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  1. #26
    FEP Super Member xctasy's Avatar
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    Saul Goode, my man!


    Power valves exist when a carb is not "one venturi per cylinder". On a Ford SOHC four, the need for a power valve drops off as hp rises. Its got such a good potential draw from the 2-bbl intake that it could behave like a 180 degree manifold like the old Lynx 180 manifold for DellOrtos DHLA and Weber DCOE



    http://i.ebayimg.com/images/g/HbIAAM...1N/s-l1600.jpg

    On a 2-bbl V8, it needs progressively more power valve CR as the engine gets bigger, more cammed, or hopped up. The wetted perimeter of the V8 intkae manifold requires more gasoline. A little 2-bbl 4 cyl, not much at all. 2.3 OMC D-port intake, the Esslinger aluminum head intake, al start behaving like independent runner intakes


    I can put a Weber DCNF 40 2-bbl used for an independent runner V6, V8 or V12 Ferrari on to a 2000 or 2300 and get the best power curve possiable. A power valve is a crutch for an intermediate ciruit.

    A holley well tube emulsifies air at certian points, and depending on what you do to it, positions of the holes and the amount of fuel the power valve exudes can cause tunning problems by over fueling when vac drops. You can play off jetting, power valve Hg, and the effective power valve channel size by doing other stuff, but the best option is to find what idela PVCR suits your engine size. The 17 would be idlea for a 121 to 140 cube engine, 59 a 2-bbl 390. A 2-bbl 250 works with a 59 PVCR, but would be much better with 40's.



    Your 231 WITH 500 cfm 4412 would probalby work best with 40's.

  2. #27

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    Quote Originally Posted by xctasy View Post
    Saul Goode, my man!


    Power valves exist when a carb is not "one venturi per cylinder". On a Ford SOHC four, the need for a power valve drops off as hp rises. Its got such a good potential draw from the 2-bbl intake that it could behave like a 180 degree manifold like the old Lynx 180 manifold for DellOrtos DHLA and Weber DCOE



    http://i.ebayimg.com/images/g/HbIAAM...1N/s-l1600.jpg

    On a 2-bbl V8, it needs progressively more power valve CR as the engine gets bigger, more cammed, or hopped up. The wetted perimeter of the V8 intkae manifold requires more gasoline. A little 2-bbl 4 cyl, not much at all. 2.3 OMC D-port intake, the Esslinger aluminum head intake, al start behaving like independent runner intakes


    I can put a Weber DCNF 40 2-bbl used for an independent runner V6, V8 or V12 Ferrari on to a 2000 or 2300 and get the best power curve possiable. A power valve is a crutch for an intermediate ciruit.

    A holley well tube emulsifies air at certian points, and depending on what you do to it, positions of the holes and the amount of fuel the power valve exudes can cause tunning problems by over fueling when vac drops. You can play off jetting, power valve Hg, and the effective power valve channel size by doing other stuff, but the best option is to find what idela PVCR suits your engine size. The 17 would be idlea for a 121 to 140 cube engine, 59 a 2-bbl 390. A 2-bbl 250 works with a 59 PVCR, but would be much better with 40's.



    Your 231 WITH 500 cfm 4412 would probalby work best with 40's.
    All I'm saying is that Ø0.017" PVCR's will be ideal IF that's what them and the jetting works out to be what the engine likes.

    With my 231, with the 500cfm 4412 that's on it, I haven't had much opportunity for wringing it out on the street, but I can say for certain, as it is right now, with idle feed restrictions reduced to Ø0.027" from Ø0.036", #68 main jets (factory jets were #73's) in it, and the total fuel flow area relationship from Holley kept, with Ø0.073" PVCR's (factory PVCR's were Ø0.062"), it's running pretty good. It's pretty darn close to ideal, besides more in-depth WOT tuning. With how it's presently working, I don't imagine having to reduce the PVCR's down into the 40's, though if that's how it turns out they may very well end up there. We'll see. The plugs are clean and have a tan-ish/grey color to them, though as per most factory specified spark plugs, they, and somewhat the way the car runs, do show signs of being too hot, and I'll be installing some cooler Champion RS10LC's in place of the original RS14LC's. There hasn't been any black clouds behind me, or any erratic too-rich indications in how it runs when acceleration has dropped the manifold vacuum below the opening point (8.5"Hg) of the power valve, and during some WOT blasts. The WOT blasts up the tach have been smooth and... brisk... on par with it not being a powerhouse in any stretch of that word, though far and away better than when still stifled with the CFI, lol. So yes, without wide-band tuning ability, or more WOT opportunity and tuning, I can't be absolutely certain. With no signs yet of lean surging anywhere above (or below) PVCR augmentation, there's more fuel trimming yet in the low-speed and cruise areas. I'll get there, and then with the WOT mixture dialing in.
    Last edited by Walking-Tall; 08-28-2016 at 05:00 PM.
    Mike
    1986 Mustang convertible ---> BUILD THREAD
    Past Fox-chassis "four eyes":
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1980 Capri RS Turbo

    Work in progress website ---> http://carb-rebuilds-plus.boards.net/

  3. #28
    FEP Super Member xctasy's Avatar
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    The Holley references always says when you jet down to suit another application, you have to maintain the total jetting and look at the Power Valve channel restrictions in terms of total fuel requirments. That is for similar applications where you have to add lib it to suit a new target hp or capacity size. Like if you stroke your 5.0, or put a 2300 Holley on a 255 or 231. Then you would jet down, and leave the power valve, and only reduce it if you air fuel ratios didn't suit the engine on a dyno.

    That's okay if its the same kind of engine, but not if its a much smaller engine. Then you have to work out the fuel delivery on a dyno and adjust if you can't get the right numbers.


    How you adjust it is up to you, but on my Cortina 2000 and 2300's, the channel restrictions are too big with any V8 2-bbl. If you kept the PVCR the same, and jetted down the mains, then you'd be pig rich on the wide open throttle. The power valve is just there to spike early fuel delivery to get the air fuel ratio right. If there are problems with over supply, start lean as per the SOHC Pinto recomendations, and go up. You can predrill the PVCR plugs, and adjust.

    I've seen the pintel rework, and spring changes to the power valve on Holley Webers and traditional 4150 and 2300 series carbs, and I guess if it works, good on you. I just can't see how it can postively behave better than the way the designers configured it.

  4. #29

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    I just scored one of these "350" cfm Holley 2-barrels for a song... https://www.ebay.ca/itm/Holley-7448-...53.m2749.l2649

    ... and will fix it's factory-instilled (for apparent race duty) idiocies and try it on the 3.8L V6 to see if there's any merit at all to the "that carb is too big" business... stay tuned...
    Mike
    1986 Mustang convertible ---> BUILD THREAD
    Past Fox-chassis "four eyes":
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1980 Capri RS Turbo

    Work in progress website ---> http://carb-rebuilds-plus.boards.net/

  5. #30
    FEP Super Member xctasy's Avatar
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    On all six cylinder engines, the Holley 350 likes 65 jets and 6.5 power valves with no reduction in PVCR's.

    The standard go to carb for 202 Holdens and 250 Falcon 2V's. On Hemi 245's and 265's, they out perform 318 LA Mopars, so a 1.33" 424 cfm Autolite like you had always works well. 350's are too small (1.1875" venturi), and 500cfm's, (1.375" venturi) j-u-s-t right.

    A 650 Holley 4-bbl works best on a 245/250/265 six with a big cam. Big cams with 280 degrees at lash and 220 degres at 50 thou and big 424-500 cfm 2-bbls often hate each other, as reversion can happen. But lobe center can calm or make it worse, and retarding or advancing and lifter lash if solid are you other tuning options. Attempting a four corner idle isn't a waste of time. On 2-bbls, you go right to well tubes if you have idle problems, and play with the emusification by adding or deleting a 25 thou hole, just like Ford did on the Autolites K cluster.

    I'm not sure which one I'd try first.

    All the V6's seam to have a much nicer intake with a direct shot, and less of the part throttle to wide open throttle air fuel ratio variance. In line sixes can be the worst to tune. They honk (um, the go really strongly with one), but don't ever idel nice. The Holley 350 cfm is always seen as a 289 or 318 or 283/305/307/327 Econo carb, but on V6's and I6's, people see it as being too big.

    I love it. It always makes good power, and its dial in always seasm to be about 135 to 155 hp, and it gives okay fuel economy.

    I have seen how you work, you have a different kind of logic that isn't fuzzy. I like it. It's the Holley Performance Manual Brain in head method.

    Dave Emanuel would be proud of ya!.

    (He would be about 71 years old now, his last book was "How to Rebuild and Modify Carter/Edelbrock Carburetors" – May 9, 2007)

  6. #31

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    I attribute most of the "smarts" I might think I have today, and what's been instilled in me, to the man who helped put Ferret Industries from small town Hanover, Ontario, Canada, onto the map with championships in the 70's and on into the 80's and 90's in Formula Ford, my father. I got a championship t-shirt in '79, and as a lad of only 11 years old, that was pretty cool knowing your dad was part of something that kicked a$$... though not enough to overshadow all he'd accomplished and taught us prior and afterward about all of this automotive stuff... in a nutshell, cut through the BS, eliminate any unnecessary variables, and always make sure the basics are sound... which always equals "running like a clock". If still with us, he'd be 71 this year as well.

    As to this smaller 2-barrel that's coming, I'll clean it up and go through it, see what makes them tick, maybe try it on the car, or sell it to a local racer that's required to run those... we'll see...
    Mike
    1986 Mustang convertible ---> BUILD THREAD
    Past Fox-chassis "four eyes":
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1980 Capri RS Turbo

    Work in progress website ---> http://carb-rebuilds-plus.boards.net/

  7. #32

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    There is no one size or calibration that fits all. The well tubes that WERE in this thing's main wells haven't anything to do with idle, but are "emulsification" condition/variances of the main circuit, with four 0.024" cross drilled holes through each tube, @ about 1/16" above and below float level, for a total of eight holes per tube... factory or modified, equaling about three times as much area as is usual in old school Holley carburetors. The evidence (brown and black gaskets, stuck like a beeotch, and ancient round holes power valve) is that I'm the first one inside this thing after 40 years. The idle circuit variables, that would likely be too rich for even most race situations, in this is another story I'll get to later...

    Like most all that is newfangled pretty and expensive, this small "race" carburetor, as is, would probably suffer the same shortcomings of comparatively rich down low and through the middle and go leaner up high, with the equivalent of 'e-bleeds gone wild' syndrome in some of the newfangled pretties. Too big or too many "emulsion" bleeds does nothing but encourage fueling to be rpm-dependent instead of load-dependent, with earlier lower rpm and airflow main circuit fueling, and hinders upper rpm and airflow main circuit fueling (inconsistently puking blobs of fuel doing so), the opposite of what is necessary for fuel efficiency and most (safe) power. Jetting such new fancy contraptions for best (and safe) upper rpm WOT air:fuel ratio results in low and mid range rpm being rich, a WOT fuel "curve" (that shouldn't be a curve at all) that starts out rich and progresses lean, the worst of both worlds. The 100 year old solidly established physics of precise function, and the original engineered and designed and spent on for millions of 1950's and 1960's automobiles, two per barrel "e-bleeds" in the air wells, angled into the main wells, usually sized 0.026-0.028", exist in that quantity and in those sizes and locations to provide a consistent main circuit WOT air:fuel ratio across the widest rpm range bottom to top. Anything else more recent that costs an arm and leg has frequently enough been proven to be the reinvention of the wheel, prettier, and with half as many spokes, making for a bumpy ride and soon to be broken wheel, so to speak.






    Here are it's major parts disassembled for examining and for measuring and recording all of it's circuit calibrations:

    All (air bleeds - main air bleeds inner, idle air bleeds outer) looking untouched and in order up here:




    Uh oh, I don't like the look of these holes in the body bores that exist in the path between the idle mixture screws and the normal idle discharge ports in the base plate:






    Uh oh, I don't like the look of these (feed) holes below (the base plate is bottom side up) the transfer slots. These and the holes shown above should basically render the idle mixture screws useless:




    Original metering block, with main well tubes and idle feed restrictions removed:




    Hmmm, kill bleeds (into the angled booster feed passages) for straight leg boosters are not normally necessary (but for the increased sensitivity of down leg boosters), and upper main well bleeds to connect main air bleeds with the main well tubes that were in there:




    Here's how she maps out:




    Changes, whether I use it or for anybody else to use, for sensible efficient function, are a-comin'.

    To be continued...
    Last edited by Walking-Tall; 01-11-2018 at 12:37 AM.
    Mike
    1986 Mustang convertible ---> BUILD THREAD
    Past Fox-chassis "four eyes":
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1980 Capri RS Turbo

    Work in progress website ---> http://carb-rebuilds-plus.boards.net/

  8. #33

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    After pondering the above idle/transition circuit additions/differences from the original circuits, the holes up in the body's bores that are above the idle mixture discharge ports in the base plate can only serve the same purpose as drilling holes in throttle plates does, to add idle air bypass, commonly done with something with a grumpy camshaft. I'd imagine that done in the way that's done within this would have a sizeable (diminished) affect on the sensitivity of the idle mixture screws, the idle manifold vacuum signal to the idle mixture screws (upon disassembly, one idle mixture screw was 1/4 turn out and the other was 2 turns out... neither probably did much of anything in the way of being able to adjust idle air:fuel ratio)... hence the 0.028" idle feeds right below the transfer slots, for idle air:fuel mixture contribution... all of which, IMHO, is a convoluted, unnecessary, likely basically non-adjustable recipe for richness, inside-the-box, one-size-fits-all couple of ways of doing a very simple thing, to allow an engine to idle with the airflow that it wants and with an efficient idle air:fuel ratio that's adjustable to set it at what it wants. That's done simple and effective with the original traditional Holley idle/transition circuit.

    These 7448's are marketed 1st as for the street, and 2nd for racing.

    I beg to differ after opening one up, lol, and wouldn't leave this thing as it was for either scenario or anything in between. If what I'm eliminating and rearranging are manufactured features and not somebody's modifications, I wouldn't recommend a 7448 be bolted onto anything right out of the box. I can see now why the OP of this thread had vaguely described black sooty spark plugs with nothing apparent out of the ordinary... with jetting in question. Plug-fouling rich running in general when running on the idle/transition circuit would be my guess now after dissecting one, with no normal or easy way of tuning it out. Additionally, inconsistent function is just about a guarantee when idle feed restrictions are metering fuel AND air, located above the fuel level up high in or near the top of the idle wells (the guarantee will be inconsistent spurting of idle/transition air:fuel flow, because of the close proximity to the idle air bleeds making it possible for air to also get behind the idle feed restrictions) in an engine (2.3L) where the pulses in the intake tract are probably at least as bad or worse than in a rowdy cammed V8.


    Wordy rant should mostly be over, LOL!


    I tapped lead down into the holes below the level of the bottom of the transfer slots to block the 0.028" idle air:fuel feed holes:




    ... and blocked the holes in the body bores with lengths of 1/8" brass tubing, so that they will no longer infringe upon the simple basic function of the idle mixture screws' adjusted air:fuel amount getting delivered to the idle mixture discharge ports in the base plate:






    I'll put in 0.024" IFR's (idle feed restrictions, in the original low locations (where they belong (NACA 'REPORT No. 49, METERING CHARACTERISTICS OF CARBURETORS.' conclusion: "Submerged fuel metering passages are free from instability and irregularity of discharge when the head is very small."))) and have put (adjustable, 8-32x3/16" brass set screws) idle air bleeds at 0.074" for starters.




    In place of the main well "emulsion" tubes, I'll add 4 (2 per barrel) traditional 0.028" fuel "curve" correction bleeds to the metering block in the original traditional locations. The unnecessary upper main well bleeds and the kill bleeds will be blocked. If the boosters do happen to get flowing too soon due to the small venturi diameter, I'll reopen the kill bleeds.

    OP, where ya been and what did you end up doing?...
    Last edited by Walking-Tall; 01-11-2018 at 01:26 AM.
    Mike
    1986 Mustang convertible ---> BUILD THREAD
    Past Fox-chassis "four eyes":
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1980 Capri RS Turbo

    Work in progress website ---> http://carb-rebuilds-plus.boards.net/

  9. #34

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    I've learned that these don't need any low and mid rpm/flow encouragement to flow too much through the main circuits because of the small venturi size, especially if flowing near sonic on a race engine of some form... when jetted properly for high rpm WOT the low and mid range usually ends up being too rich (like newer incarnations with too big and too many "emulsion" bleeds), so only the new upper e-holes will have restrictions in them. We'll see how she works...




    Decent starting point 0.024" idle feed restrictions...





    Added a full manifold vacuum hose tube up front where there is a boss for one, but the "race" base plate didn't have...




    The factory size needle and seat, main jets, PVCR's, and main air bleeds stay as is, unless and until deemed necessary to change when this 2-holer gets bolted down where it's gonna run, again, especially if goin' racing.
    Mike
    1986 Mustang convertible ---> BUILD THREAD
    Past Fox-chassis "four eyes":
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1980 Capri RS Turbo

    Work in progress website ---> http://carb-rebuilds-plus.boards.net/

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