madkaw

Inline6---I have actually done many of the things you have mentioned. From the paper feeler gauge to the caliper measurements on the linkage rods. I am confident that the rod linkage is properly set-up. The one worn ball socket is not that bad and have adjusted to where the throttle plates all open at the same time. I am confident that the carb return springs are intact and work well. As far as throttle plates being the same on the carb, I am not as confident because i haven't come up with a best way to measure besides eyeball with a light. To the naked eye the bores are the same. I would think it would be noticable to the naked eye if this was actually causing the cylinder to almost foul out. I have taken the carbs apart at least twice and blown them out. As far as pilot adjustments, they have always been adjusted out the same amount of turns with good results. These carbs ran great!! I have since removed the intake and could find nothing with the gasket. What I didn't like was what I saw inside the combustion chamber from my view thru the ports. Looks like oily grunge sprayed against the side of the chamber. Not heavy, but a pattern on certain cylinders that make me wonder what is causing this. Is this oil from the piston side or the valve side? My plugs don't indicate a oil foul, it cleans off too easy-like carbon. I know I have issues with my rockers being improperly machined and this manifests itself with uneven pressure on the top of my valves(lash pads). Does this have any play in this, I don't know. At this point I am about ready to pull the head and get this issue fixed. I know I have an issue with these rockers, but what other issues will it cause. I need to remedy this because it will only get worse and cause damage that might be fixable. I need to make sure my guides haven't been damaged and my cam also. I know it sounds like desperation, but these tangent issues complicate troubleshooting with the engine. This year is slowly becoming a wash with my Z.

Boy this is getting interesting. This sounds so much like my issue with 40's

No progress at all. My life is getting in the way, but it's an exceptional year for me. It will be winter before we move more on this. By then Shawn(FG guy) will be tooled up the way he needs to be.

The d585 coils I was referring to were advertised as cosmetic defects, but it was chipped plastic at the wire plug- no biggy

Check out my MS3X install thread . It has pics and might help with some options

...or you can make a bracket that doesn't involve detouring your heater hose. Buy d585 coils off if eBay for 15$ each shipped . Buy a stock set of wires for 30$. Buy a Hall effect sensor for 20$ and then drill a 36-1 pattern in your flywheel.

Yes- it's normal for them to swell and get too big. Eventually you might have refridge them to try and shrink them or replace or try cutting, glueing resizing

I am kind of having the same issues, but elimination process was not quite as definitive . If I were you it would take a second look- a looonnnngggg look, you might have missed something. Sure seems you have a blockage, so it should be apparent when looking

Saying the obvious here- but when you pulled the 2 wire was it sparking for sure?

Have you done a compression check on #2 cylinder yet? Swapping carbs would help the process of elimination. Carbs are easy peasy to take off. 12mm on an extension gets to all the nuts. Make sure you don't pinch an O ring when putting them back on

I've got a pretty nice 79 manifold that I won't be needing. I need to take pics of it and look it over. I travel to St.louis area every other ay or so. I could possibly meet you with it. PM me.

I don't see any dash for a S-30 on that site.

Zed- he has carbs on it now

I just had to step away for a while. I had these carbs running very well for some time. What complicates things is I have other engine issues. Not ready for the dark side yet. I love my L6 motor even thru this. I still want to try many other options with my L6 , ie- FI and turbo FI with my Megasquirt. What hurts is I have tried not to cut corners and I still have had issues, but that's part of the hobby I guess.

Run 20 initial with no vacuum advance and you should be good. That will give you 37 all in on most ZX dizzys. Your issue might be more carb then dizzy

I have tried to stay systematic and start with the basics on this endevour. I have learned my lessons from my past. I guess the arbitrary symptoms is what gets me . One time #2 is fouling, then I try to duplicate or verify and #2 looks good. Then I did more driving or running and #2 looked fouled again. As far as AFR's, I am kind of using those numbers as a guide line right now. I had found a tune that was pretty consistant with a certain set of jets installed. In this way I know that my engine shouldn't being running in the 12's afr when it used to be in the 14's. There was never that huge of swings even with weather changes. I guess I need to research a good way to measure the butterflies to make sure I haven't twisted something. I have a buddy that has some SU's sitting around, I might see if he will let me borrow them so I can throw them on there to see what happens.

Can someone give me suggestions as to why one side of a Mikuni would pull more air then the other? I guess I will pull it off and measure throttle plates.

Well I went out to the garage last night to curse my car and I stared at the linkage and thought of what Jon suggested. I just stared at the linkage as I flicked the throttle like a sad kid. I then noticed the rod movements and how they weren't working in sync-AT ALL. So how did I not see this. I then noticed that the ball was slopping around in one of the sockets-that ain't right. The ball end had gotten oversize through wear guess. The more I investigated the more I thought I had something-and I may, but I ran out of steam to finish up. It's obvious now that I had the main linkage/rod in a bind since the secondary adjustment rods were not right. At least I found something definitive and will roll with it if I have time today

Trying to picture how I twist the shaft-slamming the throttle hard? I have noticed a difference between two barrels, didn't think it was significant enough and thought I worked it out by synchronizing. Honestly didn't know to check for that-but I will. I need a better syncro tool. I have the ole thumbwheel and bubble. I have had these running very smooth before so I was doing something right-lol.

I about forget we have this forum which is most appropriate for what I'm going thru. It hasn't been a very good week and the Z doesn't want to run right. I have actually been able to find time to work on it, which usually is a problem. But after hours of troubleshooting and working on the car I seem no closer to an answer.It's one of those troubleshooting nightmares that has caused me to walk away before I do something stupid----like give up Z-ing. Symptoms are erratic and only sometimes can I duplicate. I am scratching my head and loosing heart and motivation. I love my Z, but it hasn't been fun lately just working on it while we have had the best weather all year. I will try and describe my issues-though it will sound vague; I have been around the world and back so my descriptions might seem lucid. The engine sounds like it has a miss and won't idle as smoothly as it used to. It feels down on power. Laboring might be a good description of the idle. At first-- cylinders 4-6 seemed to be the culprit. Plugs looked dark and #4 was the worse. But how does half a mikuni run rich? I also had number look dark, but for the most part, everytime I checked 1-3 looked lean or no color. Now most of this has been idle time in the garage, but those general plug reading were after a drive also. I have seen the plugs 4-6 look both clean and dark during all this troubleshooting, but #4 has been the most consistantly fouled. My AFR's bounce around quite a bit at first . I have dual exhausts so I only have the O2 sensor in one side or another. At first the sensor was in cylinders 1-3 and the reading were not bad, but erratic, not stable at idle. it would run at 14 and start a bouncing routine and then look lean. I switched the o2 sensor to the rear bank and it was pig rich-like 10.5-11 at idle-hence the dark plugs. I had to turn the pilot screws on 4,5,6, in a 1/2 turn just to get the AFR's to 13.5. Keep in mind that my jetting is at a known good setting that has worked great before. I've ran these pilots jets and screw settings with no issues before. I have checked floats and they are spot on. I have pulled the covers after running and they are all at the same level. All my pilot screws were replaced and all the tips are in excellent shape. I suspected ignition or my Megasquirt because of the randomness of the issue. But I replaced all components with a 280zx dizzy and wires and no change. Replaced the plugs too. Ignition timing checked with the dizzy and the megasquirt. I checked all valves and adjusted as necessary-nothing to crazy. Vacuum guage only show.ed 12HG at idle taken from a port on my vacuum log. I thought that a bit low. Sprayed everything down with started fluid and could find nothing. I removed the complete vacuum log assembly and capped off all port openings. So there is nothing hooked to the intake. Checked torque on intake bolts and noticed one exhaust flange nut very loose at the very end of the header. I hooked up a coolant pressure tester to see if pressure was building anywhere --- as in a bad HG. I set the tester at 13psi, the same as the cap and pressure rose slightly to 15psi and stayed. No bubbles in radiator and level seems to be the same. Nothing in the oil. Compression test done 1-205 2-205 3-205 4-215 5-205 6-210 Not sure what to make of those readings, but cylinder 4 jumps out at me a little. I'm pretty sure these are within percentage limits of each other. So I proceed to switching out carbs. I swap the 3&4 for 1&2. I run the car and bingo, #2 is now fouled-I found it. #2 would have been #4 cylinder so it must be one side of my carb. So I switch out pilots, and e-tube(which should have much to do with idle). Now #2 isn't fouling, but the engine still idle like sh!t. I should say that I checked all the O-rings when I had ALL the carbs off. This is what i meant about nothing being conclusive or concrete. I have run and cleaned plugs several times and nothing seems very consistant. I had to walk away after about 10-12 hours in the last two days. Not sure if a bad intake gasket would cause such issues, or a avccum leak in general. At first my gut said HG, and I'm not totally convinced it's not, but no definite eveidence to warrant pulling the head off. Valve timing? Well it's not so easy for me to determine this. I have an adjustable sprocket and I degreed this cam in many moons ago. I will have to really ponder on how I will check my valve timing. I have looked down in the hole to see if my chain adjuster popped out or something, but didn't see anything alarming. Could the chain jump a tooth? Unlikely if not impossible, but there is no quick way for me to determine this. My gut says HG or Valve timing(ignition is safely eliminated), but don't want to go on a gut feeling. Give me some ideas guys

The only other thing I haven't done to eliminate possibilities is swap carb positions around. I'm going to swap the middle carb with the front carb to see if the issue follows or stays. The starter circuit seems to be functioning normally, but not sure how to eliminate it unless I just tape over the holes after removing the 'lid' of the starter. The best I can tell they are very similiar Leon

Anyone explain to me how one half a carb will run rich? I about eliminated my MS as the problem. I ran the car with a dizzy and wires and 4,5 still look way rich. I would assume a bad float would effect both sides of the Mikuni-not just one side. What about fuel pressure? I noticed it was between 3.5 and 4 psi today-could that cause such an issue? I will back off the pressure to an even 3 tomorrow to see if that helps. I know there are many things that can cause a rich mixture, but it seems odd half a carb runs rich. Just trying to get an idea before I start ripping into these carbs again.

Car still no worky! Been on the MS forums and striking out so far. Still fouling plugs - mostly 4,5,6 Checked wiring, swapped around coils , changed plugs. Almost ready to pop on my dizzy- but have to repair it first.ARGH

Your plugs look okay?

You don't think you could fix an existing dash well enough for a master? You understand that our plan was to only duplicate the outer shell exactly and have a thin shell that is held to the frame using stand-offs. We weren't trying to duplicate the inner padding stuff. I thought maybe a spray in foam filler would be sufficient to fill the gaps. Not sure what else could work. Some of those areas are thick and would add a lot of weight using FG. As far as the flange stuff -he showed me the porsche dash plugs. The mold for that dash was several pieces bolted together. Only 5 or 6? I guess the size is the biggest factor? Seems to me it would be tougher then that but I don't know anything about FG.