Captain Obvious

I'm not clear what's happening... Is the knob stuck and won't turn, or is the knob turning and turning but not coming off the shaft? Heh... Yeah, there's a plan!

OK. So now I've heard people talking about problems caused by it cooling too soon. I can shut my engine off for 5, 10, 15, or 30 minutes and it doesn't have a high idle when I restart. Hmmm... Maybe yours is working fine and mine is operating oddly? Maybe it's the way I have my AAR adjusted? When you restart after a few minutes stop and you get the high idle, you can verify if it's the AAR causing the high idle by pinching off the large tube coming off the AAR. Might be hard as a rock when cold, but you might be able to pinch it shut when the engine is warm. If the AAR is open, the idle will drop when you pinch that hose. If it doesn't change, then your issue is elsewhere.

I'm not an expert on the device, but I've not heard people talking about problems caused by it cooling too soon. I guess this would be more of a problem in cold climates. I do remember someone messing with a heat wrap for some reason though... Blue maybe? He's in Canada and would certainly have more potential to need a wrap than people in a warmer area.

Yeah, I suggested a "mistake" above, and what I actually meant was a "seemingly illogical choice to the uninformed". I'm thinking that it was for some ease of manufacturability criteria like what you suggested... They didn't need it for the current carrying ability, but it saved them from having to stock yet another style of wire on the floor? Maybe it saved them from having to stock a different style of connector? I've been poking around the headlight wiring lately and I saw that R/W wire. It's been bugging me since I saw it. I couldn't come up with any electrical reason for the larger gauge choice at that location, and I was wondering if I was simply missing something! You've got an earlier year, right? Did they do the same thing on the earlier ones? Is that R/W larger than the other two?

Thanks for the thoughts, and what you are saying makes complete sense, but that's not what we have here. I'm talking about a point before the two smaller currents join to make a bigger one. At the point I'm talking about, the current for each headlight is independent. The return currents have not yet been joined. The wires I'm talking about go to one and only headlight. Here's a pic of the right side. I can guarantee that every electron coming away from the right side headlight on the thicker red/wht got to right side headlight on the thinner solid red: The three headlight wires come out of the harness, go through the round connector and pass through the inder fender wall on thier way to the headlight bucket for the right side ONLY. (The left side has it's own three wires that come out of the harness on that side, pass through a similar connector and disappear through the fender wall on that side to feed the left side ONLY.) After the two sides join it would make perfect sense to up the gauge, but at the point where I'm talking about every electron coming back on the thicker return wire was supplied through the thinner supply. I'm thinking that it was a mistake in the design dept...?

Yeah, that makes sense at first blush, but think about it... The same current coming OUT of the high beam on the thicker wire had to be supplied INTO the bulb through the thinner wire. I'm talking about after they have split for each side. This is right at the connector leading through the fender walls and into the buckets. I'll snap some pics tomorrow if I get a chance. It wasn't intended to be an easy question... :classic:

If I were doing what you're doing, I would skip the tape completely and just mask a band of high temp red paint on there. Brush a couple thick coats on and it will even appear to have the raised thickness area. Nowhere near my area of experience, but is there some other reason that tape would be better than paint? [snicker!] :classic:

Here's a more much simpler way to describe the issue: There are three wires coming off each headlight. At any instant, two of those three wires have to carry the exact same current... One in, and one out. What possible reason would there be use a thicker gauge on one and only one of them?

Thanks for the thoughts guys, but I don't think it's either of those. Let me rephrase with just a little more detail... Way up by the headlights just behind the radiator mounting plate, there are three wires leading to each headlight: On the right side, the three wires are a) red/white (red with a white stripe), red/black (red with a black stripe), and c) solid red with no stripe. On the left side, the three wires are a) red/white (red with a white stripe), red/black (red with a black stripe), and c) red/yellow (red with a yellow stripe). On both sides, the red/white (red with a white stripe) is a thicker gauge than the other two. Why? Why? Why? SteveJ, I believe you're thinking of the white/red (white with a red stripe) coming from the fusible link to the combo switch? That one comes out switched out of the combo switch as solid red and goes to the two fuses in the fusebox. Coming out of the fusebox are the hot wires for each side. Right side gets fused solid red while the left side gets fused red/yellow. I'm not talking about any of that... I'm way up by the headlights talking about the red/white, not white/red.

McMaster has a few possibilities? 75895A26 - Super-Thin Surface-Protection Tape -Good to 300F 7800A11 - Super Wear-Resistant Slippery Tape - Good to 500F

Glad you got yours figured out! Now that you've done that, I've got a simple question about my headlight wiring and your thread title is so perfect that starting another thread would be a mistake. (I've been wanting to ask, but didn't want to distract anyone from you...). I've got a 77 and I want to know why the red/white wire leading to the headlights is a thicker gauge than the other two headlight wires.

Heh. I suspect there are very few 73's or 74's that still have all the emissions stuff still intact. Congrats again on the new purchase! If that body is as good as it looks, then you got a real nice one there!

Yup. I bet when your cap melted, your shaft shifted a little. I'm trying to come up with some sort of test to check for alignment quality, but I'm not coming up with anything simple that wouldn't require special fixturing. You can't roll the stalks on a table and look for wobble because the thumbscrews aren't round... How about pulling one of your domes off the top, screwing in the stalks one at a time, and then flipping the domes open end up and measuring the distance between the jiggly bits and the inside of the domes at a couple different locations? It's crude, but if it might be accurate enough to see a difference between the good damper and the questionable one. Of course, all of that is academic... You need a new damper stalk. I don't have anything for round tops, but I've got spares from flat tops... If you do the legwork to figure out if they're the same or not, I'd be happy to send you one if they are the same.

The projected tips don't stick down that far... I can't imagine there is any significant increase in CR. Could be wrong, but I would have to see the numbers to believe it. Cost? Who knows? Don't know if it has always been the case, but today they all cost the same. I'm at a loss... The most perplexing additional info is Zed Head bringing to light that they went back the projected tip with the P79/F54 combo in 1980. What made them want to pull that spark back towards the hole from 1975 through 1979?

Warning... Thread detour: So you took an early steering column completely apart? I've got one in that exact same state sitting on the bench right now... Did you take the bearings out, or did you stop where you took that pic?

It appears that Datsun switched plugs from the projected tip BP6ES (where the "P" means "Projected Tip") to the standard non-projected tipped B6ES (no "P") in 75? But what's interesting is that the small amount of armchair research I've done seems to indicate that the farther down into the cylinder you get the spark, the better the burn, and projected tips help in that way. Anyone know WHY they switched to the standard non-projected tips? Any reason I should not use the older projected tip BP6ES plugs in my 77? Here's why I ask... I've got projected tips in there now from my previous owner and they looked perfectly normal to me (after looking at 260 plugs for so long). They aren't hitting anything. They aren't burning up or showing any signs of overheating. They appear to be just fine and are loving life. So... If I've got the room for them, and the current projected tips aren't indicating any problems whatsoever, then is there really any reason I should switch back to the recommended non-projected tips? Maybe I should take advantage of the potentially better burn and stay with the projected tips even though it's not what Datsun recommends? What's the downside?

And.... I've been digressing into the comparison of the 72 and 73 and haven't even yet commented on your car in general... Congrats! It's a beauty!!

That makes much more sense for the new purchase to be a 72. And with that in mind, it looks pretty original to me too. There has already been some simplifying of the intake side already done though... When supplied new, you had: A PCV system. A throttle opener system. An evaporative emissions control system (flow guide operated). An air injection system (the air pump system). An anti-backfire valve system. An intake manifold and carb heating system. Of those, it looks like everything is intact with the exception of most of the air pump system and your anti-backfire valve (which is incorporated into the air pump plumbing). The only thing remaining from the air pump system is the air galley leading into your exhaust manifold and the check valve (that goes nowhere stub of tube pointing at your front carb). All of this may sound complicated, but just wait... Here's what the 73 looked like new. Complete with flat tops in all thier glory : In addition to all the stuff you got in 72, you also get an EGR system, a thermostatic air cleaner, an more complicated throttle opener system, a much more complicated carb and intake manifold heating system, separate idle circuit plumbing, etc! So if you're comparing your current 72 to your prior 73 and the 73 was simpler, then there must have been some serious work done to that 73!

A stock 73 is way more complicated and cluttered than what you have here. If this most recent purchase is a 73, then someone has made a lot of changes to the carbs and emissions controls. I took a look back through the thread, and I'm not sure you ever mentioned what year this car is... What is it?

I don't know if you would be able to actually smell a difference if your air pump is working or not. I do know that there are plenty of other reasons for a 260 to have a horrible exhaust smell. But as a data point... From my experience, a well tuned and proper operating 260 doesn't have a horrible exhaust smell, even without an air pump installed. As for the EGR tube, I'm not sure what you're talking about. The only tubes involved in the EGR that are soft enough to pinch are on the control side and pinching any of them could only result in the EGR becoming disabled (which usually improves performance, not degrades it). Spiders and chipmunks are better than floors and rocker panels with rust holes in them. To be honest? Dude, it's October. And you're in Connecticut. And this is your only car? You gotta do something quick.

Sorry TomoHawk, forgot to get back to you about how to control such devices. If I were to go to a solenoid valve, I would try to install a temperature switch into the thermostat housing. So I was thinking about it a little more, and what would be the real ticket would be to use an analog temp sensor (like the one that's already there), and use that analog sensor signal to control an air valve that is more complex than a simple ON-OFF solenoid valve. The air valve should be open when the sensor indicates cold, and closed when the sensor indicates warm, and partway when in-between. Kinda sounds like an idle air control valve, doesn't it? :bulb: Haha! Now vehicles have such devices incorporated directly into the throttle bodies!

Wait a minute... You're saying that this car is more complicated than a 73 you used to own? That doesn't make sense... The 73's had the first year of the flat-tops and all the associated complexity of the EGR and thermostatic air cleaner and CARB can, and and, and... This car you've pictured should be way simpler!

Thanks for that link. I remember breezing through that page a while ago, but I didn't read it closely enough to catch that line about a manual valve. I wouldn't be surprised of one of the older fuel injected Alfas used something like that. My old Alfa had a twist knob on the dash that would actually hold the throttle linkage down. It was a fine thread and you could turn it to raise the idle. Heck you could even turn it fifty times and use it as "cruise control" on the highway. :stupid: It was all mechanical and acted on the original carb linkage. In other words, the end result was the same, but they didn't put in a separate valve for the task. Instead of including a path around the throttle plate, they simply opened the throttle plate a little. Hmmm... All you need is a cable controlled valve that bypasses the throttle plate. I've got a couple leftover water control valves after my heater valve relocation project... :bulb: :laugh:

The 260 system is complicated. There are lots of tubes and wires and hoses and valves. It was the culmination of Datsun's efforts to provide good cold driveability, good fuel economy, and good performance all while meeting ever tightening emissions standards. That complexity works great when everything is perfect, but once it starts to fall off that razor's edge of performance, finding the problem(s) can be difficult. And that's where you are. You've got a forty year old car with unknown history. It's got dry rotted brittle tubing, solenoids that are probably frozen in place, sensors that might not work, valves that should be shut that are leaking, valves that should be open that are clogged, vacuum leaks, a dirty fuel tank, carbs that probably need a rebuild or more, and a questionable ignition system. Simply... The 260Z is not a car for the feint of heart. If you want it, you gotta want it bad. You have to be willing and capable enough to dive in yourself and learn how it works. Download a copy of the factory service manual and study it. Learn the terminology and where the components are. You've got to be able to point to something and call it by the same name that the manual calls it and have at least a basic understanding of what it's supposed to do. Without that level of knowledge and standardization of language, remote troubleshooting doesn't work. I know the 260 system pretty well, but I'm not close to you. If you bring the car to me and leave it with me for a month along with a stack of $100's, I'll fix it. If that doesn't work for you, then you need to find someone else closer to you, or learn to do it yourself. I'll do what I can from a distance, but diagnosing problems based on vague description is very difficult, especially when you've got so many places that could be causing problems. I'm not trying to scare you off. In fact, it's the opposite. I'm encouraging you to embrace ownership. Unless you're willing to pay for someone else to do it for you, you're going to have to learn a lot about the system yourself. My bottom line suggestion would be to buy something else to use as your daily and work on the Z in your heated garage in the meantime. If you drive the Z through the winter in CT, there isn't going to be much left.

Right you are, and good to bring that up so other people don't think that my car is "normal". What's missing on mine is the "thermal vacuum valve", and in addition to providing a "hot plate" for the AAR, it also enables/disables the EGR system based on water temperature. Mine was removed by a previous owner. I'm probably going to put mine back on, but it's lower priority at this point. I was worried that without the heat from the TVV that my AAR would never get hot enough to completely close, but that hasn't been the case. I've got my AAR adjusted to only provide a very small amount of additional air when cold, and it seems to generate enough heat with the internal heating coil to close even with the missing heat from the TVV. Of course, I haven't driven the car in any really cold months though. I might miss that TVV heat more in Feb than Oct. As for the issue of being always on, I (like you) am a little surprised that the AAR heating coils don't burn out more frequently. I believe the reason they don't burn often is that while the current is always present, it's pretty small. My AAR coil is around 60 Ohms, so at 13.6 V it draws less than 250 milliamps. And one more... I (also like you) thought about the possibility of ditching the AAR and using a solenoid valve(s) to control the auxiliary cold air around the throttle plate instead. My first stumbling block with this is that the solenoid valves are ON-OFF as opposed to the gradual "analog" closing of the AAR. I guess you could use a couple of solenoid valves in parallel and close them at different temperatures to simulate analog control, but that's more switches and more complexity. Not sure if it's worth it.