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  1. #1

    Default Holley 4180 Observations, Tidbits, & A Vacuum Secondary Tip

    Finally got an opportunity to rebuild a ('84) Fox Mustang 4180 Holley 4 barrel. The Mustang it came off of now has a 460 in it, and no, this carburetor is not going back on that car, but another on the 302 that came out of it. He's got a 750 I built on the 460.



    Observations and tidbits, pretty much in the order of execution:
    1. Owner provided a (unopened) NAPA rebuild kit. All the parts'n'pieces. No air cleaner gasket. Unfriendly black gaskets.
    2. Ford liked wicked adhesive and gaskets, and to pinch-peen the accelerator pump shooter and screw. (neither is necessary)
    3. Nearly took an axe to remove the primary metering block and secondary metering plate. (small flat screw driver, hammer)
    4. I'd yet to meet remnant gasket material and adhesive that stood a chance against the carb cleaner. Now I have.
    5. Count on ample time for manual gasket material and adhesive removal.
    6. The correct stem length vacuum secondary diaphragm is within the NAPA kit. (kit part # 2-5363A)
    7. Kit came with new needles and seats, but also nice new adjusting nuts and lock screws.
    8. Primary anti-tamper idle mixture screw plugs already knocked out.
    9. Removed secondary anti-tamper idle mixture screw plugs. Details not pretty, but effective. Don't even think about drilling these unless you've got carbide tipped drill bits or the equivalent, because these thick hardened plugs will laugh out loud at anything less for drill bits.
    10. Mixture screw settings, including the ones Ford buried out back, uneven/all over the place...

    11. The secondary transition slots are quite long. Set secondary idle screw to 1/4 turn from fully closed, for no sticking in the bores at idle and for zero secondary transfer slot exposure. Set secondary idle mixture screws to 1/2 turn out (3/32" allen wrench), approximating the 0.025" secondary constant idle feeds in most Holleys.




    12. Drilled and tapped for a customary primary idle speed screw location, eliminating idle solenoid from the already crowded area.




    13. Primary idle mixture screws set to 2 turns out. All of them to be final adjusted on the warmed up idling vehicle (3/32" allen wrench) .
    14. Set the primary idle speed screw for approximate square exposure of the primary transition slots.




    16. Reassembled the rest of it like any other, with a light layer of "chap stick" on the gaskets in the absence of non-stick gaskets.


    A tip on how I install vacuum secondary diaphragms for no tears or mishaps:

    Upturn the diaphragm as shown (which positions it's passage and voids accurately onto the housing), set it into/onto the housing, clamp the stem from below so the housing bottom sits on the vice grips (I don't presently have one, but a bench vise works nice for doing this) and the stem stays put. This accurately aligns the screw holes for lid and spring installation without movement/distortion of the diaphragm by the pressure of the opening rate lid spring as the lid is pressed down to install it. Don't forget the check ball if it requires one. Lightly oil the four screws' threads so they don't catch/tear the diaphragm. Set the lid (with it's opening rate spring) on top, slowly/lightly lower it, aligning diaphragm and lid with the screw holes, install the screws.







    Test the unit and your diaphragm installation by holding it upside-down, compress the stem in, hold a thumb over the vacuum passage to block it, release your hold on the stem and verify that the stem stays put. If so, she's good to go.
    Last edited by Walking-Tall; 10-12-2017 at 01:02 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/

  2. #2
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    qikgts's Avatar
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    Thanks for documenting! I like the secondary diaphragm tip!
    '85 GT

  3. #3

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    Did you happen to measure the stem length of the secondary diaphragm? Does it match up to any of these? http://vb.foureyedpride.com/showthre...=1#post1818838

  4. #4
    FEP Super Member erratic50's Avatar
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    Great write up - thank you!

    A person almost wants to make a tech write up index. Something that links to this type of article and avoids all the discussion noise we are all guilty of creating.

  5. #5

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    Quote Originally Posted by mrriggs View Post
    Did you happen to measure the stem length of the secondary diaphragm? Does it match up to any of these? http://vb.foureyedpride.com/showthre...=1#post1818838
    He actually brought two E4 LIST-50151's, to put together one good one from the two or whatever. I chose to go with the dirtier one that still had some of it's original plating finish on it, that cleaned up okay, as opposed to the other that had been partially disassembled and sand blasted.



    Anyway, both old diaphragms and the new Napa kit diaphragm all approximate the -4's dimensions. I measured them all with a dial caliper and found 2.045" to the hole centers and 2.275" to the ends of the stems. Between examining two carburetors as is and the rebuilt one with the new diaphragm, it doesn't seem to be coincidence. I did notice that they don't over-travel much prior to installing onto the throttle shaft bracket stud, such as I have seen (more preload) with other Holleys, but there is enough preload with this 4180 that the secondaries are closed fine by the (purple) spring at idle. In your case, maybe an incorrect or incorrect stud location throttle shaft end bracket is the culprit... ? As you know, these have a thicker throttle base, which might change up where the stud needs to be. These are to be picked up in a couple hours, I'll have a look at the 4180 brackets and a another from a traditional carburetor and report back any differences...

    ... nope, no difference between the 4180 brackets and with multiple brackets I have here, and all main bodies (1850, 3 3310's, 6619-1, and the 4180's) on hand measure 1-1/2" from the upper diaphragm housing mounting screw taps and the base of the main bodies. The difference can only be stem length, possible vertical housing casting differences, and there's the 4180's base thickness difference, which makes no difference with these 4180's...
    Last edited by Walking-Tall; 09-28-2017 at 01:35 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/

  6. #6

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    Quote Originally Posted by erratic50 View Post
    Great write up - thank you!

    A person almost wants to make a tech write up index. Something that links to this type of article and avoids all the discussion noise we are all guilty of creating.
    Thank you, and you're quite welcome.

    True.
    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. #7

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    Quote Originally Posted by Walking-Tall View Post
    Anyway, both old diaphragms and the new Napa kit diaphragm all approximate the -4's dimensions. I measured them all with a dial caliper and found 2.045" to the hole centers and 2.275" to the ends of the stems. Between examining two carburetors as is and the rebuilt one with the new diaphragm, it doesn't seem to be coincidence. I did notice that they don't over-travel much prior to installing onto the throttle shaft bracket stud, such as I have seen (more preload) with other Holleys, but there is enough preload with this 4180 that the secondaries are closed fine by the (purple) spring at idle. In your case, maybe an incorrect or incorrect stud location throttle shaft end bracket is the culprit... ?
    Excellent, thank you. It's good to know the 135-4 IS the right diaphragm. Mine has all the right pieces so I'm thinking now that the -4 diaphragm I have (came on the 6619) was not properly installed and is not fully deploying. It worked on the thinner base plate because of the added preload but was off just enough to not work with the thicker 4180 base plate. I'll get a new 135-4 and give it another shot.

    Thanks again for clearing this up, once and for all.

  8. #8

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    Quote Originally Posted by mrriggs View Post
    Excellent, thank you. It's good to know the 135-4 IS the right diaphragm. Mine has all the right pieces so I'm thinking now that the -4 diaphragm I have (came on the 6619) was not properly installed and is not fully deploying. It worked on the thinner base plate because of the added preload but was off just enough to not work with the thicker 4180 base plate. I'll get a new 135-4 and give it another shot.

    Thanks again for clearing this up, once and for all.
    Let us know how you make out.
    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. #9

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    Here's the first instance I have encountered a different passenger side secondary throttle shaft bracket, which obviously calls for a shorter stem vacuum secondary diaphragm. The one on the left is what came off of a LIST-6947, D5TE-9510-EA (found on 1975+ 390 4-barrel Ford trucks)... different/shorter for intake manifold clearance issues or whatnot... and the one on the right is garden-variety common on most anything else (4180's, 1850's, 6619's, 3310's, etc.), all requiring a longer stem vacuum secondary diaphragm....

    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/

  10. #10

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    Pardon the repetition, but I believe the following is useful to be posted in numerous places...

    A shamefully ridiculous example of why I tell folks in regard to Holley carburetors, "if you want a good one, get an old one":


    Posted at racingfuelsystems forum, entitled "Brand New Blunder #??? - A Heads Up..."

    "So a local (repeat client) fellow contacted me asking if I could fine tune his brand new spread bore vacuum secondary... that with a few miles of driving his '77 Malibu he found that it would hesitate upon light part throttle "tip in"...

    Observation #1 was a throttle lever bent over toward the main body badly, so badly that it was bent all the way down to the throttle shaft area and loose on the throttle shaft, obviously dropped before it went into the box, and bumping into the driver's side secondary link lever at wide open throttle as well... and a secondary stop bracket not allowing full wide open of the secondary throttle plates... idle screw backed out, fully shut primary throttle plates, he said still idled way too fast, primary lever and idle screw tip not even inline with each other (primary throttle shaft not fully installed/seated laterally originally), and quite open secondary throttle blades...

    Observation #2 was small appearing primary idle air bleeds, and large idle mixture passages and blunt-tipped idle mixture screws... so I told him it is a "reverse-idle" unit, and it'll have passage holes into the primary bores, blah blah blah how "reverse-idle" works etc... I don't remember where now, but online somewhere that sells these states that the 80555-1 4175 650 spread bore vacuum secondary has a "forward" idle circuit... I presume as opposed to "reverse"?... hmmm, okay...

    Observation #3 was NO holes/passages into the primary bores for "reverse-idle"... so, in a nutshell, it has standard idle main body and base plate, and a "reverse-idle" primary metering block and mixture screws... at first I got him back here and showed him all of their "quality control" and "attention to detail", and thought completing "reverse-idle" would be the best course of action to make it behave... but after some more thought about it, I decided against that, because it would mean blocking the large standard idle discharge holes in the base plate, drilling new small ??? size constant idle feed holes below the primary transfer slots, and drilling ??? size passage holes into the main body... so instead I drilled the idle mixture screw passages in the PMB with a #29 drill, tapped 8-32 thread on through the passage, and installed 8-32x1/8" brass socket set screws with 1/16" holes in them, so that regular sharp tip idle mixture screws can be used...

    Observation #4 was air bleed sizes crazy in contrast to the handful of these (other, older, LIST-7002 etc.) that I have dealt with before, as well as somewhat larger than usual primary idle feed restrictions at 0.029"... and #64 primary jets where #62's are supposed to be according to documentation...

    Here are it's original calibration details as I found/measured:
    - 0.029" PIFR's (?) & 0.035" SIFR's (#54 SMP - specs not listed anywhere btw)
    - 0.053" PIAB's (?) & 0.051" SIAB's (?)
    - 0.036" PMAB's & 0.040" SMAB's (?!)
    - #64 PMJ's (?) & 0.081" secondary main circuit holes (#54 SMP - specs not listed anywhere btw)
    - 0.057" PVCR's
    - 0.040" pump shooter (?!) and orange pump cam in position 2

    So I remedied the metering block like explained above, loosened throttle blade screws and shuffled shafts and blades around so they were correct, got out the brass and drills and created 6-32x1/8" 0.026" PIFR's (very mild stock replacement camshaft in rebuilt 350) and installed those in the block, installed #62 PMJ's, drilled and tapped and installed 10-32x3/16" 0.070" PIAB's, 6-32x1/8" (the secondary constant idle feed holes seemed a bit big at about 0.030", so I chose to create) 0.040" SIAB's and 6-32x1/8" 0.026" SMAB's, and installed new regular idle mixture screws and the orange pump cam in position 1... not having any "anti-pullover" shooters of other/smaller sizes on hand, the rather large 0.040" remains in it...

    A couple hours after picking it up, he was back at the door, beaming and grinning, telling me to come check out my handy work. He brought the car, and it was idling in the driveway slowly and nice and smooth, and he said it's working night and day real nice, and making far more sense setting idle speed and mixture... and when he left here, it launched real good, barking out the exhaust, lifting the nose of the car some and was off down the street, lol!

    Thought I'd share this with you guys who may end up dealing with one of these further enhanced (translation: EFFED UP) versions of the "new and improved" that come brand spankin' new outta that place and cost this fellow 750 smackers... for what? Nearly complete re-calibration necessary so that it will just FUNCTION correctly... pardon my french, but the pompous jackasses who apparently know-it-all really should be knocked down a few notches somehow... I wish..."

    So yeah, the moral of the story... stop buying expensive new garbage from giant monopolizing corporations, because contrary to their marketing and such, they do not know WTF they are talking about or doing there at all anymore.
    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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