mr mikey

You're so right, can't believe it wasn't carb related after all . I don't idle at 400rpm, but I also didn't want it stalling right below idle speed. I've got it set to idle when fully warm at 700rpm, but if I'd set the gap to 700rpm(.006"), then it would stall the second it started to go below that. I guess I could've set it to .005"(mathematically stable down to 550rpm), but my gauges go from .006-.004", no .005" feeler gauge. I guess what I did, was give myself a 300rpm buffer zone below idle speed, as a precautionary measure.

Ok, I kept going down in size of feelers until it would idle at 400rpm, so I'm guessing the size it requires is .004". I had to mill the bottom lip off each fin so it wouldn't scrub the pickup, but everything seems to work fine now. Thanks a bunch, this thread can be closed now.

Ok, set to .010", and it idles down to about 1300 then loses spark. Set to .008", and it's down to about 1000rpm, any lower and it loses spark. I tried adjusting to .006", but the very bottom of the "fins" on the dizzy shaft are touching the pickup. The fins look like they're straight until the very bottom, and they stick out a little. I figured I'd been ripped and gotten sent a worn out dizzy, so I ordered a new one and the fins are the exact same way. Anyone notice their electronic dizzy's "6-point star piece" on the shaft being shaped like this? The gap throughout top to bottom is the same, except the very bottom, each "fin" of the star piece has a lip that sticks out a little farther?

Ok, I reversed the polarity on the ignition control module, where it reads the spark trigger, and it fires right up and idles fine(with a slight hiccup every so often). So used that time to make sure carbs were set, advance was correct, etc etc etc. Only prob with running reverse polarity is you cannot rev it any, it'll only idle(set idle to 700rpm). Reversed the polarity back to correct, and it still does the same thing. Base timing is at 9 degrees advanced, advance tube plugged. Everything is doing right, but now have an issue. My old service manual is well used, especially in the ignition areas. I need to know what to set the hall effect trigger to, as far as gap is concerned. I cannot see the numbers, too much smudge. Local guy told me that I can't just set it to almost touching, without touching, because it would cause the ignition module to see too many breaks in the magnetic field, and the spark control would be all over the place. So I guess I can't set it like I do the gap on an old magneto engine.

Well, I found something interesting. When I began to idle it down, the moment it starts acting up is when the spark becomes erratic, then I lose spark and it stalls, then regains spark the second it begins to reverse rotate. Talk about weird.

The first ones are the same as what I had on my 70 240z, can't find them now and have no idea what brand they are, can anyone help? The second ones are Keystone Turbines(no clue if they're legit or knockoffs though), with some cheapy tires on it currently until I can get her finished, then the circuit tires go back on. and yes, those first tires/wheels are a mix-match, we got American Bronze tires put on them, but one was defective a couple weeks later, took it back for exchange and all they had was Remington, so I have (3) American Bronze tires and (1) Remington. For 30yr old tires, they're still doing great, no cracks forming or anything. They're 185/80-13's, used for cruising only. The circuit tires(not pictured) are 205/60-13's.

Well I stopped trying to figure it out for now, got alot of body work to do. But if someone could confirm their advance at these 3 rpms, it would give me an idea of which way to adjust. With the vac advance hooked up, in neutral, no engine load. 18 degrees @2200rpm, 15 degrees @2000rpm, 12 degrees @1800rpm. If I adjust idle to 1700, you can hear it go from a perfectly smooth idle to an every so often hiccup, like it's either loading up or ignition is being cut for a split second.....then adjusting down to about 1650rpm will make it die and do it's reverse rotate thing. Floats are set per Blue's post, and that's with the jets set to 2 turns down.

Yes, I can take more pics. All vacuum hoses that lead directly to a vacuum source have been blocked off, so any/all accessories you see with vacuum hoses are just dead hoses. I'll eventually mill down the blockoff plates I made for all the components and install them, just been super busy with work. Also, the heater crossover channel(preheats manifold)has been blocked off internally. I need to figure out how to get the screw-in hose barbs out to replace with brass plugs.....they look like they're in there pretty good, didn't want to break one. I'll get more detailed pics when I get back, gotta go outta town, cousin is getting married in Indiana. I don't like that drive.

I borrowed a pair from my buddy off his 240z, and they did similar, but what they would do is let you idle it down to 700 and stay running fine for a while. Then after about 5min or so, it would just act like you turned the key off(with the exception that it would still reverse rotate and spew smoke from the relief vents of carbs).

No, not on the base timing setting, it said in the instructions that it wasn't necessary, because the adjustments were fully mechanical. I did use a timing light to check max advance at 3500rpm, and it is sitting on the 36 degree mark on balancer.

I set it per the instructions for the dizzy. Set the dizzy so the rotor is centered on the #1 plug wire contact, align the dizzy to the 0 mark on baseplate, stab dizzy so baseplate mounts to engine when balancer mark is aligned with 0 mark on timing tab. Then loosen dizzy hold-down and rotate the dizzy so it's pointing at 9 degrees advanced on baseplate, then lock-down dizzy.

I thought the same thing about the timing, especially the way it reverse rotates, but it not hard to crank(actually very easy to crank).....my camaro is base timed at 18degrees advanced, so I know how an advanced engine sounds when turning over . The linkage has been checked for slack and worn joints and such, it all seems to be fine. I can spray wd40 around the throttle shafts to check for revving from vac leaks and the idle speed never changes(unless I accidentally overspray into the barrels haha). When I bought it, I was able to drive it the 2hrs to my house, but it chugged and rolled coal when I tried to pull any real hills. Tore the carbs down per the video and found a bunch of crud in the bowls, so I went nuts with a toothbrush and scrubbed all the internal components, and readjusted per the video.....it hasn't been right since. Car is '74 260z, Engine is '74 260z, carbs are '72 240z. Distributor is a "NOS/OEM" electronic ignition distributor listed for a 260z with the GM electronic control module.....it had the Crane(Allison) Fireball 2000 or whatever it's called, but it kept going thru control modules(found later that the setups are finicky when it comes to quality). I have all the answers, except the one to my question lololol.

The smog stuff is actually unhooked at the source, only using blocked tubes to seal off any leaks, I haven't gotten around to making the blockoff plates for everything yet, as this current issue is draining every bit of mental capacity I can put towards the car . I'll get some nipples to cover all the spots, or if you think maybe the parts are internally broken and hemorraghing through to the exterior, like a vac leak thru the housings.

The needles are in the same place, but when fully warmed up, it does get a teensy bit of sooty exhaust when you get on it good with no load on engine, so I might play with the height of the needles a little.

Here's how she does when easing off gas, started shaking a little at 1800rpm and fell on it's face at 1700rpm.