zKars

I've recently been through the wringer on mechanical fuel pumps. I LOVE the stock mechanical pumps and dearly wish to be able to use them more. Silent, plenty of volume to run triples etc up to 250 hp (my educated guess). Stock new pumps put out a CRAP load of volume even at cranking speeds. The cheap "offshore" GMB and Spectra fuel pumps that are out there that look like the stock Nikki/Ampco/Kyosan Densi pumps have been reported here and elsewhere are a ticket to very early failure. I can further attest to this experience. Had a fresh GMB make it about 10 km before leaving a customer/friend stranded. So after much investigation of the issue, I have good news. 1. The GMB and more expensive Spectra are identical inside. The diaphragm and check valves are visually and texturally identical. Might as well buy the GMB ($18.72 CAD on Rock Auto) 2. The problem is with the check valves. The design of the flapper is weak and shitty. The OEM diaphragms are thick and strong and seem fine. The failure is that they stop (or barely start ) being able to pull fuel from the tank. Any air gets in there and they loose prime. If you actuate the pump by hand on the bench in a vise with your finger over the intake, you can barely feel any suction. Do that with OEM pump and it will suck the skin off your finger tip. (Air intake only, no liquid). Now the really good news happens when you want to rebuild your old OEM Pump. Up till now it's been tough to find rebuild parts. I took apart about 20 OEM pumps (all three brands, 14 Z and 6 510 ) and noticed the following. 1. Diaphragms; Depending on age and use, some were fine, some were hard and/or cracked. No surprise. About 40/60 good/bad. 2. Upper diaphragm. Not even sure what the function is of the upper rubber diaphragm, but 100% were soft and reusable. Don't think they endure much hardship. Maybe one was a little stiffer than the others. I'm sure we could fill an long thread discussing what its for.... Please don't here. 3. Check Valves. The real surprise. 100% of them were 100% perfect and appeared nearly brand new. All were clean, no sign of crud buildup or damage or erosion/corrosion. These things are indestructible apparently and totally un-affected by fuel or time. 4. Lower seals. Where the rod passes through to the actuator. About 4 out of the 20 were still soft and usable. Lots of splits and hardness. Ok, knowing what we know about the new copies (GMB and Spectra) and the old faithfuls, and what's wrong and right about both species, is anyone seeing the possibilities here? OEM Body, check valves removed OEM check valves, front and back. Thick solid valve body. GMB check valves, front and back. Thin rubbery floppy material. GMB check valves are held in place with punched nibbins. Very hard to replace the valves. Well, easy to get out, but how do you keep new ones in? You'd have to drill and tap a pair of center holes to use the stock center hold down bracket thingy. Do-able, but.... Are these held in tightly against the gasket? Is there a gasket? Do they come loose with use and abuse? Inquiring minds need to know! GMB mid case with their check valves in place, top view back side of GMB upper hosing. Note different shape of center beam. Top of GMB pump housing. Fuzzy picture like the whole situation.

Pertronix is famous for burning up if you leave the Key in the ON position with the car not running for more than 15 minutes or so. Pertronix II is supposed to be more tolerant of that but I’ve seen failures.

Interesting. Perhaps the root misconception is that the needle is actually more of a continuously tapered shape, it is NOT a series of 1/8” Long tubular sections. Thus you ARE changing the Needle OD continuously as you raise and lower it by small amounts. Even though I can find drawings with both concepts, the first one here is more the correct representation of the actual shape More like this; Not like this:

You can tell I’ve been drinking and thinking again... If the SU needles have richness “stations” (Progressive diameter changes) every 1/8th of an inch, why does moving the richness adjusting knob by as little as 1/4 turn make a significant and measurable change in AFR? The thread Pitch on that adjuster is 1.0 mm, so it should take 3.5 turns to make a one station shift..... Just saying, what the heck is going REALLY going on that no one wants to talk about... Is there more to the amount of fuel that is allowed to leave the jet tube than the simple needle OD/tube ID difference right at the top of the bridge or top of the jet below the bridge? Or a complex function of the various ID/OD changes throughout the jet tube? Does this revelation also lead one to addition tuning engineering? Or just more reasons to drink? Let’s see whatcha’ all come up with on this one...

I could not imagine that the factory would expect the valve cover appearance to remain even remotely “in good condition” if it were shipped as pure bare un-treated alloy. Aluminum was not a “new” material in the late 60’s. It is no surprise they would apply some sort of preservative. Paint however is a surprise to me. Mostly its fun to realize that the bare aluminum assumption is likely wrong after all this time. Another day, another day of learning. Now we can all go off and try to produce a paint formulation/process that reproduces the factory appearance.... I have to go out and touch just a corner of the back of my NOS cover with a dab of acetone and see what happens...

Sherlock Holmes here. Since changing the sender and the dash gauge produces the same result, there is only one thing in common with both scenarios. The tank itself. (other than the wiring) There is therefore, something in the tank that is touching/interfering with float movement at that 1/3 position. Big dent in the bottom? About the only other thing about the tank is the rotational orientation of how you are inserting the sender into the tank. There is a little tab on the tank, and small gap in the sender ring that line up? Really scrapping the bottom of the tank/barrel here... Another test, If you move the sender arm in free air with it out of the tank, does the gauge respond in the same way? (have to connect a ground wire between the sender body and the tank).

M8 bolts have a 12mm head (JIS bolts anyway), M10 bolts have a 14mm head. Same for the nuts that would fit M8 or M10 studs. The four TOP bolts on an EFI intake manifold are M10 bolts, the studs on all the shared thick washer locations are M8.. Only the EFI heads have these M10 intake manifold bolt holes in between the M8 holes that are used on the carb intakes.

Hard to see without disassembling a few, but most of the ones I see do NOT appear to have a flat washer between the spring and the big hex nut #28, unless its much smaller and thinner than I can see. Other than increasing the spring pressure or giving the spring a kind of base, I don’t see that spacer washers are needed for anything in particular. There isn’t anything in the drawing, #29 is just a spring

Here is one example I have.

They are in very nice condition. I would ask that you measure the distance from the lock button hole to the end of the door card. If they are nearly 9 inches, they are not suitable for a North American 75 280z. The lock button position needs to be at 6”. From my research these appear equivalent to the 77-78 280 door cards here. The other thing that I observe is the location of the two large holes where the arm rest mount through. On the 74.5-76, the holes are lower and slightly back compared the later ones. You can compare them to the embossed lines as well. 74.5-76 the holes are on top of the pair of horizontal lines, while the later ones; the holes are above/touch the upper horizontal line and don’t touch the lower one. You can use this to year ID any door cards when you can’t see the location of the lock button in any pictures you might see. Here are two door cards with a ruler to show the lock button location. 77-78 on top.

I've had bearing come with those seals. Absolutely remove the seal. Just pick them out, they are not held in tightly at all.

Yup, that’s new one I haven’t ever seen before. I can see how it could happen. i do have to note that no matter which way you put that bolt in, there is a large cross groove in the splines that the M10 bolt has to pass through, that locks the splines from slipping out of the yoke. Yes, if its in the wrong way, or is loose, the splines can come loose and there could be play, but I don’t see how that joint could come apart as long as the bolt is still in place through the groove. If the bolt falls out, then yes, it can come apart. If the splines were not inserted far enough so that the lock bolt can pass IN FRONT of the entire shaft, than that is a real problem, but I think the over all length constraints would make it hard to assemble all the components without realizing something was wrong. Wish I’d made a list of all the critically wrong stuff I’ve seen on the Datsun’s I’ve touched. Everything from rusted out seat belt mounting points to seats barely bolted down. Trust nothing unless you’ve checked it yourself.

I added some text to the topic Mike started . Worked just fine

I know, any title will do, this one just resonates with me. It should be something more descriptive for sure. "Illustrated S30 Parts History". "Parts History Illustrated" "Parts Progression History, Illustrated" Anyone else?

The Fiche definitely would be a go-to source of From/To date information for most parts history, but it does not give you anything resembling a decent picture of many uniqueness's between parts, or fine details. Only modern color pictures of real parts from several angles sometimes can show the level of detail. Here is one picture where I try to show the difference between the 74-76 door panels and the 77-78 along the back edge to show the subtle angle difference. (77-78 in front). No way the fiche is ever going to give you that.

As an example, here are the three styles of seat slider. I happen to have been embroiled in this discussion recently. S30 1970-1978. North american Left, 240Z, 1970-1973 Up to 7/73 Center 260Z and 75-76 280Z. (Date range....) 8/73 - 7/76. (?) Right 280z 1977-78. 8/76- 78 Rear of the slicers is at the top of the picture. Sorry about that. 240z. Studs in sliders go through holes in seat base. Nut/lock/flat attach (awkwardly !) from underside of metal frame. 260/280 . Round headed hex M8x1.25 chrome bolts attach through slider into captured nuts in seat base frame. Notes that come to mind: Since the way the sliders attach to seat bases is different as well, I should include pictures of the seat bases, but only from the perspective of the way the sliders mount, Not the webbing, or upholstry differences. That’s another thread. I will copy of all this into a new thread In the new forum if and when it goes live.

That is one “H-e-double hockey sticks” bite out of those pulley flanges. Ouch! Maybe just take similar sized chunks out of the other side to keep it balanced? Sand over the edges a bit so it doesn’t catch and tear the belt? Or PM me for a replacement!

Dearly Beloved. I find myself explaining over and over again to various Z owners (all Datsun owners really) about the differences in various items and what year range they belong to. I am tired of doing so, and tires of hunting down pictures and URL's of stuff for them, and would just like to point them to a single URL where they can look up the answer to their question. What better place than our beloved CZCC forum, and what a better way to entice new members! Note this fatigue does not apply to the membership here, but mostly to the ones I try to help on that blessed piece of crap FB....... There are just SO many more soles pleading for help there, than here, I cannot but help wanting to draw them all into our little cult, er, I mean "family".... I understand this is a vast and highly detailed area of discussion, but at the very least, I would like have a basic picture library of items, one item type per thread, in a forum group I think would be aptly named "One of these things is not like the Other". For example. pictures of the three basic gas tank types, pictures of the fuel sending units from each, pictures of the three types of seat sliders, pictures of the 240, 260/280 early and late door cards (my personal bane)..... Door internal/regulator glass/frame differences, etc etc. The list is endless. I am blessed with a decent selection of many of these common items and will start this off by taking representative photos of each of the unique items I have. I will apply date ranges, and will love to have clarifications from the peanut gallery (or any fancy nut you claim represents your level of knowledge) to further refine either date application or other clarification on the topic. We will clearly label each as applying to North american, Japanese , European etc product lines, although for the beginning lets stick to the North American stuff. I suggest the new forum be in Car Talk > Z > One of these things is not like the other @mike , please chime in and let me know if you believe there is a better place or organization structure for this. Others let us know if this is something you'd like to see or contribute to.

@Rerbset58 please post a picture of your pulley. There are several styles. I may have one

Group 24F is what I’ve always bought. https://www.batteryequivalents.com/bci-battery-group-size-chart.html The stock battery frame internal dimensions are 10-3/8 x 6-15/16. In my link above that suggests that a 24F is too wide at 10-3/4, and that 24H and T are better at 10-1/4. I’ve never had a problem with a 24F fitting a stock frame, probably a manufacturer specific shape thing, or the max width is at the base, not around the perimeter of the top. Can’t comment on the correct height, no Z’s in reach at the moment, sorry. Just spotted a good battery picture in one of the threads here. Kinda shows the stock frame and mounting tab at the firewall.

Well my first impression is that the seals in the end there are likely different than the B type 4 and 5 speeds, as the mechanicals are different. Never seen a kit for the A type. You’re going to have to take it apart and look what is in there for seals and then go hunting. If it’s o-rings, finding new ones is likely not that hard. If there is an oil seal, then maybe a bit harder. I have a couple of these transmissions, one of which I plan on recycling, so if worse comes to worse, I can send you the tail housing and maybe it won’t leak. As to the sloppy shifter, I used to put a 1/4” bolt through in place of the pin/C-clip and tighten the bolt down to draw the fork together to remove some of the play. If the fork is worn down and rounded over, you might be able to take it to a welder to build it back up. You can get stiffer poly bushings for the shifter rod receiver too to remove some of the softness there as well. If I get a chance, maybe I’ll tear down that A type I want to scrap today or tomorrow and let you know of any tricks, but usually its just that you get the trans in neutral then push the shifter rod to the left to cause the pin that sits in the shifter forks to move away from them, allowing you to pull the tail shaft off. Just wiggle and twist until it separates.

For the sake of reference, here are pictures of the resistor's where-abouts and appearance in the harness. And a picture of my Fluke VOM showing the resistance value. located just inside the firewall grommet. ok, 2226 ohms. Nominal 2200 ohm. If you were to go buy one, the color code is RED RED RED (2, 2, X100) (then one more band for tolerance). Blue taped to the harness Labelled as a resistor

I'm going to ad a detail about the 280z tach swap that I don't see mentioned here. There is a 2200 ohm resistor in line with the line between the negative coil terminal and the tach signal pin. Here it is in the 76 FSM. Now it would appear from the above discussions that many have not had a problem with getting the tach to work without it, so maybe it doesn't matter, but in the case where you have trouble, adding it might help.

People keep bringing me 5 speeds with chucks of bearing cage on the magnetic drain plug. Been the mid plate countershaft bearing in every case so far. At the very least I’d replace the bearings. Wish I was closer. Aren’t the balls supposed to be inside the races? Not always I guess. The good news is that the cage pieces haven’t reaped havoc with the rest of the rotating parts in any of the examples so far....