Captain Obvious

On the cars without factory air, that vacuum valve is not present. In fact none of the vacuum valves are present at all. The non-A/C cars (like my 77) have all manual cable controls and do not use vacuum at all. And although you didn't ask, that rarely ever stops me... Yes, the reason they put that vacuum shut off valve in place is to shut off all the water flow to the core whenever the A/C is on, but it's a little more complicated than that... The temperature control slider lever not only controls the temp for the heater, but it also controls the temp for the A/C by cycling the compressor. So if you want to be able to use that same control lever for both functions, you have to cut off the water when the A/C is on. Unfortunately the desired temperature ranges for the two functions are so wildly different that they couldn't use the same simple slider to do both controls without completely disabling the function that wasn't being used. Did I say that right? Does that even make sense?

Mike, Full disclosure, I did not actually install that version in a car, but I did place the blower assembly and connecting duct into place to verify that there was no interference. So, while I cannot guarantee with absolute certainty that I did not overlook something, I have a very high degree of confidence that it fits fine. Here's some pics of that version with the blower and duct in place. Top view: View from the firewall looking backwards: View from the interior looking towards the engine:

Actually... Inside the ECU, the pin connected to the AAR is just hard shorted to ground. So they have the connection AVAILABLE to the ECU if they ever wanted to use the ECU to control the AAR, but they do not use it like that. It's just shorted to ground inside the ECU. So other than the fact that the ECU has to be plugged into the connector, there's no real interaction between the AAR and the ECU. Anytime the engine is cranking or running, the AAR will be internally heating. The reason they also externally heat it with the coolant plate underneath is that the internal electrical heating may not be enough warmth to close the AAR on a very cold day. Like when the air flowing through it is also very cold.

I'm not sure if there was a misunderstanding or not, but just to be clear... The TVV does not heat the AAR.. Hot coolant heats the plate under the AAR. The same plate into which the TVV is installed. So the COOLANT heats both the AAR and TVV and the Issue being if you remove that entire plate as part of a "TVV delete" then you will lose your external AAR heating as well. Now the AAR is also INTERNALLY heated, so depending on how cold it is where you live, the internal heating may be enough and you may not miss the external heat source at all. That is what happened in my case, but in Canada, it might be a different story.

If you remove the EGR actuator at the end of the system, then all the rest of the stuff in between becomes teats on a boar. The ONLY thing the TVV and BPT does is modulate the vacuum to the EGR actuator. So if there isn't any EGR actuator, then there's no need to modulate the vacuum to it and both the TVV and BPT devices become useless. You don't have to remove them, but there's no reason not to. Just plug the vacuum source on the throttle body, and if you remove the TVV, you'll have to plug the coolant hole where it used to be. Or you could leave the TVV in place just to keep the coolant from running out, but don't connect any vacuum lines to it. Now, about the heating plate under the AAR... It also serves to heat the AAR itself, so it does serve a second function other than the EGR. But my PO had removed my heating plate, and I never really noticed any problems. Being in a cooler climate, you might find that your AAR will open up some and raise your idle even when you don't want it to do so, but where I am I did not have that problem.

Nice six-pack. The best flat top pair to put back on the car might not be the originals. There were a number of revisions of the flat tops between 73 and 74, and if you have different versions, I would absolutely use the later design. And since a lot of them were upgraded at the dealers in those years due to customer complaints I would contend that the later design should still be considered "stock" even on an early 73 car. Changes described in the 73/74 carb modifications documents and TSBs. (Ref TS73-38 and TS73-81) So I'm no carb expert or stock car show judge, but I would not ding a 73 in a stock class even if it had the later version of the flat tops on it. YMMV

It's SWOMBO's fault... She decided she needed a fun car for herself and is taking up the other garage bay. I used to have full run of the garage, but not anymore. There are two bays and her stupid Boxster taking up half of it. LOL.

Cool. My point is there would be no shame whatsoever to take five steps backwards before you take ten forward. Even if it means un-doing a lot of work that someone else has done before you. Especially if the backward steps make the future forward steps way easier. I'm sure you'll get there eventually on either path, but I'm just thinking "easy".

You brought her.

And I've never told you my opinion on the whole build and stuff.... If it were me, I would want to get it running and on the road. And with that in mind, I would probably seriously consider putting a stock 280Z motor back in and shelve the whole turbo thing for the time being. You're going to have 10,000 problems and issues and things that you're going to have to spend time on. And a number of them you won't even know about until you get a bunch of miles under your belt. You haven't talked about your background, but I suspect you are tech savvy. But even with that, the documentation won't line up. The wiring diagrams won't line up. You'll be going to different manuals for different parts of specs. Your wife will hate it a whole lot less if it's running and you have in good enough condition for you to drive to work. Then after that, I would start thinking about serious upgrades and changing things. Maybe it's just me, but someone else's half finished technical project isn't a good starting point on something like this. There's probably some kid on craigslist close to you who wants two hundred bucks for the just yanked perfectly good running L28 he just pulled because he's going to drop in an RB28 or something. He'll never finish his project, but you could pickup his takeout motor for cheap and get some miles behind you. IMHO.

Yup, that's Gary's Z. The wheels spun under their own power for the first time in five years yesterday. Up and down his country road a half mile while still missing a lot of the body panels. And you're right... There are changes to those carbs that you can't see in the photo. You and I have discussed most (but not all) of them. Clock's-a-tickin, but we're still hoping he'll have his car at Zcon. Power to the Flat Tops! Haha! I'll stop the thread jack! All the flat top talk got me worked up.

Yeah, that's completely conceivable. Everything up top all baked and stuff while the stuff in the shade should look a lot better. Good luck with it. If I had more room, I'd have more Z's. (And a whole lot of other stuff.)

LOL. And I'm just kidding of course. It's only paint. You surely got bigger fish to fry, and will for quite some time. Now if it was Z-Patriots or Z-Cowgirls, then I might have to call in a spray can favor at your end of the country.

@Zup How many mods can you spot? There'll be a short quiz at Zcon.

BTW, on a semi related note... This is what I was working on today. Maiden voyage after paint up the street and back. Runs great. Haven't really opened it up yet, but so far, I'm very happy with the results!

Wow. What a PITA. Glad you got it off. Now all you have to do is get those rusty studs out of the intake manifold without snapping them off.

Haha! Well if you can prove provenance to a Seahawks player, then fine. You could keep it. But if not.... I mean, it's your car and all, but it makes my eyes clamp shut by reflex. I can't help it.

Cool projects. Clearly you'll be a busy guy! Couple of observations, comments, etc. First, about the fuel injectors... I'm assuming that black painted injector is one of the rebuilt units? If so, I would take the paint off the nose. I don't know what kind of paint that is, but I question it's longevity in the very hot, fuel spraying environment while in use. And I don't think I want that paint dissolved or flaked off inside the engine. I'd rather have it come off first before I put the injector into service. I also wouldn't want paint where the vacuum seal is. I think I would strip the paint off as far back as to include the seal surface as well. And second, I'm hard pressed to be convinced that is really just a 30K mile 77... Are you sure it's not 130K? I mean, it doesn't really matter since I'm not buying or selling, but if that's just 30K miles, it's certainly a HARD 30K.

Elvis needs boats! Elvis needs boats! Elvis, Elvis, Elvis, Elvis, Elvis, Elvis, Elvis needs boats!

It's a 78, right? Looks like a great project. And you're not allowed to post any more side view pics until you have removed that Z HAWK decal/paint thing. That's just got to go! And quick!

Nice condition base to start from. Good to see that it still has the original intake manifold and balance tube. You just need to find someone who knows flat tops. And shift knobs.

LOL. I don't think there was any disrespect. Here's my translation: "You know that for the 78 280Z, Datsun went to a three prong oil pressure sender that has a switch built in. And those switches are still available aftermarket for cheap. So with that in mind, why are you messing around with adapting Fiero parts (which may or may not have the correct plumbing thread) when you could just buy the sender unit for a 78 that already has the switch AND has the correct threads?" I believe that's what SteveJ and ZedHead are alluding to.

Seconding the above. Going to a larger sized pin should be fine. Mine squeaks too, but it's further down on my priority list. Nice! So is it velvety smooth? Did it work out as intended?

Thanks Jim. I understand much of this isn't a huge help to you if you are still using the original temp control valve. I will spend a little time exploring options that do not require moving the valve into the engine compartment and see what I can come up with.

I'm sure you could find a cool low value resistor at Sky-Junk to use as a shunt. Or an old surplus military grade panel mount ammeter with a 100A scale. Another option would be to use two of those cheapie Harbor Freight VOMs in parallel on the 10A scale. Based on the assumption that the internal shunts of the two meters are close enough to the same value, this should work and two of them in parallel should share the current. I've done it with good success. But the bottom line is there's no way you should be generating enough heat there to melt your fuse box lid. Is the melty at one end of the fuse, or over the whole thing?