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Kill bleeds and check balls?

dla4567

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My outboard carbs have check balls in the diaphragms. The secondaries never open regardless of which diaphragm spring. I've looked at others and they don't have the check balls and work fine. When I remove the check balls the secondaries open waaaay to soon. I suspect that the carbs with the check balls have smaller kill bleeds to create a greater vacuum around the restrictive check balls. I've put some grooves on the seat to allow some more vacuum to the diaphragms with good results but I don't feel this is the best solution. Does anyone know the correct kill bleed size or if there are different sizes? My carbs are the correct ones for 1970 440, and the kill bleed size is .046". From what little I remember this seems small. Also wondering when this check ball thing started and if any originally came with check balls? When I mention the check balls to some of the guys that have been running six packs for years they look at me like I've got 2 heads.
 
those carbs never came with check balls; toss them.. the wrong size check ball can cause the carbs to stick open at wide open throttle; i know from experience. i've experimented with check balls and my conclusions were that they were somewhere between opening too late to the kiss of death. those carbs came with yellow springs from the factory. that's a good starting point. '69 carbs came with purple springs but had different bleed sizes. having the heat blocked in the intake can cause the carbs to open more violently. i always used some heat for smooth operation. i did a track test once on a set of '70 carbs. for every step heavier than the yellow springs the car went a tenth slower in the quarter. i did find that purples are a nice compromise.
 
I'd like to run them with out the check balls but when I remove them the secondaries open almost immediately and all the way even with the black spring. (Major bog). That's why I'm thinking the kill bleeds would need to be larger. Would like to know what size other carbs are before drilling them out. After it's done it's hard to put them back where they were. Also if others are the same size then maybe I need to be looking elsewhere.
 
i wonder if your bog is opening related. the black springs won't begin to open until above 4000rpm in a normal situation. i'm thinking you have a fuel flow problem. keep in mind that once you drill those kill bleeds there's no going back.
 
i wonder if your bog is opening related. the black springs won't begin to open until above 4000rpm in a normal situation. i'm thinking you have a fuel flow problem. keep in mind that once you drill those kill bleeds there's no going back.

Lew,you can go back,the kill bleeds are .043 for most applications rather than small block.Ones that I find that have been enlarged I tap the hole and use a 8x32 allen head set screw drilled to the correct size.
 
They are definitely opening, I can see them, and it's nowhere near 4000 rpm. They start to open as soon as you crack the throttle. I don't what to drill them out yet. But if I could get an idea of bleed sizes on other carbs that would answer some questions. I have had no luck with getting specs from Holley or any other sources. I bought the six pack book and that book is worthless. You would think that the bleed sizes would be written down somewhere or somebody would know but I've had no luck so far. (After the bog you better hold on)
 
I just told you .043 is what they should be,I have nine end carbs and all but one are .043,the other one is all screwed up!If your kill bleeds are .046,they have already been drilled.If you can find one of these it will answer all your questions.As for Holley,if you can even reach them you may not get a correct answer,their tech people come and go and most are not familiar with 40 + year old carbs.
 

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Thanks 62max, that's the kind of info I was hoping for. Sorry I missed your first post.
 
It might be a dumb question, but what is the vacuum source orifice like? Is that oversized, giving you too much signal? Just a thought.
 
this might help

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maybe better pic
 

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Everything is hooked up correctly, just like in the pictures. I called Phil Fish and got some good info from him. He said there were different bleed sizes depending on carb and the check balls should not be there. After discussing it with him he believes there may have been other modifications done. Rather than chasing my tail not knowing what has been done to these carbs, (and because it's cold), I'm just going to send them to him to take a look at. I enjoy working on this kind of stuff, but in this case I don't know what I don't know. And sometimes saving money is expensive. Thank for all the input, I'll let you know what he finds and how things turn out.
 
They should run off venturi vacum. Now on the 4 barrel vacum carbs the reason they use the check ball is because with the right size hole to make them open correct they wont bleed off fast enough and when you let off the gas they will stay open to long. So they use the check ball and make the hole the right size with the slots going by the check ball so they open at the right time and when you let off the gas the check ball lifts off its seats and makes the hole larger so they close right away. Thats how it should work but as you said I have heard of guys removing them and saying they work ok but I have never done it myself as I usually run just a Double pumper carb on my car. Ron
 
They should run off venturi vacum. Now on the 4 barrel vacum carbs the reason they use the check ball is because with the right size hole to make them open correct they wont bleed off fast enough and when you let off the gas they will stay open to long. So they use the check ball and make the hole the right size with the slots going by the check ball so they open at the right time and when you let off the gas the check ball lifts off its seats and makes the hole larger so they close right away. Thats how it should work but as you said I have heard of guys removing them and saying they work ok but I have never done it myself as I usually run just a Double pumper carb on my car. Ron
Ron,
I do on an average about 20 sixpack restorations a year,I have only seen one set in 30 + years with check balls in the secondary diaphragms and that was because someone put them there.I have a few N.O.S. end carbs and I can guarantee you if I take them apart there are no check balls.With the O.E.M. sixpack linkage the throttle plates are closed mechanically as soon as you lift off the throttle thus no need for a check ball.
 
62MAX- where in pa are you located? I'm about 30 miles north of Pittsburgh.
 
Ron,
I do on an average about 20 sixpack restorations a year,I have only seen one set in 30 + years with check balls in the secondary diaphragms and that was because someone put them there.I have a few N.O.S. end carbs and I can guarantee you if I take them apart there are no check balls.With the O.E.M. sixpack linkage the throttle plates are closed mechanically as soon as you lift off the throttle thus no need for a check ball.


Actually that is how Holley puts it for the four barrel carb so I thought they meant the same for the six pack setup. All of my work has been on four barrel vacum carbs as I just assumed they would do it the same on the 6pk since its vacum actuated and I was taught that about how they work many many years ago. If they dont use the check ball I wonder how they would overcome the fact that they need to bleed off the vacum fast enough so they dont hang open to long when off the gas. But it sounds like you have had way more 6pk end carbs apart then I have. I am glad you told me that as like I said I just assumed that meant the 6pk carbs should have the check ball. And all the info I can get on vacum carbs is always on the vacum secondaries on the four barrels. I really cant find the info thats specifaclly for the 6pk setup. Now you have me wanting to look into the 6pk setup deeper since I assumed most used the check ball like the four barrels. Thanks for the heads up. Ron
 
Ron,here is the breakdown on a 3659 Chevrolet 427 Tri Power end carbs and the Chrysler.The original pictures are direct from Holley but the part numbers are different because of a different parts vendor.The Mopar carbs are the same other than the base,the Chevrolet doesn't use mixture screws in the base on the end carbs because of the configuration of the main body.Picture 199.jpg
 

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Check this article out, some good info.

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Thanks for the in fo guys. Thats a nice 6pk article but they dont mention a check ball. All the Holley vac carbs have the kill bleed as the vac 4 barells have always used that setup even with the check ball as once the throttle blade opens on the vac side the kill blleds then helps hold it open as it gives it more venturi vacum once it opens. Holley says on the 4 barells the check ball is needed so it lifts off its seat and releases the vacum in the diaphram so the secondary does not hang open to long as they say if they dont make the feed hole larger (by the check ball lifting) it takes to long to beeld the vacum out and the secondaries dont close fast enough. They still dont say in here why they dont use the check ball setup since all the vacum carbs have the kill bleeds in them. Anyway thats for the great info guys. Ron
 
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