Zedyone_kenobi

I do not have a suitable plug for the PVC yet but plan to pick one up tomorrow along with a plug for my o2 sensor bung. I will try the choke tomorrow but I recollect doing that before with little success but let me confirm for you. No stone left unturned! Have I mentioned you guys rock Getting my o2 sensor hooked up must become top priority. It will remove some of the guessing

Nah, when steve91tt we ran the car at essentially 1 deg BTDC with his distributor and it still did it. It popped when I ran it at 10 deg, 14, deg and 17 degrees, and it fully advanced by 3100 rpm or so. I got my Innovative LC-1 wideband in today. I just need to wire it up and get my exhuast drilled for the metal cupling. I was hoping it would have come with a plug AND a sensor. But it only came with a sensor. I wanted to get it installed with the cap on, then come home and install the sensor. Now I will have to do it a bit backwards. Wire the computer up and install the gage, and then drive to a muffler shop to get the bung welded on and a hold drilled.

I changed out my fuel filter same thing happens. Nothing of note. Should also note my last chance filters in the SU's were very clean as well when I looked at the float bowls I put a vacuum gage on the manifold vacuum going to the power brakes. After the engine is warmed up, it pulls 19-20 psi pretty steady at 750 rpm. NOTE: I checked out my exhaust slip flanges from where my 6-2-1 header goes from 6 to 2. They were a few turns loose each. The one that goes from 2 to 1 I could not get to without jacking up the car.

That is VERY generous of you Steve! But I cannot do that to your daily driver. I would never ask you to. Not yet anyway ! HA HA. I would rather just buy the mikunis and webers and have those as a back up to my SU's, or have my SU's as a back up to the triples. I wish I had an easy answer to what this was. We have picked the low hanging fruit. Now it is time to find the more obscure things that have a drastic effect. Things like the vacuum leak come to mind. When I go more than 3 turns out the car just stumbles and dies when it tries to idle. Perhaps I should try to open up the flappers a bit more to keep her running. A wideband will tell me how lean or rich I am at idle so that should provide some insight to that issue.

I have spent some time thinking of this actually Captain. The answer varies so wildly with the results. I do not forsee the wideband being so cut and dry. I hope it does, but in reality we both know that it will be XXX at idle, and YYYY at 2500 rpm, then ZZZZ when it is popping. I am hoping to see a trend. If I know I am leaning out, then I can try to find out where in the fuel delivery I am leaning out. Is my fuel pump providing enough fuel, is the float level adjustment right. Is unmetered air entering into the system. If I know I am rich, then the list gets easier. Try to find out where the extra fuel is coming from. the thing is, all it does is put me into the right ballpark, and gives another data point to help diverge ideas from one another. It also is a quantifiable piece of data which directly relates to the engines running. My thought is that I should not be running rich here and lean there too much. My car is stock except for the header and the custom curved dizzy. Head, cam, block, etc is all stock. Stock SU's should be able to compensate for any small variances between my setup and a totally stock setup. Perhaps my engine is not totally healthy, although that would surprise me. Maybe my cam is not totally up to snuff, but that would surprise me as well. Your question is one of great importance...and one I shall have to deal with eventually.

I cannot go more than 3 turns out as the car will not run anymore. It stumbles so badly it barely runs... I took off the PCV and blew into it from both sides... only could blow through it in one direction I will cap it though and go for a drive..

With the float hung upside down, I picked up the float and the instant it touched the needle with the tang, I took the measurement. It was about .55" as per the factory manual. This differs from the SU video as he showed the float top parallel with the float bowl cover when held upside down. Maybe I should ask Bruce for an explanation of this.

I currently run 17 degrees BTDC per the european spec dizzy I had mine recurved to match. I do not run a Vacuum Advance. I have made the runs with the BARE SU;s with no air cleaner (just plain easier to adjust quickly), with the air cleaner base on but no filter or housing (to get the benefit of the air horns), and with the air cleaner. NO noticeable difference either way. Get popping from the exhaust in all part throttle situations near 4000 rpm. I just do not see it being a fuel delivery problem when I will run at WOT, but not part throttle

I have 2 extra fuel filters lying around. I will put one on when I get home today before I check out my car for vacuum leaks. Cant hurt.

again, webers or mikunis haha

Vacuum leaks is my next check. It just makes sense. I think it is safe to say we have ruled out SU oil as a cause. It popped with 2 wt 12.5 wt 20 wt It popped with SM needles and stock OEM needles Pistons are moving up and down in the domes at the same speed. Car has a great idle. Car ran noticeably better with SM needles Here is what I have NOT done: I have checked fuel pressure from my brand new fuel pump, which was good, but I have not checked volume. OR pressure while the car is being driven. But I ruled that out as if I can rev to 6500 rpm at wide open throttle I am getting fuel. I have NOT checked if the fuel level is right at the top of the jet opening in the carb body, I just assumed the float bowls being properly adjusted was okay. I have not done a proper vacuum check of my power brake line for leaks (will do that today) I have not checked for a lose connection of my header to my exhaust pipe, but have checked most of the bolts on my header to my cylinder head, but not all. I have not installed a wideband O2 sensor yet, but it will be here tomorrow which should GREATLY help narrow down things in a direction of goodness.

Man, that is tough, I have no idea, it seems to pull okay, but I have only ever driven one other classic Z and it was stock. I would say it feels like a stock Z madkaw. It revs pretty nicely at WOT. Of course, the tach go bazerk when I get close to 6000 rpm

I have not checked for vacuum leaks around the exhaust guy. I did check for manifold bolt tightness, and all the nuts on the studs were as I left them. All the carbs are tight. I will run an extensive battery of vacuum checks when I get home with my vac gage. That is easy enough. I did that earlier, and I think I got around 20 " if I recall. I wrote it down in my Z car journal. Still it cannot hurt to check.

Guy, I will check out my exhaust tonight to be sure.

Thanks very much Guy. UPDATE: I am about ready to throw these freaking SU's in the river. After I shoot them. THe 20wt oil did absolutely nothing to the problem. If I gradually push the throttle about an inch, the car pops loudly through the exhaust. If I floor it it will pull hard through all 3 first gears. Guy, I have a thought that you may be on to something. There is just no reason these SU's should not work the way they are... What the hell would cause popping and a complete loss of acceleration at part throttle but works when at wide open throttle. I am going to put the SM needles back in and call it quits until I get my wideband. I have had it.. screw these. Maybe I need a time out. spending 1499 dollars on webers or 1650 on mikunis is sounding like a far better option at this point! HAHA

Nice setup! My lc1 comes in this week. Let me know how you powered it. I was thinking the CIG lighter may work

wow, that thing is really going to be nice! Keep up posted on your progress... I love those older VeeDubs

Thanks for your advice madkaw! I certainly appreciate it.

I made my evap system back to 100% stock. All hoses that are suppose to run to the tank, run to the tank. All hoses that are suppose to run to the engine and filler neck, run to the engine and filler neck.

I will put that on the list after I try this 20 wt. I wonder what the 71 manual says to put in it. I cannot imagine it would be anything different. I have been running the SU oil for a while now as MSA says ..."this is the perfect oil for your SU's".... If it is 12 wt, I cannot imagine why they said that. When I first got my SU's from Z therapy, I put 20wt in them and that was as good as they ever ran. Then I remember switching to the MSA SU oil because... well because it was SU oil! I somehow thought it would work better...

Good ideas guys. Blue, the reason I am on the oil right now is I sort of half way ran that test yesterday with the Marvel Mystery oil (about 3 wt according to interwebz sources) and any gradual roll on to the throttle seemed okay, but any drastic change at all the engine just about stopped running. THe more I moved the butterflies the more drastic it became. So here is my logic. Flawed as it may be. Right now my pistons drop perfectly in tune with each other. With or without the top of the carb screwed in. So I know there is no hang up in the needle or the piston. CHECK! With SU oil (12.5 wt, thanks 30 Ounce), it popped and sputtered at about 4500 rpm With Marvel Mystery oil (3 wt ), it popped far worse at about 2500 rpm I am now running straight 20 wt. We will see when I get her on the road today, if the trend continues, this SHOULD get me on the right track... But I will not rule out a 15wt oil if this works as well. Like a bad sit com... The saga continues...

UPDATE: 5pm this evening I get all the carbs back together and fill them with a lighter oil. I used Marvel Mystery oil per somebodies suggestion. Car now pops and sputters at any throttle change above 2200 rpm. It is leaning out way to fast as that piston rises so much faster. Definitely a step in the wrong direction! I will clean out the carbs again and fill them with straight 20 wt oil. I have no idea what the SU oil is that I bought. I only know the marvel mystery oil made the plunger FAR easier to push up.

H&K, Very nice...

Just wanted to thank all of you again for the help. I am usually pretty savy with carbs. Was a bit of a Holley guru in my V8 days. and these SU's seem just wonderfully simple, but often the most complex things are the simplest. For the life of me, though, everything I do seems to result in ziltch. They are so clean you could eat off of them. This is truly a strange case. After I get the wideband stuff, it will at least point me in a direction...lean or rich.. well lets hope so.

It seems I am right with the first two methods Blue. Nothing is really far from being 'spot on'. Everything appears to be as it should. I am going to blow out all the fuel lines and put everything back together. Then I will get some clear tubing and try to mark where the float comes up on the car. But all of this is just for ****s and giggles until I get my wideband installed this week! Should be here tomorrow or wednesday.