Captain Obvious

Excellent. Glad you found the issue! It's so nice when you really confirm that you found the real problem instead of just waiting for the problem to come back again. It sounds like you nailed it this time. I'd vote for Zed as well, but my polling place is even farther than Timbuk2. I'm not sure my Z would make the trip.

OK. I think I know WHAT you are doing, but HOW are you doing it?

I agree with the above. Those numbers don't look that bad. You know there is an idle mixture screw on the AFM don't you? It allows for more or less air to go around the AFM vane hence affecting mixture under low lower load (idle and light cruise) conditions. Before you go tweaking the AFM, you might want to try opening that idle mixture screw up a little. Counterclockwise for lean. Clockwise for richer. Adjust the idle mixture screw while you have the sniffer up the pipe. There's some description in the manual about how it should be adjusted. IIRC, you're looking for CO numbers which will indirectly tell you mixture. Sorry if I'm telling you stuff you already knew, but stating the obvious is part of my contract.

The spark in the first video looks a lot healthier than the spark in the second video. The one in the second video looks intermittent like it isn't firing rhythmically. What was different between those two videos? Did you change something on the engine between the two?

Good info there. Only thing I would add is some additional clarification about the piston drop... The jiggley bits on the bottom of the suction piston stalk are a check valve. Slow piston rise and fast piston drop. I've seen some problems with those jiggley bits in the past where the check valve wouldn't seal properly in the up direction and hence there was a lean dead spot when you punched it because the piston went up too quickly. My experience is limited, but I've not seen one with any sort of problem in the down direction.

Don't forget that you can put a filter over the white and still be legal. In the front, you could put an amber lens over a white bulb and have an amber result. Same process for red in the rear, like most brake lights. White bulb, red filter.

Neat tapered piston pic Blue. Not saying that I've seen or heard it all, but that's a new one to me. Do you have any writeup of the inended advantages of that mod?

I think it's a federal reg. No red on the front. No white on the rear. Helps you determine if a car is heading towards or away from you. The "exception" is white back-up lights, but in that situation it's OK because even though it's the rear of the car, it's actually headed towards you.

I'm not up on the details of the different pulley designs, but I do know they changed a bunch of different times over the years. You can't see it in the pics, but the one I was messing with was cracked where the drive key went into the center hub. So since the pulley was already ruined, I figured I couldn't make it any worse! Your machinist must've been very surprised when the pulley ring fell off in his hand. I imagine there were a few choice words said at that point! About your carbs and the suction piston beveling, I've never seen that modification before. Not saying that I'm up on all the carb stuff, but I've just never seen that one even mentioned before. Looks like it couldn't hurt. And as for your order of events, I think it would be a great idea to toss your carbs onto your existing engine and work out all the other infrastructure stuff before you do the swap. It would be just one less variable in the mix when it comes to getting your new engine running well. Good luck with the project and let me know if there's anything I can do from the other end of the country to help!

I'm not sure I understand what you did to the carbs... You took some material off the bottom of the suction pistons? Have you got any pics of that?

Well since you brought up pulley stuff. I don't think I've posted these before... A while ago a local Z buddy of mine had a chipped pulley he gave me to mess around with. Chucked up in the lathe: Cutting from the inside. Using carbide on the cast iron pulley: Converting a two row pulley into a single row: I'm sure there are different designs of pulleys, but I was able to work this one and still have the main pulley still attached to the harmonic rubber. This pulley originally came off a 74 260. Haha!! Am I really grown up??? That would be too bad!

I'm interested in an Amco knob with the Datsun logo. I've got a couple extra stock style 4-speed knobs that I have rebuilt/refurbished. Any interest in trading for a rebuilt 4-speed knob?

I thought it was going to be more like this. https://www.youtube.com/watch?v=GmCKvY684WI

Live long and prosper.

Call me a skeptic, but I think a big cap on the alternator is snake oil. The battery is pretty much like a hugely gigantic capacitor already. I could see some benefit to having a small faster reacting cap located right at the alternator or regulator, but a big expensive chromed one is a gimmick.

I've got a newly redone stock system and it's a huge step up from the previous owner debacle I started with. My wallet says I better not go for a ride with someone with a fancy setup!

I'd better get the boys round And do some drinkin fast

I believe that's an oversimplification and it's not that simple. It comes down to "dwell time" and the exponential relationship between time and current which will flow in an inductor. I'll go into the details if you want, but the simple answer would be something like: It all depends on what's controlling the dwell time. If the dwell time is well controlled and is short enough, then you don't need a ballast, but if the dwell time is too long, or if it's not controlled under all conditions (like in a points driven system with the engine off), then you better have a ballast in the system or you'll likely damage something. The electronic ignition systems, especially the newer ones, control the dwell time electronically and can limit the coil current adequately without having to resort to using a ballast. Older systems or mechanical systems do not.

Awesome! Glad you found the issue and glad it was as simple as a new coil. Did you get it done in time for the show?

Trying not to get into too much detail, but there are several different internal constructions used in capacitors. One of the major groups is called "electrolytic" capacitors which means "it contains an electrolyte". The addition of the electrolyte allows for a much higher capacitance per unit volume. In other words, you can have the same amount of capacitance in a physically smaller cap. So the the up side is a physically smaller cap for the same value, but the down side is that the electrolyte is sometimes not a solid and that non-solid electrolyte can leak or evaporate over time reducing the value of the cap over time. Better quality caps last longer. Caps at lower temp last longer. Caps that are operated at lower voltages last longer. I've never dissected an automotive condenser, but I suspect it's what they call an "aluminum electrolytic", and yes, it's capacitance would probably drop with time, heat, and voltage. And as SteveJ suggested, bench testing can't really be done without a meter or circuit designed to measure capacitance. All that said... I don't think that the value of the condenser on the coil POSITVE isn't that important. Certainly not as important as the value of the one used on the coil negative. I'd have no issue using a 0.5 uF instead of a 0.22uF on the positive side of the coil.

OK, you got fuel. We can rule that out. Of course it's "possible" that all six plug wires got damaged at the same time, but it's so unlikely that I'm comfortable saying it's statistically impossible. The single wire between the coil and the distributor however could simulate the same effect as all six plug wires going bad. So the dizzy is at the shop that built it? He's going to check it out and let you know?

Haha!! It's a two-fer!! I believe they changed the shift lever bends a couple times over the course of the first generation and some of them can change how the shift lever comes up through the console. I've not studied the differences in detail at all, but I think it's possible it's stock, but just from a different year? Besides being hacked off short of course. The guys with early year Z experience would know more about the different shift shaft designs.

Zed Head, You're absolutely right. It's not the thermotime. I missed the mark on that and thanks for covering for me. And on your FI relay, that's an exact problem I've seen with other crispy coils. They work fine when cold, but when you put power on them for long enough, they naturally heat up a little because of the coil resistance and cause their own internal failure to open up. Until they cool down again of course... Tough to find sometimes because of the intermittency.

Looks like a great starting platform. Here's my thoughts/observations, etc: I spy with my little eye a California floor temp warning indicator. Makes sense for where the car is. Lots of non-factory wire loom in the engine compartment. Let's hope it's not hiding a nightmare. There's also a lot of what appear to be new parts up there. Makes me think someone was chasing a problem. Let's hope they found it. What's the thing in the engine compartment mounted to the driver's side strut tower? Next to the master cylinder and the windshield washer bottle? Is that a cruise control actuator? Is that a 90-96 shift knob?

I understand the seeming contradiction. I'm not saying that's definitely the problem, I'm just tossing out ideas since the other more mainstream ideas don't seem to be panning out. As a way to explain the seeming contradiction... Liquld gas isn't very flammable. The plugs could be wet, but if there's no vapor coming into the cylinders when you crank it, it probably won't fire. In other words, It may be possible that the fuel on the plugs could be the last gasp of a bowl running dry. Rule it out? Have you got a simple easy to check if there's an adequate amount of fuel in the bowls?