Captain Obvious

Thanks Zed for the hook. I'm not "hands on familiar" with the 78 (I have a 77), but I'll do what I can. For 78, there are only a couple things that can turn on the brake light. 1) Pulling up on the emergency brake handle. 2) Low brake fluid level. 3) The brake check warning relay. As Zed Head mentioned, the third one (brake check relay) is tied into the alternator charging system and will light up the brake light if the alternator output drops too low. But it's SUPPOSED to go back out when/if the alternator output rises to normal again. So, I don't have any conclusive explanation for the latched warning light you experienced, but I would start with the easiest... If your brake fluid level is normal and your parking brake handle switch isn't "touchy", then I'd guess your brake warning relay may be having a problem. They fixed a lot of the electrical gremlins by the time they got to 78, but the earlier years have had issues with that relay.

I'm thinking that either someone added that to a car that didn't leave the factory with one, or the documentation is wrong and they put those on all the 78 cars regardless if they were 2+2 or coupe. Maybe they were offering that as an option in 78? Dealer installed?

Cool. My pic is from the 78 FSM:

According to the diagrams, that switch was used on the 2+2s. Present in 76, but not in 74. Don't know about 75.

Cool mod. What's old is new again. http://modelabasics.com/Ignition.htm

Thanks for the input guys. Zed, I've used my OBDII scanner on a number of newer vehicles and the timing numbers are way up there. Like fifty degrees BTDC. That's one of the reasons I started this whole discussion. I was wondering why a 2006 Hyundai can run that much advance, but our Datsuns top out at under thirty. jonbill, I heard the same thing about trying to use the vacuum signal from just one runner. I saw some pics of a "balance tube" sort of contraption to combat that. I don't remember if I saw that at Speeduino, or at Megasquirt (or jolt). In any event, I understand. Neat trick with the idle speed. I didn't know that was a thing. AK260, Yes, that helps. Thank you. So you're running a MAP sensor... But if you have it connected to the original stock source, it's a ported vacuum. Can the 123 deal with that? And what MAP sensor are you running? Oh, and I added fixed dwell to my device today. Seems to work as intended.

Nice. You sprung for the stick-on label? I never got back to you with other stuff... Sorry.

So speaking of vacuum advance and load sensing adjustments to the timing... Aren't some of you guys are running aftermarket ignition controllers or full engine management systems? Are you using TPS or MAP instead of vacuum? @AK260 , @jonbill , @Zed Head

As for the vacuum advance, I'm just messing around here on the bench with the distributor and I didn't want the vacuum advance to move at all. Problem was, my new bearing retainer worked so well that the two plates inside the distributor move so nice and easy now that they almost move all by themselves. For my screwing around, I actually didn't WANT them to move around, so I had two choices... I could either install the vacuum pot, or I could just lock everything together with a different plate and skip the vacuum pot all together. I chose the latter. Since I already had that disk cut as an earlier prototype for my bearing cage, all I had to do was drill a couple holes in it and use screws to clamp everything together. I think in the application on the car, having some sort of "engine load sensing timing adjustment" feature is desirable. The question is... Do you want to do it with a vacuum pot pulling on the distributor, or do you want to do it electronically using a manifold vacuum sensor or a throttle position sensor instead? The point made by John Mortonson in those thread from HybridZ is that you CAN do without vacuum advance completely. You'll lose some light pedal cruise gas mileage, but other than that, running with no vacuum advance at all doesn't really have much impact. The original system does it with the vacuum pot, but I'm just kinda poking around with doing it electronically instead. Re-inventing the ignition controller for the ten thousandth time again.

My laboratory really needs an upgrade. What I really need is big pole barn out-building. I've been told that would make everyone happier. My guess on why the originals were made out of plastic was because it was easier and cheaper to make thousands like that instead of machining them out of metal. There might be a little bit of "slippy" feature of making them out of plastic that would be beneficial as well, but I don't think it's that big of a deal. I just sized the holes a couple thousandths larger than the balls so they would be free to roll instead of binding in the holes. My thoughts on the matter... "They make the bearing cages inside ball bearings out of metal all the time. So why wouldn't it work here?" As far as a retaining feature for the balls... You can see in this pic that I'm holding the plate up off the bench and the balls are not falling through: I did this with tiny deformation marks on the other side of the plate. If you look closely, you can see two very small dots on either side of the ball hole. Those punch marks deform the plate and close down the hole a couple thousandths which keeps the balls from falling through: If I decide I'm going to use this distributor, I could install the balls and then put similar dots on the other side of the plate as well. That would retain the balls in the plate completely. But for all the messing around I'm doing right now, I just wanted to see if it worked. It makes assembly easier because I only need two hands to get in place instead of three. I'm so tired of finding those balls after I have dropped them!

So I was spinning the distributor on the bench again today and I decided I would put the rotor on it just to see what it looked like as it spun. Nothing really bad happened, but I did pick up a noticeable vibration at certain RPM's. I pulled the rotor off and balanced it on a thin piece of metal. It's not balanced around the center shaft. You can see from the balance point off center. That can't do good things for spark scatter, bearing longevity, or reluctor gap consistency: I'm guessing it's because of the metal having a higher density than the plastic portion: I also assume that the extra material on the opposite end is supposed to be a counterweight. I have no idea what brand rotor this is, but it looks like they needed to add even more:

For a fleeting moment I had the exact same thought. Almost even asked about it. But then I thought, "Chris would never do that." I should have let Captain Obvious go free! Haha!!

That's really funny! The bread making thing seems to be happening everywhere, including here. So far, we're pretty good at ciabatta (my favorite), and last night we took our third attempt at making tortillas. The ciabatta is third generation development and is now excellent and the tortillas need maybe one or two more notches up and will rival the best tortillas we've purchased at the store. I say "we", but it's the Royal We. I can only take credit for forming and cooking the tortillas. And of course, the role of quality control and product evaluation. The sourdough starter has been growing on the counter for about a week now? Hope it tastes better than it smells...

I also made a plate to lock the vacuum advance mechanism down hard so I could spin the distributor on the bench without worrying about the plates slipping around inside. There are several threads on HybridZ that talk about the advance mechanisms. Here's a couple links. John Mortonson seems to be a big champion of jettisoning the vacuum advance completely and bumping the static base advance up instead. He JB Welded the plates together completely: https://forums.hybridz.org/topic/21577-timing-an-l28-advance/ https://forums.hybridz.org/topic/49923-advancing-timing/ I didn't want to epoxy everything together, so I made this instead: Not ready for production, but works for locking my distributor together on the bench!

Thanks bud! I didn't start messing around with any of this stuff with the intention of producing anything for sale, but if someone wants to pay me, I'm for sale. Haha! And speaking of such things... So remember the other day when I told you I broke that brittle plastic vacuum advance bearing holder? It was right after I walked you successfully through how to get YOURS out WITHOUT breaking it? : Also remember that I told you I was sure that (using stone knives and bearskins) I COULD probably make something to replace it, but there was no way I was going to go through all that trouble? It was way beyond my pain threshold for an academic exercise? Well, then there's now: It's not brittle anymore.

So I did some reverse engineering of the stock ignition module and patched my contraption into the middle of the box, essentially using the stock module as my VR front end. Then I spun up a distributor on the bench with a variable speed DC motor. And it all seemed to work as intended! Hey... I got the time, right? It's not like I can drive my car!

I'm not sure those screws are a good idea. I'd be worried that driver might slip off the screw head and mess up the paint. How about some spray coating that looks similar? Undercoating or something like that? Bedliner?

Wow, that's pretty bad. There's no way they should be putting a mark on like that. It's just bad practice. So on the upside... Glad to hear you found the smoking gun, and glad it wasn't inside the case!

Well I hope I'm not providing too much reassurance. You're not out of the woods yet on transmission quality. There's still plenty of things that could be wrong that you won't be able to tell until you actually drive it (like bearings whining or synchros not working right at speed), but so far, so good! Just the fact that it's quiet while spinning at engine speed is a great second test after the initial hand spun bench test. So what the heck is wrong with the clutch system???

From your description , I'm guessing it has a synchronized reverse gear? if it wasn't synchronized, it would grind bloody murder if you tried to put it into reverse without disengaging the clutch. Assuming it is a synchronized reverse... What you're doing is using the synchros as a "clutch" (which is actually exactly what they are). You're pressing the two synchro cones together using the shift lever and there's enough friction between the two surfaces to move the car a little. Probably wouldn't happen with warm transmission oil, but with the cold thick oil, you're getting enough energy transferred to move the car. The harder you press against the linkage, the more the car should move. In theory (only), if you were to force those two cones together hard enough, the car would speed up and eventually snick into gear once everything "synchronized" to the same speed. But in reality, you would bend something in the linkage first or burn up a synchro with the heat. So what's the point? The point is that it sounds like the transmission guts are doing that they're supposed to do, and the problem is somewhere in front of the input shaft. Clutch problem (as if you didn't already know that).

Nice work. I thought you were getting a set of aluminum ones from @Mike W ? That never panned out? https://www.classiczcars.com/forums/topic/57438-spark-plug-wire-routing/

Yeah, I figured on your side of the border, the metric stuff was easier to get. On my side, not unexpectedly, the inch stuff is easier. I'm thinking that a press fit would be enough. I was looking at the original bolt in your fantastic pics and it looks like there's a small undercut on the shank end of the wing? Like they could have pressed the wing head on just a fraction of a mm further before it bottomed out? If you think about the application, it's supposed to be finger tight. I'm thinking a nice aggressive "permanent" category press fit would be plenty. Use your hydraulic press to put it on. Just don't shoot the whole thing out of the press sideways into sensitive body parts. Haha! I see what you did there! Any of that (silver braze, TIG) will ruin the plating and necessitate a re-plate.

Coolness. Since the only thing you're doing with the wing nut is locking it onto the stub of the bolt after you cut the head off, the threads there don't matter much. If I were doing that here, I would use imperial hardware. 5/16 (or 1/4 if I wanted a shoulder). I don't know if that makes your hardware choice any easier, but thought I would at least bring it up. So the original wing bolt looks like it was made from multiple pieces as well? I've never thought about it and don't even have anything that runs carbs right now. But it looks like they did the same thing you are doing with multiple parts. Silver soldered together maybe? Or just a tight press fit (which I think would work great for you too). Other input? You could chuck the hex coupler up in the lathe and taper the lead in hole for better target acquisition. It's not as big as the stock one, but you could provide some bevel there to help. I'm still thinking about the other end that threads into the carb faces... Wondering if red Loctite would be good enough there instead of the thin jamb nut. That red stuff is pretty tough. I wouldn't be surprised if the bolt would twist off before the Loctite let go (cold). You could cross drill, pin, and file flush. That would hide pretty well, especially if you're going to re-plate.

Wow. Steve's ability to dredge up that stuff is amazing. Probably can't remember what he had for dinner last night.....

And it seems somehow my previous input was overlooked as well. In response to your request, I posted a bunch of ways people have successfully installed headlight relays. So in case something went wrong with the previous message and the info did not come through on your screen, here they are again. Here's hoping whatever went wrong with the message last time works this time: https://www.classiczcars.com/forums/topic/50416-75-280z-headlight-relay-upgrade/ http://zhome.com/ZCMnL/HeadlightRelays/JudkinsRelay.htm https://forums.hybridz.org/topic/91938-headlight-relay-for-260-280/ http://www.zhome.com/DaveRelay/DaveBuild/DaveInstruction.htm https://www.classiczcars.com/forums/topic/60198-240z-led-headlight-wiring/ http://www.danielsternlighting.com/tech/relays/relays.html