Captain Obvious

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

The design concept is three pulses per crank revolution. Right now it's just using a signal generator on the bench for proof of concept, but if I get energetic, I'll put a variable reluctor front end on it and connect it up the pickup coil on a distributor. In theory, it should work with points. All the math is set up for six cylinders and three pulses per crank revolution. I can get those pulses from either points, or the VR pickup in the later distributors. In theory. Haha!!

You got collets for the lathe? You might be able to run the bolt through the collet (head inside the collet body and threaded end sticking out). If you can do that, you can set your compound on the lathe for the angle you want and cut your point easy-peasy. You can do the same thing with a regular chuck (instead of collets), but collets are easier on threads because of the wide gripping surface. Chuck jaws have a tendency to dent the threads. They work, but it's easy to mess up the threads. However, if you've got an unthreaded shank on the bolt, it may allow a land to tighten down a 3 or 4-jaw. I doubt I have pics of that kind of operation, but I'll take a look.

Haha!! Yeah, if I put in some provision for vacuum advance, I've re-invented the electronic ignition controller for the n+1000th time!! Completely remove or lock down the mechanical and vacuum advance mechanisms in the distributor and do it with a little module instead. I'll let you know when I've reached the point where I'm willing to put this thing on my car and take it for a drive. Haha!

Wow. That needs to get back to O'Reilly's corporate. I don't do a lot of business with any of the stores, but that's pretty cool.

It looks like the top side of that sheet was uncoated (but rusty). Is the underside coated with anything? Paint? Tar? I'm thinking that maybe between a rust hump on the top side and maybe some coating on the underside, you're measurement is a couple thousandths too thick. It would only take five thousandths less to make that a 1mm thick sheet. In the end, however, I don't think it matters... People will (should) use what they can get, and although I haven't checked, I suspect finding 1.0mm thick sheet isn't the easiest thing to do in these parts.

And on a related note, I've whipped up a little electronic gizmo prototype that applies the mechanical advance in an electronic manner. Reads an input pulse train and effectively outputs a pulse train advanced with respect to the input. The curve looks like the stock curve with a couple adjustments to the numbers to make the math work out easier. 10 degrees advance up to about 1200 RPM Then 1.3ms of delay from 1200 up to 2500 RPM (which mimics the advance slope of the stock curve) And then caps off at 19.5 degrees above 2500 RPM Not sure there's any real value in what I did, but it was an attention diverting academic exercise. I think just that is worth something right now.

Thanks for that. So I'm assuming that 34 degrees was total timing? But on the dyno at WOT, that would be all mechanical, right? No vacuum. And our engines top out at just over half that for the "base" mechanical. Sounds low.

A wise man Eddie Murphy once said... "Every time they cure something it come back stronger."

Sweet. Now you're the resident drawing expert. I love it when a plan comes together! So what's up with the wing bolts and hex bass thingies? You got a pic? You can chuck hex up in the lathe easily... Just sayin'. And I can probably teach you how to cut metric threads. Probably. Old dog.

lmgtfy