Zed Head

Is there a "Z sighting" thread? Not sure.

I think that there might be a Pathfinder thermostat that fits, it's just not official. But it is Nissan. On the GM HEI module the supposed 4500 RPM limit is really just a red herring that David Vizard created, based on his interpretation of the design. He never verifies what he thinks happens. He just didn't like it and voiced an opinion. It's in one of his books. And, 4500 V8 RPM = 6000 six cylinder RPM, spark-wise. There are many options out there. You have to be careful on the old brand names. The companies are long gone, most of them consolidated under one corporation and parts made in Asia. MSD is part of Holley and Holley just got "owned" by private equity money. https://www.empowermidocean.com/ https://en.wikipedia.org/wiki/Holley_Performance_Products "On September 22, 2015, Holley acquired MSD Group, which includes brands MSD, Mr. Gasket, Lakewood, Accel, Mallory, Hays, and SuperChips. On March 12, 2021, Holley announced they had entered into a definitive merger agreement with special purpose acquisition company Empower Ltd (Tkr: EMPW) that will result in Holley becoming a publicly listed company on the NYSE under the new ticker symbol “HLLY”."

Do you really need a scope? A slow turn of the switch and a meter should tell the story. It would have to be controlled by the width of the moving contact. If it bridges On and Start it's "bumpless", if it doesn't there's a bump. p.s. the bridging would be only at the "between" point. Not when it was fully to the Start position. It might be in one of CO's links but I remember people having problems with their Haltechs or other EFI systems losing communication from Start to On or vice-versa. The computer resets and it causes problems. Can't remember what the cause or solution was though.

I had a switch on a 78 parts car with a loose S pin. The staked area had loosened. I rapped it a couple of times with a chisel and fixed it.

The ignition switch is very simple. You could just measure continuity through the pins on the back and determine if it's bad. The pins are marked.

Looks like the switch locks out the EGR system at low engine temperatures. Can't tell if the switch is normally open or normally closed though. You didn't say what temperature the engine was at. Emission Control (EC) chapter.

These engines seem to throw rocker arms occasionally, especially if they've sat for a long time. Maybe the valve guides are tight since they're new, or they're drying out as it sits. Apparently today's detergent oils drain more fully than non-detergent. (Obscure factoid I picked up somewhere). But since it's open you migth as well check the wipe patterns. Maybe they're off and a rocker arm pad caught an edge. There have been some posts on the forum about bad wipe patterns causing a racket. The notch is on the gear which is bolted to the camshaft. I think that the only way the cam could be off is if the locating dowel was missing.

Also, something I've noticed in these types of conversations - the focus tends to be on "maximum power" which you'll only see at wide open throttle, high RPM. Most of us never use that area. I think that getting the vacuum advance dialed in will have more affect on driveablity. And, probably, the RPM at which maximum mechanical advance is "all-in" as they say, whether it's 28 or 36. Like if you compare the 72 and 73 curves above you'll see that 72 is "all-in" about 800 crankshaft RPM sooner than 73. 2000 versus 2800. They used to make machines specifically for setting distributor curves. You can spend a lot of time on it. https://www.ctci.org/sun-distributor-machine-the-ultimate-tool/

We had a thread conversation a while ago about how 34 degrees seems to be the optimum mechanical advance limit across a wide range of engines. I posted some dyno run videos and maybe some other links. Not sure why, I think it has something to do with just the nature of the piston movement (you can cover a lot of degrees near the top with very little piston motion) and the basic design of most older engines. Anyway, if you browse around the internet you'll see 34 degrees a lot. There's also a thread out there, either on this forum or Hybridz where a guy was setting timing by ear, expecting to hear some knocking when he was "maximized" but he never did and ended up leaving power behind because he was over-advanced. He discovered it later when he did some dyno tuning.

People have just eyeballed the disc over the spigot/pilot bushing to get it centered with good luck.. I'm pretty sure that you can get it centered also by eyeballing the edges of the disc on the flywheel. Just make the edges even all the way around. Sometimes, you can just wiggle the transmission around and/or lift it up and down a bit to get the shaft started. The input shaft actually has some play in it so even though the transmission body might be aligned the shaft itself can be a bit low. Your input shaft has a pretty big chamfer cut in to it so should actually be easy to start. Put a small amount of grease on the tip it, it might help. But, I've had a pilot bushing that was just wrong-sized. It wouldn't fit in the crankshaft. I had to break it in to pieces to get it back out after getting it halfway in. So sizing errors are possible. Might be worthwhile to spend a few bucks and get another of the same brand just to be sure it fits the input shaft. Then maybe replace what's in there with the known quantity.

How far does it go? How big is the gap?

Open the AFM vane before you open the throttle it should rev because of the extra fuel if it's a fuel problem. You didn't say that the vane actually moves with air flow. Maybe it moves a little and stops. Might be that the AMF is not right now. Work and work right are not the same thing.

Are you sure the AFM is plugged in? You can check at the ECU connector. That's actually the best place anyway. I'd say try the fuel tweaker but if it won't rev with no load then it's probably not seeing the AFM signal. Also, you might pop the black cover on the AFM and be sure the vane is moving when the throttle opens. Quick and easy. If the vane doesn't move the ECU doesn't add fuel. Here's the tweaker for future ref - http://www.atlanticz.ca/zclub/techtips/tempsensorpot/index.html

I left something out in the post above. It's confusing. The MAP reading is the pressure left over in the manifold after vacuum is pulled. So, to make a new table of MAP pressure readings from a vacuum reading table, you have to subtract the vacuum reading from absolute pressure. We all live under approximately 14.7 psi all the time. 760 mm Hg. 100 KPa. 123ignition's web site actually has a tutorial on it. But if you read too much of it the subject gets even more confusing. It's basically physics class stuff. https://123ignition.com/support/create-curve-tutorial/ " Regarding the vacuum curve, this is a little bit more complex. 123ignition works with absolute vacuum in stead of relative vacuum. The advantage of absolute vacuum is, it works also when you drive the car on high altitudes. In case of relative vacuum, you have to adjust the ignition manually. The values in the original Bosch graph are given in mmHg, 123ignition works with kPa. First we convert the values to kPa and crankshaft degrees instead of distributor degrees. You can type in Google: 80 mmHg to kPa 0 deg @ 11 kPa 10 deg @ 27 kPa Now we have to convert the relative values to absolute values. Atmospheric vacuum at see level is 100 kPa. So 100 kPa is our base point. Al values below 100 kPa is vacuum all values above 100 kPa is pressure. in this case we have a vacuum curve, so our result will be: 0 deg @ 100 – 11 kPa = 89 kPa 10 deg @ 100 – 27 kPa = 73 kPa"

Yes. I consider the brass tube to be the locater of the spring, just holding it under the contact point. The forces aren't really trying to separate the parts. At worst they have to resist a side-load, mostly resulting from friction as the switch is actuated. You can look at the pictures of the parts and see that there is little (no?) sign of distortion of the tube even though there was, apparently, enough heat to melt the tip. Actually, the flatness of that melted part in the picture is kind of surprising. That takes a lot of heat to cause that.

Here's a red 70. Didn't sell. $43,000. It got a higher no-sell bid the first time it was on BAT. $65,000. Uh oh.... https://bringatrailer.com/listing/1970-datsun-240z-79/ https://bringatrailer.com/listing/1970-datsun-240z-94/

Here's a good conversion tool for converting mm hg (millimeters of mercury) to pressure. Manifold absolute pressure (MAP) is the pressure inside the manifold. So it is kind of the inverse of vacuum readings. A high pressure number will need low ignition timing advance, whereas a high vacuum number will need a high ignition advance. Anyway, for the purpose of creating a MAP map you can just take the points on the Nissan curves and convert them to pressure. Convert the mm-Hg to whatever unit your 123 is set for. I think that there are two settings, metric and imperial maybe. Not sure. Pick a curve, convert the numbers to make a new table to match what 123 software needs, plug the numbers in. https://www.onlineconversion.com/pressure.htm p.s. I had to wake up some sleeping (deeply) brain cells to get in to this. No guarantees that it's correct but I think it's close. Feel free to correct anything.

Here's 1973. If you just get close to these you'll probably be fine, for starters. 1973 was starting to lean toward emissions goals. I haven't really compared the changes to the early curves so can't say if they're significant. Edit -actually you can see that they delayed the advance in 1973. Retarded timing is cleaner than advanced. So the 72 curves probably add a little bit more mid-range power, I'd guess. That's the tradeoff.

You could match a curve from a 240Z. Should get you in the ball park. The curves are in the FSM. Pick an early one, they later ones are emissions focused. Here's 1972. Don't forget that distributor speed is 1/2 crankshaft speed. And, therefore, the degrees are double also. e.g. 9 distributor degrees = 18 crankshaft degrees. You'll want to study up on the vacuum and MAP readings also. It takes a little bit of thinking. The curves are for the two types of engines and their distributors that were offered in 1972. It's detailed in the chapter.

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.