Results 1 to 17 of 17

Thread: '72 SU Float Level

  1. #1
    Registered User landmizzle's Avatar
    Member ID
    CZCC-4054
    Join Date
    Apr 2003
    Location
    Modesto,CA
    Age
    54
    Posts
    129

    Default '72 SU Float Level

    Hi all,

    I'm still dealing with a high rpm issue, but I'll leave that to another thread.

    What I would like to know is the float level for 1972 carbs; I hear that they are not the same front and rear. I believe the typical level ('70 and '71) is 23 mm measured from the bottom of the lid to the fuel level with the floats in the fuel bowl.

    Measuring from bottom of lid to fuel level (using clear plastic hose from fuel drain and aligning it up against side of bowl.) I can get a level of 1 inch (25.4 mm) pretty easily for both carbs. Is this close enough?

    I'm getting pretty good with the whole procedure, but it's still fairly time consuming. Unfortunately, so far, all my attempts to reduce the fuel level a few millimeters results in the level going too high and gas overflowing. If an inch is good enough, I would rather move onto other issues to trouble-shot my high rpm hesitation issue. It feels like I'm chasing a phantom goose trying to get get that last 2 mm precision. Is the fuel level that finicky?

  2. #2
    Registered User
    Member ID
    CZCC-2139
    Join Date
    May 2002
    Location
    Salem Or
    Posts
    1,556

    Default

    We've spoken
    Bruce Palmer
    Salem Or
    Sales@ztherapy.com
    www.ztherapy.com
    503-587-9800

  3. #3
    Registered User zdogg's Avatar
    Member ID
    CZCC-26095
    Join Date
    Jan 2012
    Location
    calgary alberta canada
    Posts
    22

    Default

    Give Bruce a call and get the Just SU video from z therapy it make things so much easier.......I know first hand

  4. #4
    Registered User
    Member ID
    CZCC-25653
    Join Date
    Nov 2011
    Location
    nor cal
    Posts
    2

    Default

    flip the float over and do a 1/8 gap. go rich on your A/F mix then then crank it back to lean it out

  5. #5
    Registered User
    Member ID
    CZCC-27135
    Join Date
    May 2012
    Location
    Sacramento, CA
    Age
    71
    Posts
    20

    Default

    Don't have an answer but am working on the same thing. I have Bruce's dvd, but there seems to be a flaw
    in using a gage like he does. I machined a gage, my bowls over-flowed. I ended up machining a barb fitting
    that goes in the drain hole (like Bruce sells) and used a plastic tube. I've found it is a "cut and try" process,
    when I had the level right, the gap between the rim of the lid and top of the float wasn't anything near the
    .55". I just bent things to make the 23mm of fuel level to come out right. Took several times.

    I also found that often the float would hang up on the sides of the bowl. I took the over-flow barb off and
    inserted a small piece of wire to make sure the float was free and not catching. I couldn't figure why my bending
    of the tab wasn't changing the level, the float was sticking on something. Now I keep the four screws loose,
    wiggle the lid until I know it is free then tighten the screws.

    Finished one carb tonight, will finish the second one tomorrow. I bought new bowl valves from Bruce, but they aren't
    the ones like in the video with the balls. I have to wonder if that's why my measurement of the bowl height is different,
    did he change valves?

    Incidentally, I'm using Tygon F4040 fuel line, gasoline proof. Clear and very flexible.

    Jim

  6. #6
    Registered User
    Member ID
    CZCC-2139
    Join Date
    May 2002
    Location
    Salem Or
    Posts
    1,556

    Default

    The flaw is that the video Scott did way back when, used the Grose Jets which are no longer available. The needles and seats need the lid to be held with the float hanging down. blow lightly into the fuel inlet tube while moving the float toward the lid. When the needle closes you can feel it and that is where you meaure from the bottom of the flloat bown lid to the float. I've been bugging Steve and Pam to re-do that section of the video for years with out success.

    Inverting like the video shows, automatically will over power the little spring in the needles and seat giving an incorrect float level setting.... Any one waqnt to chat about any of this, I'm just a phone call away.....
    Bruce Palmer
    Salem Or
    Sales@ztherapy.com
    www.ztherapy.com
    503-587-9800

  7. #7
    Registered User
    Member ID
    CZCC-27135
    Join Date
    May 2012
    Location
    Sacramento, CA
    Age
    71
    Posts
    20

    Default

    That's funny Bruce, that's exactly what I ended up doing, the bowl lid in the normal position,
    while I blew into the inlet, I slowly raised the float. I held a metric machinist's scale next to
    the float, when the flow stopped, I read the number. I can't 100% agree with your number
    of .55" (about 14mm), I'm getting closer to 18mm, but I'm confirming my final measurement
    with a site glass (tube). I think your .55" is accurate, IF the same Grose jet had been used,
    but that's not the case now.

    Most important, we are all on the same page.

    Jim

  8. #8
    Registered User
    Member ID
    CZCC-2139
    Join Date
    May 2002
    Location
    Salem Or
    Posts
    1,556

    Default

    I think the measurements to the top of the float or the top of the fuel should all be equated to where one's happiness setting on the fuel nozzles are. When all is said and done and the nozzles are where ya like 'em, the fuel level as viewed down in the nozzle should be about a sixteenth of an inch below the top of the nozzle. Puddling up on top of the nozzle things'll be fat and contrary to that if the fuel level is too far down the nozzle things'll be lean. That is what all the jumping around is about.... where the fuel level is in relation to the top of the brass fuel nozzle.....

    Just putting this out there as crib notes for any and all looking over our shoulders.....
    Bruce Palmer
    Salem Or
    Sales@ztherapy.com
    www.ztherapy.com
    503-587-9800

  9. #9
    Registered User Gary in NJ's Avatar
    Member ID
    CZCC-21253
    Join Date
    Mar 2010
    Location
    Amongst the twisty roads
    Posts
    1,057

    Default

    Quote Originally Posted by Bruce Palmer View Post
    I've been bugging Steve and Pam to re-do that section of the video for years with out success.
    Just a suggestion but when and if you do re-shoot that section, I would post a clip here on this website. Many of us on this site have purchased the DVD and it would be helpful to have the correct footage.
    Gary
    Guardian of HLS30-91415
    Previous Owner of a 10/70 240Z ('83-'85)

  10. #10
    Registered User Jeff G 78's Avatar
    Member ID
    CZCC-7975
    Join Date
    Mar 2005
    Location
    Northville, Michigan
    Age
    53
    Posts
    1,895

    Default

    I bought the VHS tape back in the 90's when Scott ran the business and it's barely viewable anymore even though I've only watched it a few times. With enough tries, I can usually get the tracking in line so I have some sort of picture and sound.
    Jeff
    Northville, Michigan
    IZCC #1285
    '78 280 10:1 CR, Arizona Z Car header, urethane bushings, Tokico springs, Illumina struts, Panasports w/Hankook R-S2 225/50R16 tires, Maxima 105 amp alternator
    http://www.classiczcars.com/photopos...00&ppuser=7975
    '74 260Z BRE look-alike crap can for Optima Batteries ChumpCar World Series Racing racing
    https://www.facebook.com/Jeff.Grauer

  11. #11
    Registered User
    Member ID
    CZCC-18523
    Join Date
    Jan 2009
    Location
    Texas
    Posts
    25

    Default

    Hate to dig up an old thread (but the last post is only 6 weeks ago), but I am still looking for a clear answer. Is the 23mm down from the lid the starting measurement for ALL the round-tops? I have a '72 set with the different length float hangers and want to be sure I get the correct starting point. The car is running now, but I am going back and fine tuning the carbs.

    I have a second issue that I have not been able to find any info on; when the car has been driven then parked for 15-30 minutes, when trying to re-start, I have to give it some throttle to get it to fire. I have double checked to be sure the choke is not causing the problem. I am thinking it is a heat-soak issue, but not sure how to resolve it. I do have the heat shield in place, and am running headers, so wondering if the heat shield needs to be changed/enlarged to better protect the float bowls. Any thoughts?

    Thanks!
    Bryan

  12. #12
    Registered User
    Member ID
    CZCC-2139
    Join Date
    May 2002
    Location
    Salem Or
    Posts
    1,556

    Default

    Headers, in Texas, in the summer...... Sounds like triple dipping to me. When you think you are facing that situation try pulling the choke on just a tick and see what that does. Not too much but just a bit to see if richening things up just to get started will help.
    Bruce Palmer
    Salem Or
    Sales@ztherapy.com
    www.ztherapy.com
    503-587-9800

  13. #13
    Registered User
    Member ID
    CZCC-18523
    Join Date
    Jan 2009
    Location
    Texas
    Posts
    25

    Default

    Thanks Bruce, I will try that next outing. What about the float levels between the two bowls with different length stand-offs? Set them both the same at 23mm?

  14. #14
    Registered User
    Member ID
    CZCC-2139
    Join Date
    May 2002
    Location
    Salem Or
    Posts
    1,556

    Default

    Yes, there is only one length needle and seat that I know of so bend the tangs to accomodate the difference..... I can't tell you why that was done in the first place nor can I say which went where...... It's out and out bafflement!!
    Bruce Palmer
    Salem Or
    Sales@ztherapy.com
    www.ztherapy.com
    503-587-9800

  15. #15
    Registered User
    Member ID
    CZCC-18523
    Join Date
    Jan 2009
    Location
    Texas
    Posts
    25

    Default

    Quote Originally Posted by Bruce Palmer View Post
    Yes, there is only one length needle and seat that I know of .....
    Interesting, I will check the carbs and the rebuild kits I used for them. I am pretty sure there are two different length needle and seats.

    Thanks!
    Bryan

  16. #16
    Registered User
    Member ID
    CZCC-18523
    Join Date
    Jan 2009
    Location
    Texas
    Posts
    25

    Default

    Well, have been out of town on vacation the last week, so did not get back to the Z yet. I did check the carb kit boxes for the needle/seat assemblies that were removed when I rebuilt them. One measures 13/16 in length, the other measures 3/4 inch in length. The carb kits have different part numbers also with all parts being the same except the needle/seats. I have not made time to pull the tops off the float bowls to check the installed needles, but remember them being the same as in the kits. Also have not driven it recently to try adding a bit of choke when hot to see if that helps.

  17. #17
    old Z lover
    Member ID
    CZCC-13407
    Join Date
    Nov 2006
    Location
    ST. AUGUSTINE, FL
    Posts
    22

    Default

    Are you still having a problem getting the right level on the carbs? I have fix that has worked for years. Install a boat gas priming bulb (about $5 at car stores) in the gas line supplying the fuel pump. Pump it several times to pressurize the system. You'll have to install clear plastic lines on the drain plugs but you'll get the level and you can record and adjust accordingly. Just leave the bulb installed until you get it running right.

    Let me know if you have questions and how you like the suggestion.

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Setting Fuel Level
    By Blue in forum SU Carb Technical Articles
    Replies: 14
    Last Post: 06-21-2014, 08:18 AM
  2. Gas Depth in Float bowl, when excluding float volume
    By hogie in forum Carburetors (S30)
    Replies: 36
    Last Post: 05-14-2010, 03:08 PM
  3. Fuel level on and off
    By CuadroS in forum Help Me !!
    Replies: 0
    Last Post: 09-22-2009, 06:59 PM
  4. Float level waaay off!
    By vling in forum Help Me !!
    Replies: 6
    Last Post: 08-17-2009, 02:40 PM
  5. 240Z AT Oil Level
    By Bud111 in forum Suspension and Steering (S30)
    Replies: 1
    Last Post: 04-02-2004, 01:33 PM

Bookmarks

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •