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NA&CH

Stalling issue(under throttle)

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 I've never worked on three screw SUs but I recall that the float cover must be rotated to remove it. If you're referring to the float pivot pin, it should just push out of the float cover bosses with finger pressure.

 Fuel running out of the stacks would indicate that a float is stuck, needle and seat are leaking or the float level is set too high.

  I think the markings on the butterfly are from ZTherapy. Premier SU rebuilders in Salem Or.

 Is the piston pin you referred to, the brass jet needle? If so the needle may be bent or the nozzle may need to be re-centered. Try screwing the mixture adjustment 2 1/2 turns down from the top and see if the piston is still dragging on something.

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Thank you mark. I meant the oil dip stick. When that is in the piston is tough and not smooth. I order some gaskets and su oil for the proper parts. I thought the markings were Ztherapy. I have a call into them about their carbs. But if I have a set maybe just a rebuild. They are from 04 though. 

Chris

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The oil will give a lot of resistance which is normal when trying to raise the piston but it should rise (and fall) smoothly. 

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The rear carb I push and it works freely. It also has the return spring. 

Front carb when I push the pin it is a struggle to push it and it "comes down" no clunk. A slight sound. 

I have ordered a new coil and electronic ignition. PerTronix system. The gaskets for float and Misc screws for the balance bar. Also a call into Ztherapy. 

Chris 

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If everything is working properly, the pistons should be hard to lift with a finger, but should fall easily. So the one that lifts easy has a problem. Something is wrong with the check valve jiggly bits on the end of the screwed-in stalk.

Also, I'm not sure what you meant when you said that the rear carb has a return spring... If you are talking about the spring pushing the piston down, then they should BOTH have springs under the dome.

Other thoughts? I don't like the looks of at least one of your needles. It looks like it's installed too deep into the piston, and it also looks chewed up and worn some at the hilt where it has probably been rubbing against the nozzle. The nozzle looks to be worn oval as well due to that contact. Dome/Piston/Needle/Nozzle alignment is very important, and the three screw round tops can be a problem if someone has cut off or dug out the dome alignment nubs (as has been done to yours).

@Bruce Palmer Can describe the process necessary to align the domes (and hence the needles to the nozzles), but remember that each and every time you loosen or remove a dome, you must go through the same alignment procedure again.

Here's your pic with the needle that looks worn:

20180721_143902.jpg

And here's your pic with what looks like a non-round nozzle hole that has been worn by contact with the needle:

20180721_141927.jpg

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I've realized after working on a few and participating in a bunch of "help me with my carbs" threads, one of the easiest and most notable problems is the position of the the float hanger and the metal tang that the needle rides on.  Mine was like yours, bent all to hell to get the valves opening and closing with the lids turned upside down.  That was the old way to set them when they had Grose Valves.  The newer style that has the small needle like pin will not hold the weight of the floats so you can not set them the way they show in the Z Therapy Just SUs DVD.  It took me a year to figure that out.

Your floats should look like this, the hanger should be parallel with the float's top and the tang should look like a bump not a ramp.  Your floats are closing the valve too soon causing low fuel in the float chamber.

Disregard the red circle

Image result for set floats siteunseen classiczcars.com

image.png

 

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Here's good picture Zkars or Jarvo put up showing a way to measure the fuel level 23mm down from the underside of the lid.  It's the easiest way I found to get in the ballpark.

IMG_1006.jpg

 

 Another thing I would suggest while you are getting the levels set is to stick the cork gaskets onto the lids with fuel proof black RTV.  A thin layer on the lids then lay the gaskets down and then lightly screw them back down to the float chambers while the RTV sets up.  You'll be able to remove them without damaging the cork gaskets.  Makes getting them back on a heck of a lot easier too. ?

20170102_201821.jpg 

Edited by siteunseen
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Waiting on parts to fix some items. I have tried to call Ztherapy several times are they still doing carbs? I spoke with Bruce and he told me to call Steve and no answer? The number Bruce gave me just rings for a few minutes.  

I will see when I receive the gasket for the float and adjust the float if that works for me. 

I went by a Mechanics shop who works on antiques. A lot of euros and he was telling me to clean the needle with 1k sand paper clean it up a little? Anything on this? 

Thanks again,

Chris

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Never heard of having to clean the needles


72 body with 71 interior, Eibach, Illumina, R180 CLSD, 83 close ratio, 3.90 gears, Zstory, SUs, BRE Libre wheels and front spoiler.

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3 hours ago, NA&CH said:

I went by a Mechanics shop who works on antiques. A lot of euros and he was telling me to clean the needle with 1k sand paper clean it up a little? Anything on this?

Using sandpaper to remove even more material from needles that already have unintentional material removed from them probably isn't going to help.

To be honest, I'm a little lost on exactly what problem it is that your are chasing... Can you restate the problem you are trying to fix? Maybe a fresh start will help.

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@Captain Obvious I purchased the z with a "msa" header and straight 3" bent metal... car was obnoxiously loud. Car ran and drove perfectly fine. 45min cruises no issues at all in FL. I did have always a half to full tank. I never really got into the throttle say to redline yo see if I had any sputter or missing of sorts. The car was to loud. But this issue would have definitely been felt. 

I purchased a Zstory exhaust and had that installed. Changed nothing else besides the exhaust. When the car returned i took the car out for a test sound drive. First to second then i roll into the throttle once i got past 4k the car started to sputter and would shut down the tech would jump fuller redline to 0 back to rpm. Then idle fine. I u-turn do the same thing and the c Ir shuts off and does not turn over. Eventually when cooked down it started up idled ok. The car had a 1/4 or lower. Closer to 1/8 tank. I then replaced the gas filter after the fuel pumps out back. 

I drove into the carb cleaning and now cant di anything until my gasket arrives. 

Vacuum seemed fine; compression 170-180 across the board. 

I did notice before pulling the front carb off that when I would blip throttle there was no suction. I adjust the mixture screw(behind dashpot by connector rod) before I knew the adjustment screw below. Never did do a test drive before the gasket broke on the float tank. 

Mechanic also said the float angle was way off. 

Hope this helps helping me @Captain Obvious

Thank you all for the help,

Chris

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I emailed Ztherapy. The carbs are theirs from 04. I was seeing if they had anything new done or just another rebuild in the future.  Spoke with Pam. 

 

Chris 

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On ‎7‎/‎27‎/‎2018 at 5:58 PM, NA&CH said:

i took the car out for a test sound drive. First to second then i roll into the throttle once i got past 4k the car started to sputter and would shut down the tech would jump fuller redline to 0 back to rpm. Then idle fine. I u-turn do the same thing and the c Ir shuts off and does not turn over. Eventually when cooked down it started up idled ok.

If the tach is jumping around when the problem is occurring, then the problem is electrical in origin (ignition), and has nothing to do with the carbs.

It unfortunately sounds like you may have created some more work for yourself by diving into the carbs. Don't get me wrong though... I wouldn't be surprised at all if there were some gains to be had by working on the carbs, but it sounds like the main problem that got you here looking for help in the first place has nothing to do with the carbs.

And, also unfortunately, the carbs are like genies in the bottle. And you've let at least one of them out.  Now you've got torn gaskets, misaligned needles, at least one malfunctioning suction piston damper, and unbalanced carbs.  I'm so cheery to have around, aren't I?    LOL

Don't worry. There are lots of people here on the forum who won't rest until you're back on the road. When you get your new gaskets, try to get everything back together and see what happens. Have you ever measured the float bowl level?

Did @Bruce Palmer ever get in touch with you to help you with the needle alignment requirements?

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On 7/26/2018 at 7:09 PM, Captain Obvious said:

Using sandpaper to remove even more material from needles that already have unintentional material removed from them probably isn't going to help.

To be honest, I'm a little lost on exactly what problem it is that your are chasing... Can you restate the problem you are trying to fix? Maybe a fresh start will help.

Looks like the pitting is at stations 1 & 2 which are in the idling zone.  Polishing the needles only in this area will make it richer at idle which will foul the plugs unless the mix nuts are raised, and that will make it too lean at cruise and top end. According to the "Just SUs" book (and common sense), modified needles must have an even taper.

According to official SU publications, modified engines (they include engines with only a change to air cleaners or exhaust system) require non-stock needles. The publications refer to British SU's for which there are a variety of needles to choose from. Nissan didn't supply alternate needles for the Hitachi's as far as I know. Modifying needles is easy enough I guess for Z car engine builders and race mechanics (I saw one with 40 years experience leave with stock needles and bring them back 5 minutes later after modifying them) but for me it's an all day job, with lots of note-taking and micrometer measurements, followed by road tests, and it's still a bit iffy.

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@Captain Obvious nothing from ztherapy. I called and spoke with @Bruce Palmer and he told me to call Steve. The number for Steve just rings. Oh well. 

I am lost. I received the gaskets for the float bowl. Installed and no leaks. Also no fuel flowing from the velocity stack. So 1 thing I think may be fixed. The level. I'll have to check that. I blew into the fuel line and played with the float bracket so it would be parallel with the top. All items work here. The pin there is no leak or something stuck. 

I did notice nothing changes when I take the vacuum hose off of the distributor. I also read try blowing into the distributor through the hose. Nothing moves and the engine does not change idle, die nothing. 

The car will not start with 2.5 turns down from the adjustment screw. I had to go to 4 turns to get it to start and idle. 

I feel the car is working on the back 3 and that is all. I have in my possession a flame thrower 1.5ohm and the electronic spark parts. Should I change those out and then start playing with the carbs?  

I also purchased a new balance bar bc my OEM one was missing the spring screw on the front carb side. Originally zip tied together. And looks like the new one with the screw is no different. I am missing something here. 

Anyone want to sell me a Just SU video? I am looking for the white towel emoji.... 

Thanks all again,

Chris

Oh and I have something pulling power enough to kill off a brand new optima redtop battery....

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If it was only running on three cylinders you'd probably know it.  Although, apparently, three cylinders are almost as smooth as six.  But that would be half power.

The ignition parts probably won't help what you're describing.  And the distributor vacuum is probably on ported vacuum so nothing will happen at idle if you disconnect the hose.  And you would suck on the hose, not blow on it, for a test.

You might start over with a new description of what's happening now.  You started with what sounded like a possible ignition problem, then you got in to the carbs.  Not 100% clear what problem you're trying to solve. Might be blending two or more together.

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I would change as little as possible and work on one thing at a time. Don't put in any other significant parts (like a new coil) until you have a handle on where you are now.

Someone please lend this guy a copy of the just SU video? 

Any kind member in the Naples, FLA area that can lend a hand?

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Going down 4 screws in order to get a start is an indication that the float level is out of adjustment. Although you have set the parallel adjustment, the middle lever should be adjusted too. From the top portion above the float (not the lip, rather the plane that makes the edge) set the distance to close at 14mm, I do this by blowing air into the float needles, and adjusting the float till I hit the point, measure, and adjust.

Once you have this established you should be able to get the tune back to being around that 2.5 screws down.

We’re are you located, maybe there is someone around that can give a hand.


Sent from my iPhone using Classic Zcar Club mobile

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6 hours ago, heyitsrama said:

Going down 4 screws in order to get a start is an indication that the float level is out of adjustment.

That's too general. There are lots of things that could cause a necessity to run four turns down.

And now that the floats have been "rough set" using mechanical means, the only way to truly be sure the level is correct is with a clear tube to actually view the bowl level. Everything else is just a guess.

6 hours ago, heyitsrama said:

We’re are you located, maybe there is someone around that can give a hand.

I think that would be the best thing... His location is near Naples, FLA.

It would be great if there was a kind forum member not too far from there who was willing to stop by and lend a hand!

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Thanks a bunch for the ideas and tips guys. I have my auto mechanic(electrical) going to search the power pull this weekend.

One of the very first comments was that the electronic parts I had could by my issue. I know I opened a "can of worms" with the carbs but if there is not enough spark getting to the sngine could that cause anything with the carbs? Typing this and reading  makes believe I know that answer... Just typing out loud.

I'll look up float bowl adjustment. And check things off...

Any YouTube watches I should look at? 

Chris

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If your original issue was the engine cutting off and the tach dropped to zero when it happened, then the main issue isn't (wasn't) the carbs.

Someone's got to have good pics of using the clear tube to measure the bowl level. Anybody got a handle on some good pics or videos?

I'll ask again for someone out there to loan out a copy of the Just SU's video... Anyone?

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3 hours ago, NA&CH said:

 I have my auto mechanic(electrical) going to search the power pull this weekend.

One of the very first comments was that the electronic parts I had could by my issue.

What do you mean by "electronic parts"?  The ignition system?  And do you mean the stalling issue or the power drain issue?  Sorry, you kind of ran a bunch of things together.

What is the current status of the car?  Does it run and drive?  Maybe restate the problem as it is today.

 

 

 

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