Zed Head

In sum - not sure what you're describing.

I don't really understand this part either. How can you confirm that the wipers operate if the linkage isn't installed? What moves the wipers?

Sorry, I got lost in the description and didn't see this part. Seems like a binding issue. Sometimes people install the linkage with the motor shaft in the wrong position. I think that it might also be possible to get the linkage installed in the wrong orientation. Pretty good drawings in the FSM. Have you confirmed proper installation or did you put it back the way you found it? Also, you might try running the wipers through their motion with them off the motor shaft. If you can't do it by hand, the motor probably can't either.

That's a sign of a weak motor. Mine would get stuck occasionally, even after I had it rebuilt. It Before you take it apart again, you might lift the blades off the windshield (stand them straight up) and try it. This will be essentially like no wipers but will be minimum effort required. Might remove the weird factor and replace it with weak.

An actual resistance number would be informative. You can't tell much by color. The other half of a "melting" problem would be heat dissipation. Heat is produced in all electrical components. My point is to look at the complete system. It's not just the material used, and as you pointed out, materials and their qualities can vary. All we really know about these "buttons" is that one looks like "carbon" and one is yellowish in color. long with that is the fact that many aftermarket perfromance parts are sold on old reputation and are, in effect, just brand names now. Quality has been lowered to maximize profits. Could be that 123 chose an inexpensive supplier. The original failure described was with the 3 ohm system. Definitely not high energy. Current flow should have been relatively low. The replacement parts might have damaged the 123 module, but the cap was already damaged. I'm using the stock GM HEI module with the stock GM HEI coil on the stock Nissan 280Z distributor and cap. 20,000 + miles, no problems. No need for an aftermarket coil, the stock GM system is plenty. I like to dig in to the real numbers behind these issues. It's just fun to do. Edit - overlapping posts. I see we're all headed the same direction...

Destroyed distributor cap buttons does seem to be a problem with the GM HEI distributors but conductivity differences between "carbon" and "bronze" materials seems unlikely as the cause. Arcing and/or bouncing due to a weak spring and poor contact seem plausible since that would produce heat. But straight-up heating of the button from high current and resistance-heating, without overheating the coil or ignition module doesn't really fit. Just saying, check the other parts too: the spring strength and the contact point, and maybe put a dab of conductive grease on the point. They're probably more important than the button material used. Edit - forgot about the other half of the contact. The rotor (also sometimes called a "button") contact. It needs to be smooth and conductive also. That tiny little area is usually overlooked.

SteveJ will probably figure it out. I forgot (again) that 1974 should have stock Nissan electronic ignition. The introduction of electronic to the Z's. Always good to confirm though, people do swap. Is it the stock unit, down by the fuse box, or aftermarket? Just trying to help. It's the details that will solve the problem. Pictures would be great.

The dual point problem is a problem. Apparently, it's for emissions purposes. It keeps idle speed up until the engine warms up. If you can live with a few minutes of low idle it's not a big deal to switch to a single system. My 76 had two magnetic pickups, electronic. Good work on the torch. I didn't see this until it was over but the bolt threads in to the transmission's aluminum housing so a torch would expand that well. ZTherapy is the source for carbs - http://www.ztherapy.com/

Look under the distributor cap and describe what's there. We can't tell what " as far as I can tell" means. How long is "will not crank back up"? Seems tedious but the words are all we have. Make them count.

My Posi Quiet pads (or maybe just one pad) started squealing very loudly when cold after the car sat in the garage for about a week. Maybe started by some rotor rust. After they warmed up, no more squeal. After a few days of driving the squeal dropped to almost nothing. Maybe a hard spot on the pad material. Just an update. They're not perfect. Thought I was going to have to put the factory shims back in.

I replaced the "rubber" backed Home Depot carpet with another that was a more typical sewn/glued fabric backing. Made a huge difference. The rubber was probably PVC with plasticizers, and they were vaporizing and redepositing on the windshield. The windshield still needs more cleaning than my other car but much less than before.

Just to add to your concern - in a discussion about wiping cam lobes (the bad wiping, like destroying) one of the engine builders described damaging the lobes just from turning the engine by hand. He could see things starting. Best to keep things over-lubed with the zinc additive lubes. Pressures at the rocker arm - cam lobe interface are still high, even at low speed. The old safe/sorry conundrum.

A maybe helpful comment - the ECU's usually go completely bad, either running super rich or not running at all. Your lean popping symptoms indicate the need for more fuel, which is not a common bad ECU symptom. Also, I notice that you mentioned electrical testing but nothing about fuel pressure. Another potential cause. Anyway, good luck.

Your time, and your money. Might as well send the money to a member though. wheee! seems like a good guy and could probably use it for his project. Post #4.

Fascinating that so many of us adjust the AFM to try to fix this problem. I did the same when I first got my car and ended up buying a new one from MSA. But my test numbers were way off. Still I might have been able to make it work using the other atlanticz Z "tweak". I have two, maybe three, AFM's that needs this tweak to work. It's the most direct way to get it done. http://atlanticz.ca/zclub/techtips/tempsensorpot/index.html Forgot to say - put your AFM back where it was. Blue's technique is for recalibrating to factory specs., not tuning. Many people just read the theory of what happens and use it for tuning. But it doesn't seem to a linear full spectrum fuel enrichment, like the potentiometer is.

That's the right ECU. The problem might be from something else. We could probably offer some advice if you added some details to the "does not run right".

What's the number on yours? Share. Here's a Nissan Service Bulletin that I found on the internet a while ago. Looks like they all used the same, except for 1975, and 77 and 78 AT models. NTB94-097 (Nissan ECU Guide).pdf

You probably have multiple wiring problems. The Maxi-Fuse comes from somebody's Maxi-Fuse upgrade which means somebody has been messing with the wiring. Could be as simple as two wires touching or one pinched to ground. I would take a good look at all of the Maxi-Fuse block work and fix all loose connections, make sure the wiring matches the factory diagram (or atlanticz's page), and do some work with a meter. You won't learn anything at all by burning another fuse.

The above, the third part about restarting, does not match a blown fuse. Fuses don't fix themselves when they cool down.

I looked in the How To Rebuild book and can't find any sign that there's a difference in the L24 and L28 blocks besides bore. He doesn't mention the different timing chain guides either. Nissan probably did some minor mold clean up when they went to the N42 L28 block but if zcarnut can use the L28 piece on his L24 blocks, the bolt holes must be the same. It's probably a like-for-like piece, just so people get the same as what they're replacing. I've never seen anyone notice that before though. A new mystery. p.s. I was joking on the Kameari kit. Unless you're planning for 13,000 RPM.

That is weird. The L28 kit costs more, but wouldn't have the fuel pump drive cam. And if the L28 guide is better, why even sell the weak L24 guide. Maybe people just like to see identical replacements parts in their kits, so MSA gave them that to stop the questions. http://www.thezstore.com/page/TZS/PROD/10-2050 http://www.thezstore.com/page/TZS/PROD/10-2051 Maybe they've been doing it for a while but MSA now has Kameari parts. Upgrade your cam control! For just a few dollars more. http://www.thezstore.com/page/TZS/PROD/10-5470

Actually, one remaining question is "should you replace those bushings with PU bushings?"

If you do find that the internals of your 76 distributor are rusted and gummed up, the ZX distributor is a good option also, because it uses a high energy ignition control module and coil (so you'd want a newer coil too, projects always grow...). 1976 still uses a low energy coil and ballast resistor. But if the guts are in good shape, it might be worth keeping. I marked up a picture to show another simple way to check the breaker plate. But, they are almost always rusty and need lubrication. They are super easy to take out and replace and you'd have to work to get it in backwards (no offense to those that have managed to do that). It will only install the right way or 180 off, no gear teeth to worry about. It will only go in 180 off if the tang and slot are worn, and you can't distinguish the big half moon from the small one.. Take the big screw out, it might be very tight, gently loosen the vacuum module, it might be very tight, and gently pry it out part way with a screwdriver. It might be very tight. The breaker plate with the pickup coils on it should rotate. But, if you pull too hard you might break the bearing holder under the plate and screw things up. So it's dangerous. Were it mine, I'd loosen that big screw while it's mounted in the engine, give the module a little twisting to break it free, then remove the distributor and take a good look. The breaker plate comes off easily also, and you can check the centrifugal weights. The other way to check operation though, is with a timing light. Connect intake vacuum directly to the module port and see what happens to timing. Edited - backward arrow.

The only part that matters on the reluctor is the very edge of each tooth. That's all the pickup coil sees. You can shine up the rest but it won't affect performance. I'd be leery of any aftermarket reluctor because the precision of the timing depends on the precision of the machining. I'd rather have a rusty factory reluctor than a new aftermarket reluctor. Another way to check the breaker plate vacuum advance is to just twist it with your hands. But eyeball the edges first for rust. If there's any at all, best to take it out and clean it up. The balls will get stuck and the bearing holder will break. Not good. A common problem on the EFI cars is a lean mixture from the ECU. Adding the potentiometer to the coolant temperature circuit will help. Here's a good link, many do it. It's reversible if it doesn't work. http://atlanticz.ca/zclub/techtips/tempsensorpot/index.html