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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 02:02 PM.
    Mike
    1986 Mustang convertible ---> BUILD THREAD
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1966 Ford Fairlane sedan
    1966 Ford Fairlane GT
    1981 Mercury Marquis Brougham
    1980 Capri RS Turbo
    1971 Mustang
    1974 Pontiac LeMans

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

    The other one... 2005 Lincoln LS 3.9L V8

  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

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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 02:35 PM.
    Mike
    1986 Mustang convertible ---> BUILD THREAD
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1966 Ford Fairlane sedan
    1966 Ford Fairlane GT
    1981 Mercury Marquis Brougham
    1980 Capri RS Turbo
    1971 Mustang
    1974 Pontiac LeMans

  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
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1966 Ford Fairlane sedan
    1966 Ford Fairlane GT
    1981 Mercury Marquis Brougham
    1980 Capri RS Turbo
    1971 Mustang
    1974 Pontiac LeMans

  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
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1966 Ford Fairlane sedan
    1966 Ford Fairlane GT
    1981 Mercury Marquis Brougham
    1980 Capri RS Turbo
    1971 Mustang
    1974 Pontiac LeMans

  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
    1983 Mercury Cougar LS
    1986 Ford Thunderbird ELAN
    1966 Ford Fairlane sedan
    1966 Ford Fairlane GT
    1981 Mercury Marquis Brougham
    1980 Capri RS Turbo
    1971 Mustang
    1974 Pontiac LeMans

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