Zed Head

I came across another variable reluctor system. AMC. Very similar to Nissan's in concept but not so bulky. Also switched to a fancier module as it progressed. https://www.rockauto.com/en/catalog/american+motors,1976,hornet,4.2l+258cid+l6,1004500,ignition,distributor,7108 https://www.rockauto.com/en/catalog/american+motors,1976,hornet,4.2l+258cid+l6,1004500,ignition,ignition+control+module+(icm),7172 https://www.rockauto.com/en/catalog/american+motors,1978,gremlin,4.2l+258cid+l6,1003936,ignition,distributor,7108 https://www.rockauto.com/en/catalog/american+motors,1978,gremlin,4.2l+258cid+l6,1003936,ignition,ignition+control+module+(icm),7172

How do you know it's #6? The brake booster supply hose is back there, and the heater/AC valve vacuum supply. I've noticed that the intake air supply across all six is not even. #1 tends to run lean (whiter plugs, more air), and 5 and 6 tend to run rich (dark plugs, less). Could be too lean from a vacuum leak or too rich because of design.

I wouldn't assume that whatever you might find needs a rebuild. Look around for a complete junked 280ZX or 280Z. Buy the whole car and scrap the rest for $50. As far as the 71A the car will probably be worth more with it installed. Not clear what your long-term plans are. Your problem description makes it not clear what exactly is wrong with it. Might be a simple fix, who knows. Don't overlook just buying a cheap 71B 4 speed while you look for a long term solution. Sometimes people give them away. @Racer X has what you need, probably of all three varieties, but it might take some work to get to. He's right down the road...

Post #33

The external regulator acts as a relay for other relays. When you take it out of the picture and use some of the various wiring diagrams out there for converting you end up closing the circuit to the other relay without realizing it when you jump those wires. The L pin on the externally regulated alternator is a path to ground. So if you see voltage on the wire that connects to the L pin, after you wired the jumpers in, with the key off, then the voltage will have a path to ground with the key off. The S pin sees voltage all of the time, normally. It is not a path to ground. Here's 1982 -

This part does suggest either a bad alternator or a device on the L wire, like a relay, that is powered by the newly jumpered wires. It would be on the L circuit. If you measure voltage on the L wire with the key off then the problem is in your wiring. I had this problem on my 76 with the brake warning lamp check relay but I don't know how the 71's are wired. It should show on a wiring diagram.

You don't have to wait for the new alternator. SteveJ's tests are for the harness. The wire that goes to the L terminal would have to have voltage from the battery in order for the battery to discharge through the Lamp circuit. if the alternator is okay. Put your meter on the L wire in the harness and see if it has voltage with the battery connected and key off. The S wire will always have voltage and could only cause a draw if the alternator had an internal short. Don't overlook that the original wiring might have other devices on the L circuit. S and L are the labels for the internally regulated alternator systems. The top of the T is S, the upright is L.

You can use a meter to see if there's a short through the alternator. You should be using a meter anyway when modifying wiring.

The BAT people take a lot of abuse over that, reporting the correct numbers. Surprising that they did not call it out in their description. As I understand things, BAT writes the description, not the seller. On the other hand though, anyone that follows the 240Z auctions knows to verify that. The bidder, MRM, has bought and bid on several 240Z's. You'd think that they knew what they were bidding on. Who knows. Drama! https://bringatrailer.com/member/mrm/

The market is a combination of enthusiasts (the V8 car went for a good price), collectors (the imperfections detract), and investors (the low VIN number has inherent value that will increase as time goes by). I think that the investor class is growing as the stock market loses value. Hard assets bought by investors who like neat cars. Here's the BAT price plot for 240Z's with a limit of 60K. The trend is still up. Even the low end is up.

The brass nubbin modified switch could be tested with an ohm-meter. If you're waiting to install it to test it with power. Actually, it should be tested with an ohm-meter before applying power. The comment about shorts and erratic device operation are interesting but there are no details. Can't tell what exactly was done.

The Z money is coming back. Three in the 30's, a wide range of styles. https://bringatrailer.com/listing/1977-datsun-280z-84/ https://bringatrailer.com/listing/1972-datsun-240z-255/ https://bringatrailer.com/listing/1972-datsun-240z-201/

LOW VIN NUMBER ALERT! LOW VIN NUMBER ALERT! 🚩 🚩 🚩 https://bringatrailer.com/listing/1970-datsun-240z-96/

My mistake. I was thinking of the front cover. Also remembered some old stuff about the reverse switch. I think you mentioned it in your other thread about doing the rod instead. http://zhome.com/ZCMnL/tech/240SX5spd/Transmission2.htm It's not obvious in the first picture below but he's showing both positions filled with a switch. The original hole and the new hole.

I thought it might be. It's just how he rolls. Hasn't changed. Put a magnet on it to see what it is. Doesn't really matter for your purpose but will confirm zKars's theory. Actually, all he (or the guy that does his work for him) had to do is what zKars's described in his thread, posted above. Weird how that circle got completed...

Big money for a resto'ed 73. It even has the splash pan underneath. Crazy 8's... https://bringatrailer.com/listing/1973-datsun-240z-205/

The videos were telling. Looks like somebody cobbled some parts together and didn't get things completely right. You could make your own switch up on the shift lever. Wouldn't be too hard to do. Where'd you get the transmission? To zKars's point - is the front case with the switch holes iron or aluminum? WRONG!!!>>> I think that the 4 speeds were all iron.

If it's doing the opposite then you must be seeing the other end of the indentation. Not sure how that could be unless the rod moved. But the striker shouldn't work correctly then. @zKars knows more. I'm just eyeballing the drawings and parts and moving things in my brain. You said earlier that sometimes it's difficult to get in to gear. Maybe that's a clue.

I get an error message when I try to watch the video. You might upload to Youtube and post the link.

From the FSM

There are detent balls/plugs/springs in the adapter plate that hold the rod in the proper position. Things would have to be way off to get the ramp in the wrong place.

Looks like the correct hole. The switch button would sit right next to the ramp edge. Just a tiny movement moves the button. Before you start filing away at the button you could just thread the switch in to the hole partially. You could use a meter to see when the contacts close then back it off a thread. Then put the transmission in reverse and see if it works correctly. If it does then a washer or some filing should get you there. This is what you should see in the hole when it's in reverse and not.

It's not common but occasionally the roll pins that hold the fork to the shaft break or fall out. You can see them in zKars's pictures. I'm not saying that's what is happening in your case but the transmission is a very mechanical device. Gears and rods and other parts made of steel and aluminum. If it worked before and it's not working now, that implies that something moved. It might be that the switch contacts are so close that a fraction of a millimeter has caused it be on all of the time. Who knows. You could get your eye or a camera up by the hole in the transmission and see what's in there. If it still looks like zKars's pictures then it's probably the switch. Funny, but one of zKars's roll pins looks like it's working its way out... @zKars

Here are some pictures of the area of the rod that moves the switch.

Have you tried connecting the electricals with the sensor removed? It's not clear that the switch itself isn't stuck. There's not much to it. The rod has a section cut out with a ramp. The ramp pushes the switch contact point closed when the rod moves. If the switch is good the only other reasonable possibility is that the rod is moving inside the fork. That would not be good.