Kill bleeds and check balls?

I have had a few original six pack cars and never saw a check ball.. As far as closing the secondaries the linkage dose that when you let off the throttle. Not sure why yours has it but they made several variations of these carbs and yours may be one.

I would call Promax or Six pack solutions, these guys will know for sure.

lewtot184
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.

that is the first thing.

62MAX
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.

that is the second.

these guys know their stuff.

I cant see how on the four barrel the check ball should make the secondaries stick open as the reason for the check ball is for faster closing of them. I guess if the check ball was stuck and would not lift off the seat it could make them hang open longer. According to Holley on the four barrel the vacum hole to the secondaries is made to large so they would open to fast so they put the check ball in to make the venturi vacum source hole smaller so they open at the right speed but they would hang open if the hole stayed that small so the check ball lifts off its seat to make the vacum source hole larger and bleeds the vacum out of the diaphram faster so they close fast enough. So it makes me wonder what they did different when they dont use the check ball as even the ones with the check ball have the kill bleeds as they all have them as they help make the venturi signal stronger when the secondaries or end carbs open. It just makes you wonder why many four barrel's use the check ball but not the six pack's ? Many guys with the four barrel carbs used to remove the check ball and they would open alot faster which according to Holley is to fast for average driving. I guess they just found a happy medium to make them open and close good enough without the checkball. Ron

ron, the check ball is to regulate the opening. there are two balls, small and large. the small ball can stick in the vacuum passage preventing the vacuum pod from refilling with air causing WOT to stick open, been there done this. the kill bleed doesn't react quick enough for immediate throttle closing. the larger ball will not stick in the vacuum passage but will delay opening and closing, done this too. best bet is don't use them. there were some 4bbl vacuum pods that did have a groove in the well that a ball would be placed in. i'm sure this was specific to a carb designed to use a check ball. 6-paks don't have this and i've never seen a performance 4bbl carb with this.

Holley has only ever showed just one check ball in their pics that I have. And it is really only so it closes fast enough by unseating and letting the vacum bleed out faster with the larger hole. They may have changed where the kill bleed ties in to the primary venturi vacum to eliminate the check ball all together in the 6 pk as I can never find any info on that. I am just going from the info and pics in all of my Holley books as they always show a pic of a four barrel and all my pics all have the one check ball. And they never say why no check balls in the 6 pk or what they may have done different to eliminate the check ball on 6 pk's. I dont remember how much faster the secondaries open when the check ball is removed as I have not used a vacum carb in about 30 years as I like Double Pumpers. I guess the check ball did not make enough difference since some dont have them but I have also read where some carb guys say dont remove the check ball if it has it. Ron

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Here is the pic out of one of my Holley books. Ron



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And here is some info about it from the same book. Ron

ron, i think your misunderstanding the check ball. if you have a chance to play with this you'll have a better understanding. the check balls to retard the opening rate of the secondaries. they are a restriction.

lewtot184 said:

ron, i think your misunderstanding the check ball. if you have a chance to play with this you'll have a better understanding. the check balls to retard the opening rate of the secondaries. they are a restriction.

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The check ball is there because if they use the same size opening without the check ball they will open the same but they will stick open to long and not bleed the vacum out fast enough. The reason for the check ball is so it can lift off its seat and make the vacum port larger when you let off the gas so the secondaries will close right away and not hang open. Its not that they need to restrict the vacum port with the checkball to control the opening its because they need to make the vacum port larger when the throttle closes and so the vacum will bleed out of the vacum pod fast enough. If you read the paragraph I posted it even says that. If the size of the vacum port hole would bleed vacum fast enough when the throttle is closed then they would not need the check ball and the vacum port hole could be the needed size without a check ball. I do understand it and thats why I wonder what they did different when they dont use a check ball. Ron

383man said:

The check ball is there because if they use the same size opening without the check ball they will open the same but they will stick open to long and not bleed the vacum out fast enough. The reason for the check ball is so it can lift off its seat and make the vacum port larger when you let off the gas so the secondaries will close right away and not hang open. Its not that they need to restrict the vacum port with the checkball to control the opening its because they need to make the vacum port larger when the throttle closes and so the vacum will bleed out of the vacum pod fast enough. If you read the paragraph I posted it even says that. If the size of the vacum port hole would bleed vacum fast enough when the throttle is closed then they would not need the check ball and the vacum port hole could be the needed size without a check ball. I do understand it and thats why I wonder what they did different when they dont use a check ball. Ron

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believe what you want. it's obvious you have no real world experience with this and a 6-pak.

My understanding is the four barrel carb needs the check ball because it needs to bleed off the vacuum to close. The six pack does not because it has mechanical linkage to close secondaries. The four barrel also has notches on ball seat to allow air to pass the ball. The six pack does not because it never came with the check ball and if you add it (as in my case) it will block passage completely and not allow vacuum to diaphragm to open secondaries. I really appreciate all the input, things are becoming clearer and learning a lot.

dla4567 said:

My understanding is the four barrel carb needs the check ball because it needs to bleed off the vacuum to close. The six pack does not because it has mechanical linkage to close secondaries. The four barrel also has notches on ball seat to allow air to pass the ball. The six pack does not because it never came with the check ball and if you add it (as in my case) it will block passage completely and not allow vacuum to diaphragm to open secondaries. I really appreciate all the input, things are becoming clearer and learning a lot.

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Sounds like you finally got it.

lewtot184 said:

believe what you want. it's obvious you have no real world experience with this and a 6-pak.

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Most of the ones I worked with were vacum 4 barrel carbs which usually use the check ball which apparently you dont understand just how the check ball works and why its there. Its in plain writing that I posted that its only there to lift off its seat and release the vacum in the pod fast so the secondaries wont hang open to long. If no six packs dont use the check ball then I am not debating that I am only wondering what they did different to not use the check ball and no one seems to know what the real difference is. When you read Holleys book as to why they use the check ball in the 4 barrel carbs its simple to see they say the vacum secondaries will not close fast enough if they dont make the vacum port larger on decell to bleed the vacum pod faster. So why is the 6 pk different ? Maybe with two carbs and both kill bleeds instead of one like in the four barrel then maybe thats why the secondaries close fast enough on the 6 pk. The vacum four barrel has one kill bleed which you could also modify to change the opening and closing rate if you wanted to just like the 6 pks but since it has a check ball most feel thats what they want to mess with. Dont care how many you worked with as I know carbs as good as anyone on how they work and have done them for over 40 years but I admit I have never owned a 6 pk car nor has my friends but I know how every system works on all Holley carbs including the 6 pks but why did they stop with the check ball and not use them on the 6 pk ? If you know then lets here it as why you feel they dont use a check ball on the 6 pks ? Ron

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dla4567 said:

My understanding is the four barrel carb needs the check ball because it needs to bleed off the vacuum to close. The six pack does not because it has mechanical linkage to close secondaries. The four barrel also has notches on ball seat to allow air to pass the ball. The six pack does not because it never came with the check ball and if you add it (as in my case) it will block passage completely and not allow vacuum to diaphragm to open secondaries. I really appreciate all the input, things are becoming clearer and learning a lot.

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The four barrell's also have a mechanical link to close the secondaries when the primaries close all the way. Its the sloted link that mechanically pulls the secondaries closed when the primaries close all the way but if you lift the throttle to 1/3 to 1/2 then it dont close them all the way so they want the vacum to release fast enough and used the check ball. If you read the Holley book they make it sound like the secondaries will open way to fast if the check ball is removed as then it has a larger vacum port all the time not just when the check ball lifts off its seat. But I hear of some guys removing the check ball. Myself I have not removed it on the ones that have it. I also agree if its made with no check ball you cant add one as it has to have the calibrated slots in the seat to work with the check ball. Ron

Ron,your question from your post:
"but why did they stop with the check ball and not use them on the 6 pk" ?

your answer from the post above yours.
"The six pack does not because it has mechanical linkage to close secondaries."

Plain and simple,the mechanical linkage eliminates the check ball on 6 pk carbs.The sixpack end carb has no slotted linkage,as soon as you are off the throttle they close,front pulled shut,rear pushed shut.

62MAX said:

Ron,your question from your post:
"but why did they stop with the check ball and not use them on the 6 pk" ?

your answer from the post above yours.
"The six pack does not because it has mechanical linkage to close secondaries."

Plain and simple,the mechanical linkage eliminates the check ball on 6 pk carbs.The sixpack end carb has no slotted linkage,as soon as you are off the throttle they close,front pulled shut,rear pushed shut.

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I cant see that being right since the 4 barrel does have a mechanical back up and the 6 pk would have to have a slotted type of mechanical linkage where it lets the vacum open the carbs when you nail the gas as the vacum pulls its link through the slot and when open it hits the end of the slot and then closes with the throttle. It has to be that way or the mechanical tie in would be what was opening the end carbs and they would not need the vacum source so I cant see that being it. The 6 pk carbs can not be mechanically tied at a 1 to 1 ratio as they have to let the vacum still open it just like the 4 barrel does or they would be mechanical carbs. The 6 pk linkage has to work on the same princeable as the four barrel and let the vacum pods open the end carbs and the mechanical linkage will pull the end carbs shut the same as the four barrel. It has to work that way to be vacum opperated. It seems no one really knows and I cant blame anyone since I cant find the info from Holley themselfs.
My best bet is since the 6 pk has two vacum pods it then has two kill bleeds and the end carbs use the same venturi vacum source from the center carb. So I would feel with the vacum port and 2 kill bleeds it must bleed off vacum fast enough to work ok. And since the one vacum source has to open 2 carbs instead of one I guess the vacum port is a larger hole then on the four barrel which will also bleed off vacum fast enough to not need a check ball. Thats my best guess why no check ball on the 6 pk carbs. Holley feels the four barrel dont bleed off vacum fast enough so they use the check ball to open the vacum port hole larger to bleed the vacum off since its only one vacum pod and one kill bleed. Ron

Here is the sloted link on the 6 pk setup just like the four barrel uses. This is the center carb and you can see the sloted link on the main shaft as the end carbs both hook to a link that ties into this slotted link. Ron



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Here is the end carb as it has no acell pump. The link get a rod tied to the single hole in the throttle shaft which joins up with the other end carb and goes to the slotted link in the center carb. This link that hooks to the center carb slotted link lets the vacum open the carbs but assures the end carbs close when the center carb goes closed just like a four barrel works. I cant seem to find a good pic of the drivers side of the 6 pk setup as this is on the drivers side. Ron

Both sides

View attachment 300676

Thank you as thats one of the best pics I have seen of the drivers side 6 pk. You can just see the slotted link where the end carb rods go to. The linkage still hides alot of it. Ron