Zed Head

I see a brass tube with a plastic knob inserted. That is an injection molded part. Those thin walls will be difficult to replicate. The cost of machining is in the tolerances, not the dimensions.

Just realized it's a 280Z. You'll get much better responses if you put your car details in your sig. My earlier reply was for a 73 240Z. Your screen name has 240Z in it. Looks like it's the same system though. p.s. I don't pay attention to the titles after I open a thread.

This thread is a bit bizzaro. I did learn something about the fan clutch though. Didn't realize that Nissan had designed an RPM set point into it. Off? at 1600 or? to? 2500 RPM. Not really clear how solid the limits are. Pretty interesting. Introduced in 1973 apparently. Not clear what year you're working on though. I think that your biggest concern might be your overcharging. That will boil your battery and overheat numerous electrical components. Your voltage regulator is not regulating.

Acrylic will probably abrade and wear pretty quickly. Nylon and polyacetal (Delrin) have what's known as "natural lubricity". And acrylics are more difficult to machine, they tend to be brittle. Since the part is plastic it will machine pretty easily compared to metal. A lathe will offer accuracy and precision, but, for what it is, a drill press and some handiwork with sharp objects should get the job done easily. I guess I'm saying don't make it overly complicated. It's not an engine part. Here's an in-depth article about plastics and friction. If you want to test the original material you can stick a red hot wire in it, or touch it with a torch flame, and take a whiff of the vapors. If it smells like burnt hair it's nylon. If it smells like formaldehyde it's polyacetal. The smell test is an actual test method from the past. Probably not allowed anymore though. Odds are it's nylon. https://www.machinedesign.com/archive/article/21816534/plastics-that-dont-wear-out-their-welcome " The most important semicrystalline polymers for friction and wear include: Acetal (POM) which is rigid and strong with good creep resistance. It has a low coefficient of friction, remains stable at high temperatures, and offers good resistance to hot water. Nylon (PA) absorbs more moisture than most polymers, affecting processability, dimensional stability, and physical properties. However, nylon's impact strength and general energy absorbing qualities improve as it absorbs moisture. Nylons also have a low coefficient of friction, good electrical properties, and resist chemicals. High-temperature nylon (HTN) and polyphthalamide (PPA) extend the nylon family through improved temperature resistance and lower moisture absorption. They ....

Just a thought (more mud maybe). There are other big wires up there that carry a lot of load and could easily be tapped to power the ECU. A relay controlled by the ignition switch and power from one of those wires and you've got solid power and no worries about overloading the ignition switch or those other crusty old wires. Relays don't pull much, and you run brand new wire for the new load. There's a good color wiring diagram in the downloads area, for pondering. https://www.classiczcars.com/files/category/1-wiring-diagrams/

For a one off an Exacto knife and a pierce of plastic rod would probably do it. It's not really a high precision piece. Look at how long it lasted while it was melting. p.s. if you add a relay you don't have to worry as much about the heat. Except for the running lights right next to it. I also ended up putting a relay on my running light circuit. That was tougher though because Nissan buried that wire way up under the dash. My original problem was the solder joints breaking.

I put a single relay on my 76 to take the heat out of the switch. If I recall right you just cut the red wire from the switch to the fuse panel and insert the relay there. I punched a hole through the rubber plug in the firewall to the battery terminal. Full power still runs through the dimmer switch but the combo switch only sees the amps to actuate the relay. The circuit is kind of odd to look at because power comes through the switch from the W/R wire (on a fusible link circuit) then passes through the switch on the way to the fuse box. So the relay doesn't control power in to the switch it controls current out. Instead of supplying the fuse box through the switch you supply it through the relay, controlling it with the red wire out of the switch. I have vague memories of posting (maybe just thinking) incorrect logic about the fuses in the past, I think because my thinking was backward about the current direction. (One way in which the internet sucks. The internet forgets nothing.). I thought that the fuses saw less current with the relay in place. But they see the same current just from a different source, the power still passes through the fuses on the way to the headlights. Assuming my 2022 logic is better than that past logic. I could be wrong. Only adding in case someone sees an old post. Maybe I'll dig it up myself. (Just remembered that the fusible link is actually taken out of the circuit, not the fuses. Rambling...) p.s. if you take a few minutes and study that headlight circuit you see that there is "potential" in the factory setup to run 40 amps (assuming a green fusible link is 40 amps) through that tiny switch if there's a short in the red wire that heads to the fuse box. Seems like the switch might melt before the fusible link. p.s. 2 - the running lights run through the circuit right next to the headlights. It's just a bad design. Lots of heat.

So you destroyed two other BCDD's/TB's? Not good. Anyway, at least one problem down. Good luck.

Multi-quote doesn't work across two pages weird. Had to stick an image in there instead. You had a block-off plate on the other two TB's? Just wondering....

I think that he has a Hall sensor on a modified Jeep CAS. And he has coil on plugs, AKA COP, controlled through the Haltech system. Could be a coil circuit in the Haltech ECU, or the tach circuit with all six coils ganged, or maybe the Hall sensor on the CAS. Lots of things to check. Meter time. Check, check, check , check...

I don't want to muddy up the waters either. But a "full" short would completely fry the insulation and the wire very quickly. That wire has just seen too much current for too long. But there is a load, some resistance, between the source and the ground somewhere. Have you measured resistance through that IAC valve? Easy to do and worth verifying.

Found a few. https://www.classiczcars.com/search/?q=bcdd block plate&quick=1

It's probably the solenoid valve for the vacuum advance supply hose to the distributor. For some reason Nissan only wanted the early years to have vacuum advance in 4th gear. There's a switch on the transmission.

Pretty sure that CO has posted that you can't just put a plate on the BCDD mounting area. There are passages that will still be open, that you have to block. Pretty, pretty, pretty,sure. But not positive. Search around on Captain Obvious and BCDD.

The BCDD is a known idle speed screwer-upper. It's on the bottom of the throttle body. It lets air past the throttle blade under certain conditions. You might try one of the other TB's.

p.s. what's up with your oil pressure gauge? Disconnected at the engine?

I think that the shim is meant to correct for the expansion of the aluminum case when it heats up. And/or it locks the outer race down so it won't spin. It's basically a preload shim. Too loose and the race might spin. That's my guess. I also remember finding that all of the ones I measured were 0.3 mm. Like Nissan figured out their manufacturing problems and they were all identical. The picture seems to show that it rides on both races but I thought it only contacted the outer. Could be wrong, can't remember.

I'm going to guess that the water pump is not pumping or is pumping at a low rate. Maybe there's a blockage. The hot coolant is just moving slowly by the sender right after it picks up the extra heat from the "load test". In the garage with no load, the extra RPM move the coolant just a little bit faster pulling cooled coolant through from the radiator. The gauge needle behavior looked normal, plus it started from the correct spot for an idling warmed up engine. The proposal of a bad sender really just means that it's correct at about 180, but shoots up ~10 degrees / real degree after 180. It might be scary to do but if you load tested at higher RPM you might get a different result. Keep the revs up to keep the coolant moving. Just trying to fit the puzzle pieces together. When you dump the flushing chemicals you might remove the top radiator hose and see what kind of flow you have. Don't drain it, use the engine and water pump to push it out. Another data point...

This is the most likely cause of the noise. The system is not "intact". During normal operation of an engine with normal blowby there won't be very much flow through the valve. Just enough to clear out the gases.

You got my point backward. The "CAI" lets the noise out. The factory air filter keeps the noise in. It's just normal air flow noise.

Put the factory air cleaner back on and see if it's still there. Automotive engineers spend a lot of time figuring out how to quiet intake noise. People pay good money for "cold air intakes" to get that noise.

He said they took it off.

I noticed that too. Plus they edited in footage from behind the car but didn't change the soundtrack. The guy said that he took four trips down the mountain to get the footage. Pretty sure I heard a gear grind in the video also. I think that they just over-produced on the video. It's in the "collector" zone, early car, very original, etc. Collectors don't want to see people beating on their dream car.

I watched the video and don't hear the noise. Are all of the various vacuum ports on the intake manifold used or sealed? Charcoal canister, AC system control, brake booster, etc.