Captain Obvious

Are the part numbers on all of the injectors the same? And as for the resistor/no resistor 9V vs 12V thing without getting too deep into theory... The injector contains a coil (an inductor) and the current through that inductor cannot be described simply by (V=IR). The current through an inductor has a function that is dependent on time. It looks like this: Which says "The current at a given time equals the maximum current minus an amount that gets smaller as time goes by." So when voltage is first applied to the inductor, no current will flow. But as time goes by, the current will eventually max out at a value of I=V/R where the "R" in that equation is a combination of the injectors internal resistance, the series dropping resistor next to the brake master cylinder, and the internal resistance of the power source which is supplying the current. When you are testing using a 9V battery, you have removed the dropping resistor from the circuit and if the battery were capable of supplying enough current, the injector would burn up. But thankfully the 9V battery has a lot of internal resistance and is not capable of supplying that much current. The injector current is limited by the fact that the little 9V battery just can't supply that much power. If you would be to connect the injector directly to your big 12V car battery for long enough, the injector current would be limited only by it's own resistance and it would likely draw enough current to burn itself open. Your 9V battery can't do that, but your car battery sure can.

I'm not a coatings guy, but I have a couple questions/comments: First, I probably misunderstood what you were talking about with mixing on a board and a catalyst above, but that 907 spot putty is a one part non-catalyzed solvent evaporation process only. If you were mixing that 907 with the cream or liquid catalyst (that you use with fiberglass or polyester filler), I have no idea what would happen. I can't imagine it would be anything good though. Second, I've been told that powder coating is a difficult surface to adhere to. Tough, hard, slick, non-reactive... All the things you don't want in an undercoat.

I'm away from home and have spotty internet access, so I can't go into much detail, but I'll do what I can. The device you are calling a "transistor?" is a coil or transformer of some sort. Hard to tell from the pics, but it looks like it only has two wires going to it, and if I remember correctly, the whole radio goes dead when it's not connected? If that's the case, it's probably what they call a "choke" and it's purpose is to filter out high frequencies on the power input line so the noise doesn't affect the electronics inside the chassis. If it is a choke on the incoming power, it exists to keep noise from the ignition coil from messing with the radio. Also the terminal block thingie looks to me to be a line of "feed thru capacitors" who are another means to filter signals. One feed thru for each wire entering or leaving the device. Can you take a pic of the other side of that block? Of course I'm looking on a tiny dark screen and am guessing... As for how stuff fits back in, my experience is that kind of equipment is so tightly packed that stuff only fits one way! Think Jenga or Tetris.

You would have had to peel me off that big bandsaw. Also, what's the olive drab green thing in the upper left background of this pic? Right behind the guy?

How funny is that... I've been doing the exact kind of work on the rear decking on my car right now too! I'm at the cardboard template stage and haven't started cutting MDF yet. I've got my rear cargo covers installed and am working on dropping the rear deck as much as I can to reclaim some of the space back there. That's beautiful work on your rear decking. it is my belief that the original stuff was mass produced with large gaps such that the panels would fit into any 77-78 without interference regardless of the other parts involved. If you're making a custom set, you can cut those tolerances way down.

I just couldn't bring myself to take my car out in that rain. I hid at home in the dry garage instead. I really wanted to take a good look at some of those second or third revision Miata seats that your bud had for sale there. I've considered putting a pair of those in the Z. I've got Fiero seats in there now and I find them extremely comfortable, but I've always wondered how Miata seats would do. Couldn't stand the weather.

Yeah, I'm unfortunately in the same boat. If it was going to be a little rain, or just a chance of rain for a short period of time, that would be different. But the current forecast looks pretty wet, and I don't want to subject my not rusty Z to all that water. I guess I'll keep tabs on the details, but at this point, it looks like I'm probably going to pass.

Not trying to take business away from anybody, but an ignition switch isn't something I would buy used. Datsun didn't use a relay to handle the current for the starter solenoid and this is what happens inside:

I believe there are options available for a replacement thermostatic valve, but it won't be a direct drop in. There are valves for other applications (not necessarily specifically automotive) out there if you want the function and are willing to deal with having to modify the system to adapt a different form factor. Here's a couple ideas: Heat activated trap http://www.thermomegatech.com/product/hat/ Hot water balancing valve: http://www.thermomegatech.com/product-categories/domestic-hot-water-balancing/ There has also been some past discussion at the Z car forums. Here, Zcar, and Hybrid. Search isn't the best at any of them, but if you've got the time...

I took a look through the pics I've taken in the past, and everything is micro instead of macro. In other words, I've got close-up pics or wiring harnesses and ignition coils, but nothing of the show field. I'm guessing maybe twenty first gens?

Great results. Glad you could come up with a solution to your issues. I wouldn't necessarily call the water flowing through the carbs a bad idea though. It speeds warm-up and improves performance in areas of the world that are not as hot as where you are. It also prevents icing which could occur even where you are. It's just clear that "too much of a good thing" can cause problems. If your valve isn't closing until 195-200, then that's too high. Test procedure on 74 FSM page ET-5 says is should be closing around 130F. In your climate, I suspect 130F occurs about thirty seconds after leaving your house. Point is, blocking it off completely isn't much of a change where you live!

There was already a thread started about it couple days ago: http://www.classiczcars.com/topic/55453-0064/

It got a bid at 50K, and get this.... Reserve not met!!! He's got a reserve on it ABOVE 50K. It's beautiful, and I'd love to have it. But for that money? "All original?" In addition to what is in the ad and what has been mentioned above already: H4 headlights. Hood misaligned and standing proud at the front. Front tip of the hood looks rounded like it was pushed in and subsequently fixed. Crack in the right sugar scoop. Green paint overspray on the muffler? Speakers in the doors. Some weird mount (cell phone?) attached to dash. Poor fitting seat covers. Parking brake boot missing. Overspray on front strut tower nuts. Green overspray on floor pans under car. And what's the red spot poking out from underneath the VIN tag? That to me looks like the car used to be orange, but I don't see any signs of that anywhere else. Like I said, it's beautiful, and I hope for all our sakes he gets what he's asking, but geez!! And for that low of a VIN, I'd want history and mileage documentation.

I'm planning to attend. Been there the past few years. A little further for you than for me. If you do decide to go, get in touch beforehand so we can be sure to find each other at the show.

Excellent. So make sure you keep us posted on the original problem and what the behavior is after you figure out what you're going to do about that thermostatic valve. This would be the first well documented case I've been close to.

Sounds like I've brought out the inner Bubba in a bunch of you guys? I'm just going to cover my ears and pretend I don't hear any of this!

So something else you mentioned before... You said that the water passage going to the balance tube was clogged. That passage to the balance tube is primarily to cool the EGR valve and the balance tube where the EGR mounts. If your EGR system is functional, it get's extra hot there and I've seen reports of the passageways burning through due to the heat. Point is... If your EGR is working, you might want to make sure that line flows. Also, it's a good idea to keep some small amount of coolant flow into the thermostat housing, even when the engine is cool. Thoughts being, you don't want a stagnant pool over by the thermostat. In the stock configuration, you've got three ways for water to flow through the intake tract: 1) through the carbs, 2) through the balance tube, 3) through the intake manifolds. I don't remember if all of those three paths are regulated by the thermostatic valve, but if you do block off that valve, it might be a good idea to make sure at least on of those three paths still passes water somehow.

Excellent. Sounds like my skepticism was unfounded and I hope that you have identified the root cause. There has been chatter about that thermostatic valve in the past, but I'm not aware of a cheap viable alternative. I hope yours cleans up with the dunking, and if not, it sounds like you're going to have to just remove the carb water flow like so many 260 owners before you. Wow... Down to the 60's. Everyone wearing winter coats?

Haha! There is much disdain in machinist circles for those who use their drill press as an arbor press. Similar to the amount reserved for the people who use their calipers as adjustable wrenches.

The antenna trim screw probably adjusts the value of a small variable inductor of capacitor. I'm not sure if I'm understanding your findings or not, but there should be no visible physical mechanical change as you rotate the screw. The other problem sounds simply like a broken connection. Is it something that you can't just resolder into place? Can you take some pics of the area of concern? And as for off the shelf or not... Even if it was off the shelf in 1970, it's not off the shelf anymore. Things have changed.

That would be a fifteen second job on my hydraulic press. Thirty seconds if I had to adjust my table position for the length of the shaft first. Nyeah, nyeah!

Haha! Getting confident is just an invitation to let Murphy refresh you on his laws. And the cockier you get, the more expensive he gets. Patcon, It's still gets "cold" sometimes in FL. Heck... I could say the same thing about where you are compared to PA.

I like it! DId you make that up? "Anchoritis" kinda flows too.

Interesting findings and I hope it's that simple, but call me skeptical. Wouldn't be the first time someone thought they had a problem licked only for it to return again in the future. To test your theory, get the car back to stock. Fuel rail back where it belongs, water passages as they were a couple days ago, etc. And then recreate your shake test. Shake the car as you did before at hot idle, and verify that fuel glurps out of the bowl vent tube like it did before. Has to be repeatable. Then once you are positive that you have the car in the state where the fuel overflow will occur, shut the motor off, give it ten seconds or so for pressures in the fuel lines to stabilize and then repeat the shake test. If the theory about flash boiling the fuel by contact with the coolant passage inside the carb is correct, you will get a glurp of fuel out the vent tube even with the engine not running. But if you do NOT get a glurp with the engine off, then you're chasing a red herring. Reason being, if the overflow is caused by flash boiling fuel that is coming in contact with that internal heated passage, it shouldn't matter whether the car is running or not. Ten seconds after you shut off the engine, that passage is still at the same temperature, and the fuel level in the bowl is still at the same level. Results shouldn't matter whether the engine is running or not. Does that make sense?

Note that I've not actually tried that "inflate the bag" test technique. I was just thinking that if the float chamber is getting supplied with an overabundance of vapor, then that vapor needs to go somewhere. My first thought was trying to inflate a balloon, but I don't know how much pressure it takes to blow up a balloon. So I figured that a completely deflated plastic bag applied to the vent would require less pressure to inflate than a balloon. In fact, I would guess that a plastic baggie would take darn near zero pressure to inflate until it was plump. But by then, you'd already have your answer. I'm interested in getting to the root of the problems you're having because the reports of heat related fuel problems with the flat top carbs run far and wide, but I've never been convinced that it's actually a carb problem. I've never personally had any heat related issues with the flat tops, and this is the first instance where "replace" is second choice behind "fix". Most people just give up and replace.