil's main output wire? The center wire?

Seems like you might be overwhelmed with ideas. Pumping my own suggestion here, but a simple length of wire will allow you to split the whole system in half. Seems like the cheapest easiest quick and dirty diagnostic. No oscilloscopes nevessary. No offense intended to the scope suggesters. But it seems early for that level of tool. If it doesn't start, focus on everything after the coil positive post. If it does start focus on everything before. Don't forget that you'll have to remove the wire to kill the engine.

I found your Ford doppelganger from 2021. https://www.ford-trucks.com/forums/1656335-91-f150-losing-spark-intermittently.html "There is nothing I could find on the Computer that indicated where it came from or what calibration it is for. The only thing it had was a QR code that directed me to a site called "installapart" but the site itself looked closed."

Hot wire it. Run a jumper from the battery positive to the coil positive post. It it starts and rnus then you'll know that the distributor and coil and points are fine, and you can focus on the wiring and tach. Not sure I saw rotor and cap discussed. It might be that spark is being created but it's just not making it to the spark plugs. Hitting Submit even though Yarb has replied. Let's see....

This one has a Reserve. #682. https://bringatrailer.com/listing/1970-datsun-240z-129/

Try bypassing the resistor and see what happens. Jump it end to end or just move the one on the end of the resistor to the Start post. It is bypassed on the Start circuit so you might be right about the bad coil. Maybe the coil is weak and needs full current to create a spark. It will be another clue if it works. Could be a bad coil or it could be a bad ballast resistor. Or put the old ballast back on.

grannyknot's build car sold. Pretty good money but I thought it would get more. https://bringatrailer.com/listing/1972-datsun-240z-342/

I seem to remember oversize pistons being hard to find a year or two ago. Looks like the supply has been rebuilt. Good news for engine rebuilders.

That's normal if the points are closed. There is a resistance test for the coil. You might try that first. The single spark actually makes sense if the coil has a circuit to ground continuously. When you turn the key on the coil is energized. When you turn the key off it is de-energized and a spark results. It is a clue that you have a short to ground somewhere on the wires after the negative post of the coil, or the points are not opening. Check all of the wires after the negative post, and the points, and the condenser. Make sure that they are connected correctly. A shorted condenser would do it too. You can test the condenser with a meter also. It should have OL, Open Line, infinite resistance on the meter reading. Even though it is connected to ground it does not pass any current. Remember, new does not mean good.

How can you tell that they're for an L24? I Googled the number and found this Rockauto listing. Looks like the Facebook guy might be one of those resellers. Easy money! https://www.rockauto.com/en/moreinfo.php?pk=4803141&cc=0&pt=5620 p.s. I can tell where you live, what you've been doing and numerous other things from all of the extra Facebook code in the listing. 😎 Seriously, what is all of that extra stuff for? Makes me wonder. p.s. 2 - the application does come up on the Rockauto page. What would we do without Rockauto?

If it was brazed it might be debrazeable. But you'd probably have to take a chance on destroying the base metal to find out. https://jfdbrazing.com/ten-steps-for-a-successful-brazing-operation/#:~:text=10 – Separating a brazed joint,easy to separate the components.

I asked a whole bunch of questions about type of weld in that same long thread. Posts #102 and on are interesting. Some thought spot weld some thought linear weld. I think consensus was though that they were all ugly welds. Also, some wondering, on my part, if it was welding or brazing. I don't think that MIG was common back then. I think that the end conclusion was that it's a complex joint. I don't that there's a way to make a clean straight cut because there is overlapping metal. You have to sacrifice one or the other side.

Not clear what you mean when you list those numbers. The first three pairs are AFM pins. Were you doing the AFM test procedure? Not uncommon to have the plug fall off of the bottom of the AFM, since gravity is pulling on it and the clip sometimes doesn't get clipped in when you reinstall the AFM. It might just be that the AFM plug fell off of the AFM and the bullet connector over the intake manifold for the coolant temperature sensor is unplugged. One big plug and one small one.

I was trying to be humorous but came off as scolding. Sorry about that. I'm sure that cgsheen just got his condensers mixed up. He knows a lot more about electronics than a simple condenser problem would require. Some of it's in his sig. Still waiting for bluez to give us an update...

I wonder what happened to Joseph and Koni Lee.

Your comment about wrongess is wrong. WRONG! Just kidding. Actually cgsheen's comment was only partially WRONG!. Disconnecting the condenser is a good idea. The points won't "burn" immediately. And the part about grounding (shorting) is RIGHT also. Commenting about somebody's wrongess almost always goes wrong. Like this post probably will. Right?