Captain Obvious

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.

Sweet. Looking forward to it. So, the gauge I have works fine, and I know that because I used it for a while in my car until I swapped out my entire dash for one with "fewer" cracks. Now all I have to do is keep my mitts off it until you get here. Problem is you've got me all curious now!! So to quell my curiosity, I did a few minutes of armchair research and I believe the bi-metallic strip with the contacts (not the one that moves the needle, but the other one) is a temperature compensation device in addition to a voltage regulator. It pulse width modulates the current through the other strip in response to changes in ambient temperature and system voltage. http://home.roadrunner.com/~john.strenk/Gauge%20web%20page/WebPageGauges1.htm Remember though, I still haven't been inside one myself. And I promise to TRY to keep it that way until you get here!

Don't get me wrong. I'm not saying my 77 doesn't have the rollers... I'm just saying that I don't remember seeing them. I had my driver's side door panel off a little while ago and I just put it back on. I wasn't in there for window stuff so I wasn't specifically looking into it. I'm gonna pull the pass side next, and I'll definitely pay a little more attention while I'm in there on that side.

And another suggestion... I've got a spare 77 gauge that works fine, and you're welcome to have it if you want. Don't know if it's the same as what you're working on, but if it would help, just let me know!

The small hoses are 1/4 and 5/16. Between those two sizes you'll have all of the small stuff covered. The bigger stuff (the braided stuff) is more difficult. The hose on the top going to the valve cover is straight enough that you can easily find a replacement at the parts store. The problem is the braided stuff from the air cleaner to the carbs and between the two carbs. Of those, the one between the two carbs is the highest priority since it's at the highest vacuum and will such the most air if it has a leak. I'm thinking that you should visit that guy who knows the SU's.

I've never looked inside the gauges, so I'm shooting from the hip... Put a small capacitor across the arcing contacts to act as a snubber to prevent future arcing and use some gold leaf from the craft store burnished onto the contacts to provide a better contact?

You can add round top carb swap to your list of updates/replacements. A previous owner removed the original flat-top carbs in favor of the older round tops, swapped the original EGR balance tube for one from a previous year, and replaced all the carb linkages accordingly.

Are the 77/78 doors supposed to have that roller? I don't think I've got one (in my 77).

Mine was giving me trouble, so I carefully opened it up to clean it out and adjust. Then I drilled and tapped the casing for three small screws to hold the clamshell back together. Now I can disassemble and reassemble at will. Not supposed to come apart? Mine is! :laugh: Sorry for the crappy pics, but I didn't take it off the car just for a photo shoot. Two screws on top: And one on the bottom:

I wouldn't worry much about some oil in the valve cover hose. It's part of the PCV system and it's gonna happen. However, with that in mind, you should add checking/replacing your PCV valve to the maintenance suggestions provided earlier. Speaking of which... How much have you done with the car? Looked into any of the stuff mentioned earlier?

Yeah, I'm with E. I figure they felt they didn't need to show the tenths since the trip-O includes that. Just seemed funny to me that it was in there at all! Go through all that effort just to cover it up? The tenths digit does increment the 1's digit, and the assy (as designed) would not work without the tenths. Makes me think there were other vehicles that used the same assy that did show it. Something without a trip-O maybe? When I opened that thing up and saw six digits, my first thought was that there was a hidden 100K digit in there. And that would have been more than trivia. That would have been big news!! No more guessing how many times it rolled over! You know... With some modifications to the mounting tabs to make them a little wider, I bet I could add a 100K's digit to that thing... :bulb:

Not sure if this is common knowledge or not, but I learned something neat about the odometer today. You see five digits when you look at the odometer, but there are actually six digits available. There is a "tenths" digit on the odometer that is screened by the hole in the speedo face. Here's the front. There are five digits: And here's the guts. There are six digits, and the extra one is tenths: Who knew!?!