Zsomething

So, I am up and driving with the round top carburetors on my '73. The car fires up perfectly after sitting for a couple of weeks when I was too busy to drive it. But, I have a problem now with starting facing uphill. At first, I thought it was just me being rusty with the 5-speed. Now, I think there is no torque at low rpm under load. When I went out to a quiet hill to test it out, it would lurch forward with each engine rotation (sort of like it is only using one cylinder). If I hit the clutch fast enough (after a few rotations), the engine won't even die sometimes. On flat roads, it's perfect. On substantial hills, it's undrivable. and everything in between. I just put new round top su's on. So, the 'smog stuff' is still present on the balance tube. But, none of it is attached yet. I have a mind to hook it back up when all is running well, because I don't particularly hate clean air. So, I have rubber vacuum boots (probably not fuel resistant) over the currently unused vacuum ports. So, is there a good set of steps to go through, or a list of things to check for a vacuum leak? Is my problem something else entirely? Edit: I started to try to spray carb cleaner near the places that might leak. But, the can that I had wasn't atomizing very well (at all). So, I'll grab another can tomorrow. Thanks.

Who would have guessed: regulator regulates? I thought maybe my electrical system alternates between working and not working. Seriously though, thanks for confirming my suspicions. It helps to have someone say what you knew was true, but didn't want to believe. I'm not too scared of the wiring. I'll probably go with the ZX alternator, or a similar adaptation. This parallel thread has a discussion: http://www.classiczcars.com/forums/showthread.php?t=27677 Just doing a quick google search these came up too: http://www.nk.ca/~zcar/pages/articlepages/alternator.html http://www.zcarcreations.com/howto/voltreg.htm

The battery is new. So, I don't think that is the problem. The ammeter goes from 1/2 to 3/4 depending on the rpm. To test this should I just measure the amps and volts at the battery and at the alternator? The brightening lights and slow-to-fast blinkers are annoying, but tolerable. Can this affect spark too? It seems like the coil would put out a hotter spark with more amps, at least. (and I have to think an MSD system- which I don't have- would barf all over itself.) Will a new regulator fix the problem, or is it something that I should just get used to? Thanks.

I tried to avoid using the thick spacers because I heard that they don't allow the proper flat washer-lock washer-nut, although I did not try it. I am sure that lots of people have had this exact problem. But, I didn't find much info on it searching. So, hopefully the next person will find the two solutions: use thick spacers, or experiment with a combination linkage setup. Sounds like a pretty good deal to me.

I was out driving today (a minor success in itself), and I noticed that the ammeter rises with engine rpm. Additionally, the headlights get somewhat brighter and the period of directional blinking varies, which leads me to believe that the amps are indeed increasing (as opposed to a gauge issue). Should I suspect the alternator or does the voltage regulator control the amperage as well? Is this even a problem? Thanks.

Basically, the problem was that I was using the short linkage from the round tops (second picture). The shorter linkage had two problems. First, it allowed too much axial movement. Second, it did not allow the existing maintenance screw to be used (fourth picture). Third, it did not allow the carburetor to return to full close, because the angle is incorrect. The third problem was unacceptable. So, I fixed it by combining the round top lower linkage (which matches the carburetors) with the flat top upper linkage (which matches the balance tube). After doing this, I adjusted the threaded rod on the firewall to be the correct length with no slop, and now all three problems are fixed. The first picture is the flat top carburetor linkage, which does not fit the round top carburetors. The third picture is an axial picture of the flat top linkage. The angle between the ball end and the screw that pushes the carburetor butterfly open appears to be greater than the linkage for the round top carburetors. The fifth picture is the round top linkage that is on the car now.

I'll see if I can get a picture tonight. After thinking about it a bit. I think the problem is basically that the round top su setup had thick spacers, and the angle on linkage between "the ball shaft" and "the opener" was appropriate for the bigger spacers. But, the small spacers moved the carburetors closer. Basically, the carburetors moved closer with the smaller spacers. So, the throttle linkage is no longer correct. Anyway, a picture is worth a thousand words (or a million of my words). So, I'll get those up.

I finally got the round top su's on this evening. I've plugged all the hoses to the extra stuff on the balance tube, for now. The pieces are intact. The egr is still present and hooked up. But since I removed its vacuum source, I don't think it will be opened. I turned the key and it started running. It is popping gas out the carburetors a bit. But, I think this is expected for being completely unbalanced? So, I am feeling good and the rpm's start to rise to 4,000 with choke and 3,000 without. So, I attempted to adjust the ilde screw. It didn't seem to have an effect -- all the way in or all the way out. Looking a little closer, I realized that the tab that should oppose the idle screw is about 1/4" away from the carburetor body with the screw all the way out! The throttle linkage that goes from the balance tube to the carburetors is the same length. But, the angle between the ball joint to the pad appears to be something like 10 deg. difference (just guessing). So, it looks like I will have to adjust the screw on the firewall linkage. Hopefully, I have enough extra room to make it work. Are there any other places that I will be able to add slop? Should I try those first?

When I was putting the su's back together, I put a bit of grease on the needle to lube it. But, it occurred to me that may not be a good idea, because any grease stuck in the nozzle or on the needle will affect the mixture profile. It seems like the fuel will dissolve the grease pretty fast. However, the precision of the needle ground makes me think it might still have an effect that will decrease over time. Further, it seems like a non-oil-based lubricant could have a long lasting effect on the carburetor performance. Does anyone have any thoughts? Am I missing something?

I picked up 3.25" springs with 1" S hooks. I'll play around with the geometry and geometry and how much tension to keep on it when the butterflies are closed when I get some time tomorrow. I should have plenty of heat shield to work with to make it as tight as I want. Maybe 5x80 means something different to the referenced poster. But, 80mm is WAY too long (which anyone that looks at the screw, or thinks about it a little, will realize). I got a 5x25 which is also too long. It looks like it is probably 5x20. Anyway, I figure that I can get a nut and a lock washer on the end now, since I couldn't find the star washer and the extra 5mm doesn't hit anything. As for the firewall linkage, there is a little bit more back and forth play than I would like. So much, in fact, that the linkage can come completely out of the far pivot point. I'll probably put a shim of some sort on the firewall, if I get around to it. But, it doesn't seem like too big of a deal. Next step is to static set the carburetors, hook them up, plug the extra vacuum holes, and (with some luck) tune them.

I think the screw attached to the egr that I was worried about is what is referred to as the "maintenance screw" in the ztherapy video. It sounds like I can get away without this by using the brick on the accelerator method suggested in the video. I'm heading to the hardware store now to get the stainless springs. I am going to shoot for something like this (or a little bit less so I can put in sturdy S hooks): I'm also going to pick up a 5x80 countsunk screw with "external star" lock washer (which I mangled during the removal of the old throttle linkage). Source: http://www.classiczcars.com/forums/showthread.php?t=17320 Thanks for the help guys.

Thanks. I was pretty sure that I could chuck most of the stuff. But, I wanted to be sure. And since I have already broken off one screw and stripped/mangled several others, it seems unlikely that the things will go back on. I would like to keep the egr, if possible. Because, I think that plugging the exhaust hole might require a little more than jbweld. Do you have any ideas on where to run the metal tube that went from the egr servo to the port on the rear carburetor. I think it is carburetor vacuum (maybe?). But, the round tops don't have a port on the rear carburetor. Perhaps the egr is more trouble than it is worth... Will any good springs work? I'd hate to wait in the mail for something I can get at the local hardware store. Thanks!

Bruce Palmer answers some of these questions here: http://www.classiczcars.com/forums/showthread.php?t=27596

I finally got all the old gaskets off the round tops that were bolted to another manifold. I hooked up the linkage and I was feeling good until I realized that things don't match exactly right. First, I realized the screw that limited the return motion (attached to the egr) does not hit the pad on the firewall throttle (not sure how to call it) shaft. It looks like the pad is supposed to oppose a screw. But, it doesn't match the flat-top assembly and I don't know what the earlier style looks like. Is this a problem? The picture below looks like it has the flat-top stopper. What is the function of this screw? Second, when I fiddles with the assembly a bit, I realized that the butterflies don't return to closed after releasing the throttle. After reading this thread http://www.classiczcars.com/forums/showthread.php?t=25818 and this thread http://www.classiczcars.com/forums/showthread.php?t=17320&highlight=fast+idle+screw, it looks like I am missing return springs. My manifold more-or-less looks like this one from the thread http://www.classiczcars.com/forums/attachment.php?attachmentid=17997&d=1177913434, except I don't have the springs. Can anyone suggest a quick-term and/or long-term fix for either of these problems?

Haynes calls the screw the "Slow running adjustment screw". I think I'm going to see if this will come off and then jb-weld it. Also, I'll probably just remove the "Throttle closure delay" and be done with it. But, I don't think it will hurt to leave it there for now unconnected.