DaveR

Okay I'll scope it all out. Was very strange indeed that this morning it was fine and this afternoon was no good. I've driven maybe 200 miles on it since rebuilding basically everything so it really must be either something silly like that, or my poor clutch adjustment.

EDIT: This is reference, but I don't believe it's the clutch. More likely a fuel pressure or delivery issue. Maybe in the carbs as well. Everything replaced and carbs rebuilt, so its pretty surprising to have this kind of issue. Need to get a fuel pressure tester... --------------------------------- Something strange happened today that was new. After driving to work in the morning and things feeling pretty normal. It wasn't an aggressive drive at all. On the way home there was a lack of power transfer at certain RPMs/torque range. I first noticed it going up a hill, the car seemed to be struggling to have the power to push up it. It originally felt like it was in too high a gear and didn't have any torque available, but even in lower gears the same thing happened. Just push the throttle, engine sound might change a bit but RPM's and speed cap out very slow. ~20-25mph tops. I've never felt a clutch slip, I suppose I would have expected the engine to continue to rev higher but the speed not increase accordingly. The engine really didn't rev higher, even though I could hear it trying to do so. If i disengage the clutch the engine rev's happily. I ended up having to limp home in higher gears but super low RPM. I couldn't really get the car over 30 mph or so, the power just wasn't being transferred. Also whichever gear I selected I really couldn't go beyond 2k RPM or so without getting no power transfer. Very recently I did a clutch slave adjustment. I was trying to back it off at the slave so there was a little play with the clutch pedal fully up. (so I wasn't putting undue pressure on the diaphragm spring) Maybe I went too far? I would assume this failure mode would be that I couldn't disengage the clutch enough to change gears, not that the clutch would then slip. Am I all backwards? I suppose I could have backed off the adjusting nut too far and there is now more clearance than there should be between the withdrawal lever and the release bearing. But again, I wouldn't expect the clutch to slip in this case, just that I couldn't properly change gears.

anyone ever seen a new brake drum with a groove cut out of it on the outside? Can't tell if its for balancing (if so its a big groove) or just an defect during production. I would guess balancing, but I'm not super keen on the size of the cutout. Seems like quite a bit. Plus how can it need that much material removed to balance, and the other one needed nothing at all? A bit disconcerting.

I mentioned the hose clamping trick to a guy at work and he STRONGLY recommended not to do that. Thinking back I had the front two corners vice griped for about a week when I was doing my strut install. The flexible lines were newly purchased by me at the time, but I may replace them again in case I did any damage. Totally not necessary but for $5 a corner and with brakes, I will just do it. It does give me the opportunity to clamp them down again for testing though, which I will probably do... although I don't know what it will tell me really. I suppose it could isolate the MC entirely which might be useful given what I write below... I am starting to suspect my master cylinder may be the culprit, and let me explain why I don't 100% trust it... The master cylinder is a new 7/8" Sanyco brand. The guys who sold me the car were getting it drive-able out of 30 years of storage and they replaced the MC and the front calipers/pads. What they didn't realize is that this swapped the circuits on my 71, and they were trying to bleed the front circuit that was connected to the rears since they didn't reroute the hardlines or something to that effect. Compounding this issue is that the rear cylinders were leaking and spewing fluid out whenever you braked, and if my memory serves me one of the reservoirs had no fluid in it, or it drained out rapidly.... So yea, there could have easily been a time when there was no fluid at all in one side of the MC and the brakes were attempting to be bled a lot or lightly driven. I have no idea what this could do to the seals, but its bringing it back into the equation as a possible culprit. Especially since its right at the start of the pedal travel.

Also I read about a trick where I can clamp off the flexible lines at the front corners and check pedal feel in that situation. Maybe I'll do that and see if anything changes. Would be a good indicator if there is one or more corners that are causing issues.

Checked a few things tonight. Front pads were from a new loaded set of calipers. (installed before my ownership) Things look good, and the pads are basically right on the discs and not backing off. I don't seem to have an issue with the shims as far as I can tell. Runout of the front rotors is .003 to .004". More than I'd normally want, but in spec to the FSM that states max of .0059". I do not get vibration under braking and the braking surface looks good so I'm not inclined to replace them right now. They will soon be the only non new component in the braking system with the exception of some of the proportioning valves. Rear drums have a run out of .020 to .025". Maybe even .030". So quite a bit back there. I think I'll replace those as they are right around the max allowable diameter anyway. It makes adjusting them quite hard without a uniform surface to set them to. Shoes look decent enough with lots of material left, but for the low cost of them I may get new just to check it off the list. The only two things really remaining are to replace those drums/shoes and readjust, and to smack the front calipers and bleed them a bit more. After that I will really be at a loss.... or i've just been creating a problem that doesn't exist.

Nothing about the braking actually bothers me. This was until a fellow long time Z enthusiast drove it last year and commented that the pedal was spongey and dangerous, but I never felt that way prior to him saying that. I figured he knew what Z's should feel like and maybe this was contrary to what I felt was typical brake pedal operation. Your comment about the reaction disc is actually something I hadn't thought about, and I would imagine its there and doing its job properly in this case. It really may be operating properly and I am just over analyzing it. That said the drums and rotors surely still need replacing. Pedal pulsing isn't bad. I actually rode a bit with the e-brake partially engaged to try and smooth out the contact surface on the drum. Return springs on the shoes are new so I think that's in decent shape. For now don't rack your brains any more unless you enjoy doing it, I'll scope out a few more things and hopefully get some more clear direction.

Your bleed order is different than I did, so maybe I read it wrong when I looked last. I am doing 2 person method. I did many many pumps to the rear drums and know i cleared it all out because the bubbles from the MC install made their way through. The car does not nose dive during braking, but I will double check soon and test my further adjusted wheel cylinders. I am starting to suspect the drums/rotors being out of spec. The rear drums are definitely out of round and not helping things. They are close to the max allowable diameter so I will probably replace them anyway. I'll do the rotors at the front as well because why not. I have a dial caliper so I may measure for grins, but I imagine I will replace them no matter what. So yea, next step is to replace those components and see. I'm still pretty keen that its not air in the lines from the bleed operation... but I can't 100% rule it out jussst yet. Maybe I'll rebleed the drivers rear again to correct my order just in case.

The master cylinder was new as of last year, but I have always had this issue. I have adjusted the pedal stop and accounted for slack in the pedal clevis hole, and also the booster rod and MC seat is perfectly adjusted. Went to great lengths to get the rod properly set. It had to adjust quite a bit. I know for a fact that the moment you touch the pedal you move the push rod on the brake booster, and that is basically flush or a hair off the MC piston surface. Did a test with the MC unbolted and someone feathering the pedal and watching the MC push off the mounting flange. I have been working off the FSM, but again something isn't adding up. I'm thinking that the 1" before the super firm pedal may just be typical operation? I've never really ridden in a car where the moment you touched the brake pedal it was super firm... At least not a car with a brake booster.

So my original metal fan and clutch aren't decoupling. Nothing new to me, since I got the car on the road last year it has never worked. Since I can't get a fan clutch for the metal fan (and because its dangerous) I will replace it with plastic fan and new clutch to match. I have some plastic fans from a friend, but I've read a bit about them cracking and inspected mine. These black lines are cracks, although in some places they line up with the molding lines of the fan. Can get a small screwdriver down into them. No bueno. Guess I won't be using this 8 blade version. The 7 blade one I have looks better, so I'll go that route. Or just buy a new one, but they aren't cheap. As for the fan clutches, I am figuring out which version to buy. I've read Aisin makes decent ones and is the OEM supplier for some makes. For whatever reason the compatibility chart for it (AISIN FCN001) seems to only show the 71 240, 260Z's and the 280z all years. I would imagine this should work on any of the plastic fans right? The 7 blade and the 8 blade both seemed to fit the hole pattern of the old plastic fan clutch I have lying around. seen here and other places (rock auto) https://www.amazon.com/Aisin-FCN-001-Engine-Cooling-Clutch/dp/compatibility-chart/B008EEYJ2O Is a suitable OEM clutch still available? I tried to figure out the Nissan part number but got a bit confused with all the different years, even though they all seem compatible with each other from 240 to 280z's.

Okay did a little more troubleshooting. First off, the movement of the brake pedal. It moves the first 1/4" pretty easily, and the next 1 inch with some resistance but not a ton. After that its very firm. Pumping the brakes does nothing to stiffen it up, its always the same. Front calipers are installed correctly with bleeder up. When I bled the system bubbles did finally make there way through originally. Besides in the calipers or the MC I'm not sure where bubbles could reside. But given what I wrote about the pedal I think i'm probably pretty okay as is. I think I was overstating how much the pedal moved softly, I was surprised the measurements were relatively short at 1" before it was very firm. Other info: The rear drums aren't great, but they aren't too too bad for now. Def out of spec but maybe the shoes will even them out. If i get vibration back there under braking then i'll know. Tightened up the rear drums a bit more. Now with 3 clicks on the E-brake the wheels are hard to turn. 4 clicks I can't spin them by hand with the wheel on. With the E Brake off I can get about a 1/4 rotation before they stop on their own. I'll give it a shot like it is.

In my car I can push the brake pedal about 1/3 to 1/2 of the way down before much of anything happens, at that point the brakes feel pretty normal and behave well and predictable (in my limited experience). I am trying to figure out if and why I should have such a gap in the pedal travel before the business starts to happen. I suspect the rear drums and their adjustment. Here is some backstory: 1971 240z New: master cylinder rear cylinders front caliper/pads Rear hardware Old: Rear aluminum drums rear shoes Master Cylinder was successfully and convincingly bench bled. Pedal Push rod and slop are adjusted and minimal. The moment you push the brake pedal the MC starts to actuate. All corners fully bleed. (pushed a ton of liquid through it) Order followed Driver rear, pass rear, pass front, driver front. Master cylinder is aftermarket (Sanyco) Front/Rear circuits successfully swapped. Front circuit now closest to the firewall. Both outlet ports of the MC have Residual pressure valves. I have no idea of what Value (I know ideally front should have 2psi and rear should have ~10psi) So I believe the problem is in the rear corners. Here are some things that worry me: E-Brake grabs, but fairly high in the travel. I know I have not properly adjusted the rear shoes outward far enough. This car sat for 30 years (in storage but still) so the rear drum surface is far from pristine. I have not turned them and had a fresh surface exposed yet. I need to check the material and see if there is enough. Rear shoes should be fine, but may be grooved to match their drums over time. So I'm fairly certain its a matter of adjusting the rear click wheels, but its a hard thing to do. This problem is made worse by my not perfect rear drums that give uneven wear surfaces and make it hard to evenly adjust the cylinders. I tried to do some reverse E-brake yanks to try and get the self adjuster to work but didn't have luck. I was considering maybe pulling the E-brake to about halfway up and adjusting the cylinders until they are very tight, and the backing the E-brake off. I drove around a bit with the E-brake at like halfway up in and attempt to try and wear down the drum surfaces and smooth things out, but I haven't inspected yet. Any tips would be very welcome. Next step is to pop the drums back off and check how much material is left and maybe try to tighten them back up. Very hard to figure out a good way to adjust them. Thanks

I don't know frankly. I would imagine they are very near each other, neither being overly low. Neither stood out during my research as the lower option

May I ask what cars you would be comparing the ride to? Or if you are looking for a plush touring car ride? My daily driver is a 2005 Subaru STI with stock suspension. Definitely a performance car ride, although nothing like an aftermarket setup. So compared to this the Datsun feels good and similarly sporty. My purpose for the springs was less about the lowering and more about ditching the saggy old springs while I was replacing a blown strut. While it did lower the car a little compared to what fresh stock springs may have been, it was far from slamming the car. So, a slightly firmer linear spring with a noticable but reasonable amount of lowering. Did you not want to get eibach springs? They seem to be the de facto progressive option. And I do believe in most cases people's issues with them are probably incorrect installation.

Some of the people that looked into these in past threads mentioned that their attempts to contact Vogtland ended with the Vogtland rep not knowing the part number. Presumably because they were a special order production batch for a small group which would make sense. Maybe by now with multiple runs they are more in the loop. Anyway, I'm personally unaware of a way to make progressive springs with a uniform coil spacing, or at least a method that they are likely to use in production. (Varying the tempering at different heights in the coil spring for instance) Springs like Eibach have a clear difference in spacing at different positions that demonstrate this. Vogtlands are uniform throughout. (and also pretty impossible to tell top from bottom, I don’t believe they have a correct orientation FYI. Both ways fit pretty good in the spring seats when I installed them) Again I don’t add this to defend my position or argue about it, just because I wouldn’t want you to desire progressives and not get them. Progressive or not I am happy with my set, so either way they are a good option. I have also not had any problems with the car not being level. In fact, if you want to a new linear & slighted lowered (and stiffer than stock) spring I think these are one of the few lower cost options available. Cheers

I believe that's what they told you about them being progressive... But I would put my money on that being incorrect. I don't know if that will change your decision at all, but yea. That is counter to what I found during my research of them. http://www.zcar.com/forum/10-70-83-tech-discussion-forum/363090-stagg-shocks-struts-vogtland-lowering-springs.html#/topics/363090?page=1&_k=t2fop0 They talk about exact spring rates here.

They are not progressive. My ride quality is pretty good. I have no complaints. Springs are stiffer than stock, for sure. I haven't had any issues over bumps thus far. I have urethane bump stops but in my somewhat limited experience I don't think I have ever bottomed them out hard. Overall I am pretty happy... but you may have trouble finding them now as many places that listed them (ebay & brandcarparts) stopped stocking them a while back. Maybe they have more now but I don't know. I got them because I wanted a small amount of lowering, to not deal with the possible uneven problems some have with progressives, and a slightly higher spring force for more composed handling. In my research of them initially I didn't read anyone that was unhappy with the harshness (or lack of) in the ride. I unfortunately do not have miles on the car with the stock springs to offer a comparison.

FYI my car shown here has Vogtland 240 springs. It's hard to see the tire lines with the shadows in the pictures there. But maybe its useful to you. They are 14" wheels currently. I have nothing to compare the ride to in my car, as I put them in before really driving it. But its not noticeably harsh at all, and I daily drive a Subaru STI.

Thank you for reaching out. Good to know about the availability. Did he have any statements about them being unsuitable for street use? Or any other information that might lead you to believe they were anything other than the newest general use model? Thanks again

Thanks, I will look into it. Although it would worry me a little buying them via CL, but that's definitely what I am after.

@7tooZ If you can reach out that would be most excellent. Trying to get my options lined up so I can get any orders that need advanced notice in the works. Appreciate the help.

i haven't gotten great answers when I have talked to distributors. They call the z light a lightweight and in some cases race wheel. It has been confusing enough that I am not confident buying it as a street wheel without much more compelling testimony. They also seem to only mention the z light, and it seems strange that their only offering is a race only wheel. Which leads me to question the information Unfortunately their website doesn't have model numbers, so I can't pull any useful information to clarify from it. If someone knows definitively and I have missed that, please let me know. Just don't want to end up accidently with a set of race wheels when I may have to put in the order months ahead of time

My reason for asking was if the Z-lights are in fact, the racing wheels. I was and am still not 100% certain. Beyond that, I am sure race wheels are super light and can't take general wear and tear that comes along with public roads. I feel that maybe with racing wheels there is a bit of assumption that they could theoretically fail, which is the price you pay for a super light wheel that pushes for absolute minimum weight.

I reached out to Panasport last night actually and will update with their response. I find it strange that their distributors I've spoken to seem to be a bit clueless about my questions/concerns, but this may be because I was reluctant to accept their recommendation of the Z-light being suitable for street. Hopefully Panasport confirms things, and I can go about shopping for prices. In the interim, if anyone should happen to come across a 15" set and wants to point me in that direction, I would be grateful. I have a bit of time to let things unfold organically.

That's kind of what I figured, but when reaching out to distributors they only seemed to have the "Z-Light" wheels. Can someone definitively confirm that Z-Lights are racing only? And if that is the case, is there a model I could look into sourcing new from Panasport suppliers that is for street use, and if so what model? I believe this is the FZ model, but again distributors don't seem to offer it any more. Maybe the FZ has been discontinued like the FS before it? also, I appreciate the offer BGM, but really would want them silver/chrome and in 15".