Captain Obvious

Are you using VR pickups or Hall Effect? You probably already mentioned it, but I don't remember.

Couple days ago I picked up a spare fuel sending unit to mess around with. First thing I did was checked the thermistor, and it's open circuit. So unfortunately no help there with analyzing a working one, but at least I get to see the thing with my own two eyes. So since the thermistor was already dead, I figured no harm in starting the autopsy. Desoldered the end lead: And pulled (what's left of) the thermistor out of the can. The thermistor nugget itself is completely vaporized. Just like what you guys found, all that was left was the two leads: I still contend that there is nothing interesting inside the black plastic end plug. Here's some shots of the two ends: A And for confirmation, I took it apart. It's just a brass ferrule with flared over ends so it stays in place inside the black plastic cap. And then they use that brass tube as a connection point to solder the flexible wire to one of the thermistor leads. Looks like this. They just bent the ends of the two wires into "U" shapes and hooked them together and then soldered the whole thing together: Here's the hollow brass tube after the solder has been removed: So there's no mystery hidden inside that plastic cap. It's just transition from yellow lead wire to the thermistor lead. @Dave WM If you're going to do another thermistor swap, you don't have to splice the wire to the old stub. You can just solder it into the ferrule.

What are the anomalous regions at the beginning and end of the run? Cranking at the beginning and struggling to run at the end?

Very nice! Thanks for the pics. That tester is very cool. Hope you can actually get it to work! Looking at the back of the board, I don't see anything that looks like a microprocessor. I I would have expected it to be computer based, but unless they used something small (unlikely during that time), it doesn't appear so. That thing must've cost thousands when it was new.

Lots of engines use the rail to hold the injectors in place, but all the parts used need to be designed to be used that way. The holes in the manifold need to be sized correctly for the O-ring on the nose. The holes in the fuel rail need to be sized correctly for the O-ring on the tail. And the distance between the manifold and the fuel rail needs to be correct. If those three things are achieved, there's nothing wrong with using the fuel rail to hold the injectors in place. Of course... The current engine does none of these. Boring the manifold out to accept the Green Giants, is just one necessary step.

Site, I was thinking of you earlier today when I saw the map. Hold on tight and be ready to get to higher ground!!

Yeah, I don't see how the disparaging comments about rotaries would cause this much of an issue. So I have no idea what I'm looking at with that graph. I mean, I can read the legend in the lower left, but I don't know what "normal" looks like. What's the horizontal time scale on that screen capture? It was running for minutes, seconds, a second? What's Haltech's response to this whole thing?

Wait! Don't cut the stub off! First thing to try would be penetrating oil, some heat, and grabbing that stub with a pair of pliers. If you cut it off, you'll lose that opportunity. Wiggle it back and forth. If you can get it to move at all, you're pretty much home free. And you've got another advantage in that it's not a blind hole. You have access to both side. Is there any bolt length sticking out the other side? And what is the base piece made out of? Is it steel or aluminum?

Man that's some bad karma right there. Did one of your ancestors pisss off one of Edison's or Tesla's ancestors or something?

We've got the hazy milky sunlight here at the eastern end of PA. I hope for the best for everyone dealing with the fires. No fun at all.

Thanks for the tool info. Some guys are artists with the angle grinder, but I'm not one of them. I'm worried that I'll slip into the strut tube. Maybe I'll try it on the band saw first and see how slow that goes. If that's excruciatingly slow, I guess I'll try the grinder.

I'm not sure the desired question is being answered... @texasz, Has your question been answered, or is the question a more general one: "Why do aftermarket parts cost so much less than genuine OEM dealer parts? Are the dealer parts really that much better to deserve such a premium price?"

I recently stripped down a pair of strut tubes and I took this pic down the tube. With the right reflected light, you can get a decent look down there. Enough to see the center portion convex outward and the weld bead around the perimeter of the dome: So any idea how much interference you have? Is it something that you could "workaround" by chamfering the bottom corner of the strut body? Take a little material off the OD at the bottom? Just a little? Maybe? Without creating a weak spot and blowing out the strut on rapid compression?

Haha!! Just like on the playground back in.... Wait, it's been so long that I don't remember how far back it was. So how was the event??? I'm so sorry I had to miss this and I'm looking forward to living vicariously through others!

@grannyknot, What tool did you use to cut your perches loose on your 510? When I cut the perches off the stubs I got from @wheee!, I did it on the lathe by boring the inside out until the perches fell off. Can't do that with the bodies I want to put on the car. I had originally planned to just go completely postal with the grinder and cut the perches off my tubes in pieces (since I didn't need to salvage them). But your removal method looked gentle enough that you could reuse the perches (which I assume was your plan).

So I found front suspension parts on craigslist and went on a safari to grab them. Nice guy, reasonable prices, close enough to drive to for heavy stuff. I'm very happy with how the whole thing turned out. Front suspension loaded in the back of the Family Truckster: Got it home and stripped everything down. Here's the strut bodies and the Tokico's that came out: So that's where I am right now. Had to resort to the pipe wrench to get the gland nuts off, but other than that, everything went swimmingly.

Why did you switch to Panasports? I've always liked the K1's. Something about them you didn't like, or just get tired of them?

I think the plan of leaving the manifolds and balance tube is a good one. If everything works out well you can always swap out the balance tube later if you get tired of looking at the EGR parts. As for the hard lines, some of them are water and some of them are exhaust. When/If you're going to switch over to a 70-72 balance tube, just cap all the water and exhaust ports off. If there's something specific you're concerned about, post a pic and we can talk about it. And it sounds like you're fine with the linkages. I think they only made two lengths (longer for the round tops and a shorter version for the flat tops), so if you got two different lengths from the guy you bought everything from, it sounds like you've got what you need there.

Haha!! That was my exact thought as well! Great call!

What? It wasn't obvious? Kidding aside, glad to help. Yeah, they took stuff out of the manuals over the years, and sometimes they added stuff. But it seems more removal of detail than added. (And I didn't look at the 78 manual (I stopped at 77), but you better believe I will now!!)) Hahaha!! Edit - It's not in the 78 manual. No surprise there.

Glad to help and good luck with the project. We haven't talked about balance tubes at all, but the bottom line is you can use any of them, including the one already on the car. The only "down side" to that one is the complexity and for that reason many people doing the round top conversion replace them with something simpler. And one tricky bit that you haven't hit yet will be the throttle linkage... The piece between the flat tops is shorter than the one used between the round tops. So for that reason, when you replace the flats with rounds, you'll find that center linkage piece to be a little bit too short. So keep your eyes open for some round top linkage pieces.

It's just a restrictor. As mentioned above, the check valve a different device. A little history... 1974 is the first year for the carbon canister system to capture and contain fuel tank vapors. Prior to that, they used the "flow guide valve" system in 73 and earlier. So, 74 was the first year for the CARB can, and on page EF-33 of the 74 manual there is a diagram of the evaporative emissions control system. Note that they call out the existence of that orifice. Also note that in subsequent years, they dropped that diagram from the FSMs. So my guess is that orifice was carried forward from 74 on, but they just didn't bother describing it in the manuals. I didn't study each and every manual from 75 to the end, but I took a quick look at a couple of them and didn't find any mention. Here's the diagram from the 74 manual that shows the restrictor orifice: :

On the flat top car models (73 and 74) there are actually three paths for coolant to flow through the intake track. All three of these paths start at the thermostat housing. First path comes out of the thermostat housing and passes through the intake manifolds. Second path comes out of the thermostat housing and passes under the front carb and then up into the balance tube (near the EGR valve). Third path comes out of the thermostat housing and passes through the carburetor bodies. All of those paths then gather back together again at the back corner of the block and from there they flow through the hard line around the back of the block. So I can't tell exactly which of those three paths is the one capped off, but you should be able to trace the lines knowing what you're looking for. If not, take some other pics from different angles and that should help with the ID.

Oh, and what's the next question you want to work on?