Zed Head

MSD most likely uses what's called a zero-crossing trigger, I think it's the basis to the variable reluctor electronic ignition. The variable reluctor produces an alternating current, from positive voltage to negative and back, voltage crosses zero twice. It's only consistent, timing-wise, going one way. The modules are designed to trigger one way, either going positive or going negative, so if they see the wrong direction of the crossing they are unstable. Swapping wires puts them back on the consistent zero-crossing direction. As I understand things, at this point in time. It's not a flaw, it's just the nature of the technology.

I haven't used an MSD module but I see one thing that might be part of your problem, or just a separate consideration. You are using the ZX ignition module (B and C in your diagrams) to trigger the MSD 6A module. You have two ignition modules. You might bypass the ZX module and use the red and green wires from the VR inside the distributor to trigger the MSD 6A. The ZX module, E12-80, is just one more thing to break down and offers nothing to the MSD 6A system. With the E12-80 module out of the picture you would wire it just like a 280Z electronic distributor (magnetic pickup instructions). You might still have a tach problem but your system will be more dependable with the E12-80 out. If I read things right, you would use the violet and green wires to the magnetic pickup in the distributor, and the gray wire to your tach adapter. 6201 instructions. http://www.msdignition.com/instructiondownload.aspx

Disconnect a hose and see if fuel is pumping. Or just loosen a hose clamp and see if fuel leaks or squirts out. Your work would be so much easier if you had a fuel pressure gauge connected.

This part just clicked after I made my other post. You have the "early" hubs on your 1973 car. So RockAuto sent you the right parts for a 73, according to the data available. Interested to see what they do, I'm not even sure that there are real people there. It's a huge operation, many more brands and models than just Datsun and Z cars, and might be primarily robots and warehouses. From what I've seen, most parts houses are all working from the same database. So they all make the same mistakes. Try to find a transmission rebuild kit and you'll see. And, there are several threads on this forum about the early scalloped hubs and the rotors. Part of the puzzle...

Aside from the fact that the internet is full of stories about Nissan changing things mid-stream, and blending parts as they make the change, what are the dimensions of the rotor that you have? At least you can confirm that you either got the wrong part or you got the right part for the wrong hub. Measure from the mating surface of the wheel to the disc surface. I can measure that through the slots in my wheels. Finding and getting the right parts is part of the fun. If you can't get a full refund, you might make your money back by just selling them to someone here. With the dimensions in hand at least they'll know they're getting the right part.

Take the small wire off of the starter solenoid and turn the key to Start. If the pump is wired right you'll hear it whining and you should hear some bubbles in the fuel tank as the air is pushed out. The pitch of the pump will change when the lines get full pressure. If you have a pressure gauge you'll see what's happening. Did you cut the ends off of the old wires? It's possible to wire these pumps backward. They'll run but they won't pump. Another possibility.

You didn't say what year your 240Z is. Your profile says you've owned a 72 and a 73 240Z. the internet says that your part number is good for 73-78 2X0Z cars, so if you're talking about a 73, you're in the gray zone. Could also be that someone changed your front suspension. I would take the focus off assuming someone else made a mistake and make sure that you didn't first.

I'm not an expert, that's just what I've read. Other sources say never remove the cam towers. But almost everybody says to get the matching rocker arms and pieces, unless you want to buy new rocker arms. The key to knowing if the cam is installed correctly is if it rotates easily. Also, don't use the torque specs. in the "How to Rebuild..." book. There's a typo, it's too high. Any idea why your cam broke in the first place? Is it the original cam shaft or a replacement?

The recommended way to install a used camshaft is to get everything else that was used with the shaft along with it. The cam towers, the rocker arms, the wear pads, everything. Keep everything in the same order and orientation it was removed and reinstall that way. Your camshaft might have broke because someone installed just the shaft in the old towers and it flexed and fatigued.

Have you checked the magnet valves (solenoids) for proper operation? That's where the vacuum is distributed to the hoses and actuators. Maybe you have one that's sticking and not opening to atmosphere to release the vacuum.

You're on the slippery slope of guess-and-hope...

Groovy. Here's a trick I've seen used to loosen things that are on the hub that might help. Put the hub back on a wheel, tighten it down with a couple of lug nuts, place the wheel face down on the ground, then stand or sit on the wheel while you loosen the bolts. Or you might just hold the wheel with one hand and loosen with the other. Whatever works.

That might be a temperature switch for a dual point distributor. It's kind of a mystery mechanism that Nissan kept up through the early EFI cars. It's not mentioned in the Emissions chapters, only the Electrical chapters. It advances the timing when the engine is cold. Maybe to keep the idle up or maybe it really is for emissions. Described in the Ignition section of the Electrical chapter. Measure resistance on those wire ends and see if it's a switch or a sensor. If it's the switch, it only matters if you have a working dual point distributor.

I haven't replaced rotors but I think that they are bolted on to the hub from the back. Do you have the hub and rotor assembly off of the car or are you trying to remove the rotor with it on the car? Sounds like you might have it still on the car since you're asking about bearings. If you had the hub and rotor off you'd already have removed half of the bearings and seen that they're pretty easy to replace, although some beating with a punch and hammer might be required. Use a brass or aluminum punch so you don't score the bearing race seats. Rockauto has some good tips on making sure the new rotors work right (click on a link for any rotor and a new window will open up). Runout needs to be checked.

Nothing wrong with wanting a more modern 6 speed transmission. If there was an easy swap, there would be a bunch of 6 speed Z cars out there. But there is no easy swap, not even an adapter you can buy. I think that I've seen some adapters that people have built for themselves, but they're not available for purchase.

Going to the most basic of basics, you should have been able to choke off the air supply to control idle speed. The engine will only spin as fast as it can pull in air to burn. The fact that you couldn't get the idle speed down suggests that you had extra air coming in from somewhere. The only air supply the distributor might supply would be from the vacuum advance canister, leaking. Just a thought.

Check the hose from the solenoid to the actuator. Small vacuum leaks will cause an increase in idle speed.

Are you using the factory 1976 distributor or ZX or aftermarket? Could be a factor. Does your tang look like Picture #3 in Post #4 when the timing mark is at TDC on the compression stroke?

Check AC-38. There's a diagram. "L" means blue wire color. You should have a 4 speed switch. Looks like power is passed through a set of resistors to control speed. The two wires to the blower should be easy to find and hot wire since you're almost there in your picture.

Actually, you'd have to remove the oil pump and shift it over a tooth. The distributor only fits one way on to the quill. One thing to do before going too far would be to verify that the timing mark is at zero at TDC. Your damper might be bad. Why would anything have changed? Have you had the oil pump out? Rebuilt recently? Some background on what's been done recently might give some ideas. By the way, the line to the charcoal canister is ported vacuum, only applied when the throttle is off idle. It's the right place for it. And the thing on the intake manifold is probably the top gear solenoid. Doesn't help your problem, just adding.

Got my cutting pasting screwed up in Post #21. Here's the link to the modification - My cheap Z32/RB26 Tranny shifter Bracket. - Nissan RB Forum - HybridZ

It's for an RB swap but the concept should work. You'll have to measure for your project. - Z32 Transmission Shifter Relocaters - Group Buys - HybridZ and the 240hoke part mentioned, for an L6 - Z32 Transmission Shifter Relocaters - Group Buys - HybridZ Use Google and search "site:hybridz.org z32 shifter" and you'll find a bunch of reading.

My S30 lessons have stalled recently also. I need something to break. Found a good reference on exhaust concepts, linked below. If you're tuning the exhaust system to generate pressure waves (think two-stroke engine pipes) at specific RPM ranges then a constriction can be useful. But just adding a random constriction to maintain velocity will just give random results. Why not go down to 2" or 1.5? Exhaust System Technology: Science and Implementation of High Performance Exhaust Systems On the shifter - there's a guy on Hybridz who came up with a very simple modification for the shifter bracket and rod on the Z32 transmission. A few cuts and welds and the lever is where it needs to be. The part is called a "support bracket" in the attached drawing.

I think that LeonV might be just disagreeing with your premise that restricting flow "should actually give the motor a little bit of a performance". That's been shown to be an urban legend, wive's tale, myth, etc. when referring to primary size for headers. You might be confusing your turbo principles with NA principles. You want hot gases in to the turbo so that they can do work on the turbine. With NA you want cool gases so that they take up less space and get out faster. Your vocabulary seems to be outpacing your knowledge. Actually doing something is the best way to learn.

I think that Eurodat was just pointing out the possibility of a whine. No guarantees that a simple flange swap will be easy and fix the problem without creating a new one. It seems to be that some people work on their diffs and end up with a whiner and others don't. But no guaranteed way to fix the whine if you get it. Nobody has asked how the flange could possibly get bent? It's pretty stout and would be surprising to have enough force to bend it without damaging something else. Are you sure it's bent, or could you just have internal damage or a bad bearing causing a pinion shaft wobble? You might be just wasting time with a flange swap.