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Which Weber carb?

Discussion in '40- & 55-Series Tech' started by Design311, Feb 6, 2003.

  1. Design311

    Design311

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    Which Weber carb is best for an F engine? I have an HEI distributor and a header installed already. Which one is the one for me: 38/38 or 32/36? If it's the 32/36 then is JTO the cheapest place to buy it? They have a complete kit for the Cruiser. Just wanna pay the least I can for it...I'm a cheap ass! :D

    http://jtoutfitters.zoovy.com/product/WEBK743
    http://jtoutfitters.zoovy.com/product/WEBK74338
     
  2. Slowerthanu

    Slowerthanu SILVER Star

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    I would do the 38/38, Thats what I have on my otherwise stock 2F with over 200,000 miles on the ticker.
     
  3. toddslater

    toddslater SILVER Star

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    Design,
    Looking at what JT Outfitters (and all other LC weber purveyors) calls a complete kit is somewhat misleading. Apparently, no one told these folks that they need to be selling Fuel Pressure Reglators to go with these "complete" kits. Buy one and set it at 2.5 to 3.0 lbs. of pressure. Price seems pretty good. As far as which one...in our ultra high performance (kidding here) tractors, you probably couldn't tell the difference. That being said, I'll give you the theoretical better choice.

    Using a CFM calculator, I came up with the figure that our little beauties would need up to ~304 CFM (max) to get them to spin at 4,000 rpm. And dare I say ~380 CFM at 5,000 rpm. If this was a NASCAR cruiser, heaven forbid, that could spin all day at 5,000 rpm then by all means yes to the 38/38 or 390 CFM weber. Since I doubt that this would be the case and quite possibly 98% of your engine spinning should be at or well below the 4,000 rpm range, the 32/36 or 300 CFM would be more of an "ideal" fit. As I mentioned above in our tractor motored Cruisers you probably won't notice the diff.

    What is true and I have notice of motors that are less "tractor like" is that if you are over carburatted, you will lose low end torque and throttle response.
     
  4. LT

    LT

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    How much does the fuel regulator help?? On my 76 I have a 38/38 weber carb, header, and h.e.i. distributor, and it gets s***tier gas milage than my 78 engine that had a weber 38/38 and everything else was stock.
     
  5. Chef

    Chef

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    On the f engine I like the 32/36, it's progressive, more than enough fuel, and it'll get better mileage for being progressive. On the 38/38 getting crappy mileage, the regulator won't really help much. Webers like to see 2-3 psi, so it's a good thing to do, but unless you overpowering the needle and set it will make a pretty minimal diff. I get about 11mpg on my weber 38/38 rig with header, ignition, and head shaved .080 for more compression. If you want (better but not good:)mileage get an aisin 2bbl...
     
  6. LT

    LT

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    i thought about the asian 2 barrel, where do you acquire one?? I've heard that they do just as well off road or even better than the weber.
     
  7. toddslater

    toddslater SILVER Star

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    The value of the fuel pressure regulator is porportional to the age of the carb in relation to the pressure it has seen and is currently seeing. I don't know what the pressure is from a stock f or 2f fuel pump (I'd guess ~7lb.) I suppose I could slap my gauge on it and see. None the less, what will happen is your brand spakin new weber will probably work fine (unless you have some god awful monster elec pump like for fuel injection) for a while, then in time you'll over power the needle/seat/float arrangement progressively to the point where it will run a little crappy then like complete s***. If barely at all. Webers are infinitely and easily adjustable, however the first step in the process is to give them what they want....2.5 to 3.0 psi. &nbsp:Do this then we can take it from there.
     
  8. Design311

    Design311

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    The only reason why I'm considering a Weber is b/c the PO did a number on the stock carb linkage. I have twisted bailing wire holding the choke together. The accelerator pump is screwing up badly right now. I just thought it might be more simple to just start all over with a new set up. I may just buy the Weber 32/36 and a regulator and call it good. You can pick up a fuel regulator at almost any auto parts store right? How much do they run these days? Thanks for all your input guys!
     
  9. toddslater

    toddslater SILVER Star

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  10. Design311

    Design311

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    You're talking about this one right?

    [​IMG]

    I think O'Reilly's sells them for like $15. I guess I'll run by there after work and take a look. Thanks for all your input!
     
  11. LT

    LT

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    Where would the fuel pressure regulator hook up to?? I think this may be what i need.
     
  12. plan66

    plan66

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    I run a 32DIR weber I pulled from my old Renault, because, well, I guess maybe I'm a cheap ass too! Sure the fixed venturies are small, but I get great throttle response. The CFM rating is really only important if you spend lots of time at wide open throttle. Probably 95% of the time I dont even open the secondary barrel at all. I have been averaging 14mpg as a daily driver and trail rig for weekends. I haven't driven many other LC's, but I'm pretty happy with the performance.
    Oh, and I don't have a pressure regulator in mine. Actually I never thought I might need it. I 'think' my needle valve is contolling whatever pressure the pump is pushing, but I sure am going to check.
    Mind you, I'd not recommend just finding a weber off anything at the wreckers. Although they are easy to tune to your engine, it helps if you can start in the right ballpark.

    HTH
    Martin
     
  13. Slowerthanu

    Slowerthanu SILVER Star

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    I have that one, When I put it on it made a differance and then began cutting out at full throttle under load real bad, had it set at 3psi and it kept doing it, pulled it off and the truck ran fine. I want to use but when I disassembled the unit I found nothing wrong.

    What could be causing it to make the vehicle do this???
     
  14. toddslater

    toddslater SILVER Star

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    Design,

    Yep that photo is what you need.

    Slower,
    Hmmm....most folks usually have the opposite problem with setting up their webers...I usually hear "runs fine wide open". If I were having this problem on my weber set ups, first thing I'd do is check the pressure/delivery from the fuel pump. Summit sells their brand fuel press gauge pretty cheap. If all is well their, next look would be at the float level adjustment. If it is running fine without the reg...I would think the answer would be in one of these two.
     
  15. toddslater

    toddslater SILVER Star

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    Slower,

    One more thing I just thought of...fuel filter/sediment. Check and or replace your in line filters and just in case you may have sed in your reg, blow it out with air compressor.
     
  16. Halo3

    Halo3

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    Please stand by for two cents from the peanut gallery...

    Something else to keep in mind is that not all fuel pumps are built the same. While they are all bolting up to a 2F engine, diff't brands can actually pump a significantly different amount of fuel. I ran into this problem in my younger days when I was "tweaking" a 302 in an old '65 Ford F100. I'd swapped from a Napa rebuilt fuel pump to an OEM Ford, and then started having problems with the engine running too rich. After months of trying to adjust the carb, an old timer had me throw in a fuel regulator....and...*voila* my problems went away.