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Tech: A Dummy's guide to Learning and Rebuilding a Holley 94 6x2 setup

Discussion in 'The Hokey Ass Message Board' started by displaced_kiwi, Dec 26, 2007.

  1. displaced_kiwi
    Joined: Nov 20, 2005
    Posts: 247

    displaced_kiwi
    Member
    from Olathe KS

    Tech: A Dummys guide to Discovering and Rebuilding a Holley 94 6x2 setup




    For some this is Tech / How to, for some it will be a snooze! I am no carb expert, in fact carbs drive me crazy, but I am a firm believer in the more the merrier! I’d appreciate some feedback on this, as it’s a rebuild at home over thanksgiving weekend (and then some) by me with limited tools and enough knowledge to be dangerous! I generally think of myself as the dummy when it comes to knowledge on the hamb. So if I have not done something I should have or vice-versa fire away (I have my flame retardant undies on!) Each image is a link to a fullsize image.



    When my car was really coming together I looked at the carbs, decided they were ok (I was just to eager to be able to drive it) and then “fire in the hole”, whoa, wait no really, I had fire coming out of the center passenger side carb. Hmmm, so I did a quickie rebuild of the 2 center carbs and tried again. I could get it to run only if I kept pumping the pedal. It wouldn’t idle, had fuel leaks from the throttle shafts and other random places, backfired once loud enough to make my ears ring and vision go funky (at that stage I quickly shut the garage door and called it a night!). So I looked into them a bit more and realized that I cannot rush into driving the car and given that everything else is rebuilt or new, skimping on maybe the most complicated parts would not be wise.



    Here is what I started with - oddly enough it looks almost the same as what I finished with !


    [​IMG]




    So lets rebuild them. What I knew going into it – I have 6 matched Holley 94’s (2100’s) on a
    Weiand Dragstar manifold. I knew my accelerator pumps in the middle 2 are suspect (search my posts). It is a progressive setup, running the center 2 as primaries and the outside 4 as secondary (the outside 4 have a straight linkage). I don’t like the linkage for the middle carbs and will redo it - basically I don’t trust it not to stick open. I had fuel leaking out of 3 of the throttle shafts and they are all a little sloppy. I have one secondary carb that just pours fuel down its throat. I have one primary that doesn’t appear to do much at all now. I don’t know what is in the carbs (jet sizes, power valve sizes all unknown). I am not going to change anything that I don’t know enough about at this stage. I can do that once I get things running and learn some more…



    I will go through one primary and one secondary. In prep I had purchased six rebuild kits, six new .003 oversize throttle shafts, two 2x2 progress linkage kits (to modify my existing primary to secondary linkages) and a bunch of return springs.



    First I removed all the carbs and laid them out in order. For working on each carb, I divide them up into the 3 main parts – top, middle and bottom :)



    PRIMARY CARB



    Take the top and base apart so you have the three main components.



    For my carbs that is removing the connecting rod from the throttle shaft plate to the accelerator pump rod and undoing the screws on the top and the 3 screws for the base (2 on top and one underneath)


    [​IMG]


    The TOP:



    Teardown:


    First thing I notice after taking the top off this carb is that the fuel bowl was bone dry. The shut off needle is stuck and when I free it it tends to stick closed. Take the float off – it just has a needle holding it in place. Then unscrew the shut off valve.


    [​IMG]
    [​IMG]
    [​IMG]


    Assembly:


    While it is bare I run air down through it. I also give it a light sanding my “truing device” (a piece of sand paper taped to a flat table). Then I lay it ontop of the middle when the middle is completely apart and has also been lightly sanded. (When I am happy that the top and middle do not have to much air gap I put them back together.) I replaced the fuel shutoff with the one in the kit. The one I removed is a metal needle, whereas the one in the kit is a metal rod that pushes a rubber seal. Then I set the float level to 1.25 inches. Don’t let your brain fool you, the gauge in the kit has 32’s of an inch and the 4 on the gauge is actually 1.125 inches. I say this cause I did this on the first carb and had to take it apart again when I did the second one and had a “doh” realization.


    ** Notice my carbs do not have any chokes on them. They have been replaced with a bolt.


    [​IMG]


    The MIDDLE:



    Teardown:


    A bit more complicated than the top. First I removed the accelerator pump and rod. Then took the clip and spring off. For this accelerator pump I replaced the cup with the blue synthetic one in the kit. Next the underside. This is where the power valve screws in. Notice mine has a plug. Still remove it so we can clean things up and put a new washer under it. If you had power valves you would replace them. Power valves is something I am unsure of, I may need to put them in the Primary carbs – not sure yet. Then I removed the plugs on the outside of the fuel bowl area so I could get at and remove the main jets. My main jets are both 51’s. Check to make sure they are both the same size. Then you can remove the nozzle bar / accelerator discharge nozzle clamps. Remove each nozzle bar and unscrew the jet from each one. Then remove the discharge nozzle and there should be a needle valve in the tube under that nozzle (tip the section upside down and it should fall out). Oh one thing I did not mention or do is remove the ball bearing that lives at the bottom of the accelerator pump well. If you look down there you should see a retaining clip and a ball bearing underneath the clip. (I probably should have removed them?).


    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]


    Assembly:


    Alright at this stage I put all the parts to be cleaned in my basic but semi effective cleaning device (yep it’s a pot and a tin can with holes in the bottom), shake it about, leave it overnight – whatever floats your boat! Now I do the truing on the top and bottom of the middle section. After that is done I wash the middle section, blow air through all the holes and put it back together. Nothing really special here, just replace all gaskets/washers with new ones. I put some oil onto the plunger and the plunger arm when putting them back in. (see pictures below. I have showed both types of accelerator pumps - the longer and correct one with the synthetic cup and the shorter leather cupped one that comes in the generic rebuild kits. The leather cupped one gets soaked in oil and push out the edges with a screw driver when soaking so it fits more snugly (search my previous posts - thanks Bruce!) I run compressed air through all the jets before reinstalling them and through all holes in all the nozzles (basically if it’s a hole it gets air blown through it). I also used a babies bottle nipple cleaner (I had to qualify that one!) to clean down into the accelerator needle area and give it a visual with a light to make sure it doesn’t have anything stuck down there that could get under the needle. I also put the nozzle clamps into the vice and straighten them out (edited: Don’t do this! I found out when I put it all back together that one nozzle was loose and wasn’t squirting properly. You should leave the bend in them and the bend goes down towards the nozzle - so install them like a u and not a n!)


    [​IMG]
    [​IMG]
    [​IMG]
    [​IMG]


    The BASE:


    Teardown:


    I am replacing the throttle shafts, but I didn’t give much thought to the throttle plates. They seem to shut and seal ok visually, but they may get replaced. Anyway remove the idle screws and springs. Then remove the screws from the throttle plates – they are bent over on one side and you would not expect to reuse these. Then push out the throttle plates and slide out the throttle shaft. Remove the plate on the end of the throttle shaft that connects the shaft to the accelerator arm (that then attaches the accelerator pump). Make sure you keep the washer that is underneath this plate. Now I ran the base unit over my truing device until I was happy with the fit of it to the middle section and also happy that the base was nice and straight for a good seal the inlet manifold.


    [​IMG]
     
  2. displaced_kiwi
    Joined: Nov 20, 2005
    Posts: 247

    displaced_kiwi
    Member
    from Olathe KS

    Assembly:


    I wire brushed, painted, cleaned, blew air through it and rebuilt the base. I used a dab of grease to install the shaft so as not to score it. Then put the throttle plates back on, screw in the holding screws and (flare out the end of the screws so they wont fall out. I am sure there is a tool just for this but I tapped them with an appropriate punch. Be very careful, as you do not want to bend or damage the throttle shafts. Put the plate back that connects to the accelerator pump arm back on with the washer behind it. Put the idle screws back in. I unscrewed them ½ a turn and marked them.


    [​IMG]
    [​IMG]


    When you bolt the base back to the middle section make sure you choose the correct gasket. There were 2 in my kit and they are kinda similar, but one blocks the holes and has larger throat holes in it. Then connect the throttle arm to the accelerator pump rod.


    The throttle shafts that I purchased were the “extended” ones. Seeing as I did not need that I put my linkage arm back on the shaft, marked it and then cut it to length. Be carefull when you put your linkages back onto the shafts as the shafts are slightly larger (for me anyway and most likely for you if you are replacing them) you need to open up your old linkage arms. I only say this cause I cracked one of my linkage arms by trying to slide (er force) it on – and let me tell you that really F’ing annoyed me!


    [​IMG]
    [​IMG]
    [​IMG]




    SECONDARY CARB


    The TOP:


    Disassembly and reassembly is almost the same as for a primary as I have no chokes on either. But there are several key difference with the secondary carbs though - mainly the idle circuits are blocked off - also when you reassemble and get ready to run - make sure the idle screws are turned in all the way - ie off!



    The MIDDLE:


    The only difference for my setup here is that the spray nozzle idle outlets are blocked off with a solid gasket.


    [​IMG]
    [​IMG]


    The BASE:


    I have a piece of brass pipe blocking the (idle?) passageway between the two barrels.


    [​IMG]


    Disassembly and reassembly is the same as for a primary except that the idle mixture screws get screwed all the way in (so no fuel gets past the needle).


    Now its all back together – modifying my linkage




    So its all back together. I put the linkage for the secondary carbs back on. You need to make sure that the secondary carbs are fully closed. I do this (for each side) by adjusting the linkage so it fits into the carb arms with the arms in the closed position, attach the linkage, then I loosen one of the arms and press down on the butterflies on both carbs with a screw driver to make sure they are shut, then I tighten up the linkage.


    For my primary to secondary linkage, I am replacing what was on there. I hummed and hah’d about what to do and in the end bought 2 2x2 progressive linkage kits and used the arms from those. I installed them the opposite way around to how my original primary linkages were setup so it keeps things tighter/neater and I have plenty of clearance on the passenger side between the rear carbs linkages and the distributor. I have the adjustable collars on it so I can change the behaviour of the setup (ie make it all happen at once or as I have it set now – be progressive). Running it progressive - you do this by using a hole further away from the throttle shaft on the primary, mounting to a hole that is closer to the throttle shaft on the secondary (so the secondary has a smaller arc thus opens at a faster rate and catches up). I adjusted mine by mounting the linkages, loosening the collars on the primary to secondary shaft, opening all carbs wide open and tightening the collar that the primary pulls at that point. So I know when the center is wide open all are wide open. For me this means my secondaries come on at a third throttle. Then I close all carbs and tighten the collar that returns the secondaries. I also have a spring between the collar the secondary linkage which acts as a return spring (its light weight, so its really just assisting – but I think it’s a good idea).


    I then made a small bracket to go on the front carb mounting stud which I use to attach the return springs for the secondary and primary carbs. I extended down the rear linkage arm and run the spring along the bottom of the carbs to the front carb. Same for the primary, but it also gets a spring on top which goes back to a tab I put on the rear carb.


    [​IMG]
    [​IMG]


    OK, its been a couple of weeks since I did most of the work and I am still getting it tuned up. I am pretty close now. The rebuilds seem to have cured the leaks and I have run the motor for about 10 mins. I have done a lot of adjusting, starting, adjusting, starting etc. Right now I need to screw in the idle screws (make it leaner) but this is where I am at specs / tuning wise.

    * I am currently ¾ of a turn out on the idle mixture screws

    * the throttle position screws are unwound completely – so butterflys are all shut

    * 2lbs of fuel pressure on my regulator (not sure if that is 2lbs really, but that is what the dial is set to. If I make the fuel pressure any higher the center driver side carb keeps spitting fuel down its throat after shutoff).

    * All the main jets are 51

    * spray bar nozzles have 71 stamped on them.
    I haven’t driven it yet, but my aim is to at least drive it out and back into the garage this year (that’s within a week now). I have spent a lot of time messing around and me being me, I do it all myself and it takes me 10 times longer than it should. I had a lot of issues with timing/distributors which really messed me up and in general its been frustrating all the way along. Even doing the return springs took a week, of whatever spare time I had, to get them to close reliably and not be too stiff on the pedal. But I love the setup and cant wait for the driving part of the experience!



    Finally there is a lot of info already on the HAMB. Here are just a few links to try mainly for multi carb and holley 94 setups



    http://www.jalopyjournal.com/forum/showthread.php?t=77680

    http://www.jalopyjournal.com/forum/showthread.php?t=183529

    http://www.jalopyjournal.com/forum/showthread.php?t=176761&showall=1

    http://www.jalopyjournal.com/forum/showthread.php?t=39495&highlight=plugged+94+power+valves

    http://www.jalopyjournal.com/forum/showthread.php?t=54768&highlight=holley+94+power+valve

    http://www.jalopyjournal.com/forum/s...ead.php?t=4618

    http://www.jalopyjournal.com/forum/s...ght=multi+carb

    http://www.jalopyjournal.com/forum/s...ght=multi+carb

    http://www.jalopyjournal.com/forum/s...ght=multi+carb

    http://www.jalopyjournal.com/forum/s...ght=multi+carb

    http://www.jalopyjournal.com/forum/s...ght=multi+carb

    http://www.jalopyjournal.com/forum/showthread.php?t=210525&highlight=holley+94+accelerator+pump


    Good luck and like I say, I am not a Carb guy and these are the first 94’s I have played with so any feedback is welcomed.


    Cheers


    ricki
     
  3. chaddilac
    Joined: Mar 21, 2006
    Posts: 13,862

    chaddilac
    Member

    wow! That is cool!
     
  4. Royalshifter
    Joined: May 29, 2005
    Posts: 15,641

    Royalshifter
    Moderator
    from California

    Damn Sir that is the tech of the season. Thank you very much.
     

  5. touchdowntodd
    Joined: Jan 15, 2005
    Posts: 4,063

    touchdowntodd
    Member

    VERY VERY informative....

    now i wish i had kept my 6x2! hahahha, or atleast wish i had a motor that could hold it!
     
  6. superbell
    Joined: Mar 3, 2001
    Posts: 349

    superbell
    Member

    Great job, now I need somebody to do a tech on a 4 carb 94 setup!
     
  7. 55olds88
    Joined: Jul 23, 2001
    Posts: 2,384

    55olds88
    Member

    great post, when I get 4 similar victims for my 4x2 for the Olds I intend attacking using your methods.
     
  8. displaced_kiwi
    Joined: Nov 20, 2005
    Posts: 247

    displaced_kiwi
    Member
    from Olathe KS

    Thanks guys. I wanted to give something back to the hamb before the year is out. I started the article for the last tech week, but just didnt get it done in time.

    At this stage I have rebuilt, improved on and WILL make reliable a setup that has been together a long time, run hard and put away wet! When I bought it, it looked pretty good and I thought I could just slap it on and run it - oh how wrong I was! By documenting the process, especially the future tuning and setup - regardless of success or failure - it should be usefull info.

    cheers
    ricki
     
  9. Noland
    Joined: Oct 16, 2007
    Posts: 1,237

    Noland
    Member

    awesome,awesome info thanks for it
     
    47bob likes this.
  10. BAD ROD
    Joined: Dec 16, 2004
    Posts: 1,535

    BAD ROD
    Member

    Brillant! Very, very helpful. Thanks for putting the information together.

    I am looking to run 6 94's on my FE 390. I am still looking for a 6x2 FE manifold! Your information will come in very handy.

    Mike
     
  11. This is very timely, I am in need of rebuilding my 6x2 94 setup, you da man!

    I haven't read all this yet, but where'd you get those stacks?
     
  12. scootermcrad
    Joined: Sep 20, 2005
    Posts: 12,368

    scootermcrad
    ALLIANCE MEMBER

    OH YES!!!!! That is FANTASTIC!!!! Now that was some great tech posting! Well done and like Richard said... great timing!

    Who needs magazines when you have the HAMB!
     
  13. Terry O
    Joined: Oct 12, 2004
    Posts: 1,060

    Terry O
    Member

    Nice photos. Thanks for posting.

    Terry
     
  14. Bumpstick
    Joined: Sep 10, 2002
    Posts: 1,372

    Bumpstick
    Member

    THANK YOU!!!!! I've been hoping for something like this for so long. Thanks again. -stick

    Here's my collection.:D Awaiting rebuilds.

    [​IMG]
     
  15. displaced_kiwi
    Joined: Nov 20, 2005
    Posts: 247

    displaced_kiwi
    Member
    from Olathe KS

    They came with the carbs. They dont have any markings on them so I think they were custom made by someone. I do really like them! I plan to incorporate some kind of air filter inside them without any external modifications.

    Thanks scooter. Your right about mags. I subscribe to a few magazines and get more enjoyment and knowledge from the hamb. I've also noticed a lot of hamb references in various hot rod mags in past few months and a lot of the cars featured I saw here first!

    No probs and Nice collection! ... does that carb on the end of the first pic mean you'd take $20 for all carbs and parts on the shelf :D:D:D I have no spare 94's but I do have a small collection of 1920's from my /6.
     
  16. Nekronomicon
    Joined: May 23, 2005
    Posts: 814

    Nekronomicon
    Member

    Awesome! Thanks for posting this, best post in a looooong long time!
     
  17. MIKE47
    Joined: Aug 19, 2005
    Posts: 987

    MIKE47
    Member
    from new jersey

    Ricki, Thanks for this post. As you can see your timing is awesome. And I have another dozen in the basement!!

    [​IMG]
     
  18. collector
    Joined: May 18, 2006
    Posts: 77

    collector
    Member
    from madera,ca

    thanks for the tech. nice photos.w/good info. awesome!
     
  19. v8coupe
    Joined: Dec 8, 2015
    Posts: 15

    v8coupe

    @displaced_kiwi an old but great thread, and very interesting for me as ive just bought a 6x2 setup that needs a thorough going through. A real shame the pics have dissappeared, dont suppose you have access to them still? Pics help so much when reading tech stuff.
     
    kidcampbell71 likes this.
  20. Wow, I wish Photsuckit hadn't got greedy and ruined all the old threads.
     
    kidcampbell71 likes this.

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