kcpope

I used the one from vintage rubber, and I was happy with it. I think it was $150 or so, which is a good compromise compared to $400🫤 I installed with dash in place using the typical rope method. As far as removal, carefully remove the stainless trim pieces, then use any manor of razor blades, putty knives, flat heads, etc to remove the old brittle rubber, being careful to not chip or crack the windshield.

As far as I know, nothing wrong with this approach. I think many folks have had to do this. Kinda a bummer to bend the factory lines, but hey, gotta make it work.

Your brake master cylinder should not have any gasket between it and the booster. There is no fluid or air pressure passing between these two parts, hence no gasket or seal. You likely have a leaky master cylinder. The rubber o-rings inside the master cylinder can leak, causing brake fluid to exit the rear of the master cylinder, then it leaks through the (non-sealed) mating surface between the master cylinder and the booster. It then dribbles down the outside of your booster and causes the paint peeling you're seeing. I'd start with a new master cylinder or get your existing one rebuilt. Keep in mind, you have an early 71, so make sure you verify the reservoirs are in the correct orientation on any new master cylinder you get. There was a change in 1973 (i think) that swapped the front and rear reservoirs. For a 71, I believe your front brake reservoir is in FRONT and the rear brake reservoir is in the REAR. in 1973, the designed changed and those were swapped.

Still fiddling around with it… Does anyone know what this solid black wire is for? Comes out of the factory wire harness at the coil. It’s the only wire not connected to anything for me. Maybe the ground wire for the old points distributor?

Yeah, radio interference, I’ve heard that too. I figured that same interference might be messing with the tach. It’s a long shot, but at this point I figure, why not 😅

That’s within spec for your primary. What’s your secondary ohm reading? also, are you running the little stock condensers? One at the coil. One near the alternator. I’m going to try adding mine back in and see if it makes a difference.

Yeah, I’ve read mixed things regarding the coils. As Zed mentioned earlier, the 280zx dizzy wants to see around 1 ohm resistance, which is exactly what I have. Did the ZX also have a ballast resistor? In general when people convert a 240z from points to electronic ignition, here’s what I’ve read: if you’re using a 1.5 ohm coil, add a 1.5 ohm resistor as well. if you’re using a 3.0 ohm coil, no resistor needed. This seems to be the case if you’re doing a pertronics ignition, but I’m not sure if the same applies to a 280zx dizzy…

Agreed, I’ll do my best to get to the bottom of it. I’d love to not have to swap tachs. We’ll see.

Thanks Steve. If I do the swap, I’ll adapt the 260z tach guts into the 240z housing to maintain mounting points and the correct font as zed mentioned. But before I do any of that, I’ll try pulling the existing tach out and see if I can see any obvious problems. As I’m thinking about it more, I’d be suprised if the e12-80 is failing. The engine seems to run too good for that to be the case. PS: the whole reason I needed the tach was to sort out my vacuum advance timing as I mentioned in my other thread. I went ahead and bought a cheap optical rpm gauge on Amazon that I’ll use in the meantime. At least I can get my timing properly setup, then move on to fixing the tach.

Good info, thx. I’ll read up on other threads regarding everything needed for the tach swap. Yes, my E12-80 module is factory Nissan. I’m intrigued by the GM HEI swap. Could that be a permanent solution if my tach ends up working with it?

Welp, I tried both options I described above. No change. Only thing I haven’t tried is adding the condenser back in the wiring. I’ll give that a shot. Also I didn’t realize that the tach can be pulled without removing the dash. That’s a bit of good news. In the meantime, I’ve found a good deal on a tach from a 260Z. Can anyone confirm if those are voltage driven just like the 280z tachs?

Thanks for the info. Interesting. Before I do that, I’m going to try 2 things: 1. Adding a ballast resistor back in with the existing 1.0/12400 ohm coil, and see if that helps the situation 2. I found another coil laying around in my old man’s garage. 1.3 ohms primary, 10600 ohms secondary. I’ll try this coil with and without the ballast resistor as well. Let me know if anyone prefers option 1 or 2 better.

***edited my above readings because I wasn't reading my multimeter correctly the first time*** Here's the correct coil readings I'm getting: Primary: 1.0 ohms Secondary: 12400 ohms So this coil appears to be within the specs that Zed Head posted.

Good info Zed, thanks. That said, I really want to eliminate all other possible causes before having to pull the dash to get to the tach. Like I said above, I confirmed my wiring at the coil is correct according to the video SteveJ shared. So what's left to test? I decided to check my coil and here's what I got: ***edited because I wasn't reading my multimeter correctly the first time*** Primary: 1.0 ohms Secondary: 12400 ohms Any smoking gun with that info?

@SteveJ @cgsheen1 Ok, I followed what both of you said and watched the video. I tested everything with my multimeter and can confirm that my wiring was correct. My B/W wire with 12V (key on) is connected to the G/W wire. The B/W with no voltage (key on) is connected to coil positive. No changes made. Thoughts on what to check next?

Cool, thanks for the info, I’ll consider buying that. But before I do, is there anything I can test to confirm the coil is the problem and not the wiring?

Onto the next thing… Yes, I know I’ve got several other threads that aren’t resolved yet, but I need to solve this issue before resolving those issues🤦🏼‍♂️ First of all, thanks to everyone whose been so helpful to me in sorting out all these gremlins in my Z. I drove it for the first time today after slowly building it over the past year. Seemed to run well, but not quite all sorted out yet… 1972 240z, L28 with SUs. My tach isn’t working right. I have done the 280zx dizzy upgrade, and wired it according to this diagram… I do not know much about the coil, but I suspect it’s from a 280Z because the engine was L28 swapped at some point. Car starts up very easily and runs well. The issue is, the tach is reading about half the RPMs that the engine is actually spinning, and seems to become even more “lazy” as the revs increase. What might cause this? Where should I begin? One thought…the wiring harness at the coil has (2) B/W wires. One gets spliced together with the G/W wire. The other gets connected to the + terminal on the coil. How do I know I didn’t accidentally reverse these? How would I test that? Here’s my current wiring setup…

I bought this one initially, because I needed the housing and keys because my car didn’t come with them. https://zcardepot.com/products/ignition-switch-with-keys-240z-260z-280z-510?_pos=1&_sid=af74c7332&_ss=r then I bought this ignition switch as my replacement, but retained the ignition housing linked above. Oops, thought it was standard motor products. Its actually beck/arnley… https://a.co/d/c9Eg5sX

I’m an idiot, and was testing continuity to ground while the BY starter wire was connected to the solenoid, so of course it showed continuity. Removed it from the solenoid spade, no continuity. Anyways, that was just an aside rabbit hole… Received the new ignition switch yesterday. Boom, turned over just like it should. Bottom line, the aftermarket ignition switches from cheap unknown brands (sold through zcardepot), might not be great quality. This new one I got from Amazon is “standard motor products” brand and will hopefully last longer. Nonetheless, I learned some new things on how the ignition switch is wired to the starter. Special thanks to @SteveJ for all the pointers.

Another question, doing some further testing. Should I be getting continuity between the BY wire at the starter solenoid and body ground? Because I currently am. 🧐

Thanks! Yes, I agree. It should be the K18. To temporarily bypass the K18, what other jumpers should I make other than the one jumper I showed in the video? Just ground connection the 3rd BY wire? Also, could you post a link to the full size version of that 1973 electrical schematic?

Hi Steve, Ok, followed your direction. See the following video and let me what you think. Also, didn't mention it in the video but the jumper wire for the auto trans interlock is still in place and functional.

Signature updated, thanks. 1972 240z with an L28 with SUs. Car was originally an auto, but I 4 speed manual swapped it. I jumpered the auto trans interlock wires together as described in other threads. I also have the firewall mounted "K18" relay mounted and plugged in next to the battery. And like I mentioned, it was cranking over and starting up just fine this past weekend.

Hi Steve, I was hoping you would chime in! At the ignition switch plug, I have 12V from the WR to ground. brake lights work, hazards work, running lights work, engine inspection light works. I don’t have a cigarette lighter or horns hooked up to test at the moment.

To confirm it’s a faulty switch, I said to myself, well I’ll just jumper the wires on the plug that normally plugs into the back of the switch, thus confirming all my wiring between the switch and the starter is OK. Essentially “hot wiring” the car. According to the factory wiring diagram, with the key in the START position I should have power at WR, GW, and BY. So I jumperd those 3 wires together, thinking it would crank the starter. Still nothing. Any reasons this shouldn’t work?