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Six Pack outboard vacuum #2679517
07/20/19 07:06 PM
07/20/19 07:06 PM
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upstate western ny
sogtx Offline OP
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I cant leave well enuff alone so I put a fun gage
On my outboards to see what color opens where
plotting vs rpm .
Any one ever observe vacuum signal and
opening rate , or you too busy holding on ?


drive

Re: Six Pack outboard vacuum [Re: sogtx] #2679519
07/20/19 07:16 PM
07/20/19 07:16 PM
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So. Burlington, Vt.
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fast68plymouth Offline
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The 6bbls I’ve run on the dyno always used the pretty soft springs, and the secondaries would pop open surprisingly early when opening the throttle while bringing the motor up against the load.

Never bothered to take a reading off the secondary vacuum lines though.


68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads
Re: Six Pack outboard vacuum [Re: sogtx] #2679536
07/20/19 07:41 PM
07/20/19 07:41 PM
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Portland, Oregon
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Digger73 Offline
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Isn't the vacuum line from the center carb to the out board carb vacuum pods, just to give a small kick to start the opening?

Digger73 (Mike)


I live with fear everyday but, sometimes she lets me race!
Re: Six Pack outboard vacuum [Re: fast68plymouth] #2679568
07/20/19 09:08 PM
07/20/19 09:08 PM
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upstate western ny
sogtx Offline OP
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Originally Posted by fast68plymouth
The 6bbls I’ve run on the dyno always used the pretty soft springs, and the secondaries would pop open surprisingly early when opening the throttle while bringing the motor up against the load.

Never bothered to take a reading off the secondary vacuum lines though.


Neither can I nor can i find data ..
either way at 2.5 they start to tip in
And then once when i was really into it , theres was no reading , but boy they opened.
Wish i was a Holley engineer , lol .
After 20 + years of six paks, im gettin there ...

Just playin with springs and makin notes ..
i got this feeling when I put stickier tires on , Ill be doin it ALL over .

Re: Six Pack outboard vacuum [Re: sogtx] #2679599
07/20/19 10:52 PM
07/20/19 10:52 PM
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Bend,OR USA
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Cab_Burge Offline
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I put a small bolt or screw with a nut to lock it down in the return slot about half way full open on the center carb to start them opening when I hit throttle to WOT up scope wrench
Me like this lot, devil this is a old NHRA stocker trick up


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: Six Pack outboard vacuum [Re: sogtx] #2679684
07/21/19 10:31 AM
07/21/19 10:31 AM
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Brookeville, Md
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I ran purples on my old 440-6. 588 solid roller cam, 3800 stall. zero hesitation.


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Coming soon!!!!
Re: Six Pack outboard vacuum [Re: Digger73] #2679750
07/21/19 01:45 PM
07/21/19 01:45 PM
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Balt. Md
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383man Offline
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Originally Posted by Digger73
Isn't the vacuum line from the center carb to the out board carb vacuum pods, just to give a small kick to start the opening?

Digger73 (Mike)



That sends venturi vacuum to the vacuum pods. Then both end carbs have what they call a bleed hole which helps pull stronger venturi vacuum from the end carbs after they start to open to stenthen the venturi vacuum signal even more. Some people plug the bleed holes in the end carbs so the ends carbs will start to open sooner but it wont get the extra vacuum once they start to open. The bleeds in the end carbs are basically like a vacuum bleed off until the end carbs start to open and then they help to pull stronger vacuum as the signal will then be from all three carbs. Ron

Last edited by 383man; 07/21/19 01:46 PM.
Re: Six Pack outboard vacuum [Re: 383man] #2771988
05/07/20 06:33 AM
05/07/20 06:33 AM
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upstate western ny
sogtx Offline OP
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I guess I have a pesky old set
I guess that come with 50+ year old carbs .
Outboards open up great in 2nd-4th gear
under load .
Lighter springs didnt change quickness to open .
Just cant seem to get them to open up on a
1st gear burnout..
Maybe not enough load . ?
But the first to 2nd gear shift opens them.
I dont need to roast the tires off the rims , but
surprised I cannot in first gear.
Dont get me wrong . Its hazes tires for 100’
But not John Force style .

As far as cruising and normal accelerating
It is just about as fast as my Hellcat . (Not joking )
Wondering what im missing in the final tune ..

Go pro camera made me prove im running on center at most times .
Thats the coolest thing ive ever watched and streamed
to my smart tv...

Last edited by sogtx; 05/07/20 06:35 AM.
Re: Six Pack outboard vacuum [Re: sogtx] #2771998
05/07/20 07:49 AM
05/07/20 07:49 AM
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usa
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lewtot184 Offline
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Originally Posted by sogtx
I guess I have a pesky old set
I guess that come with 50+ year old carbs .
Outboards open up great in 2nd-4th gear
under load .
Lighter springs didnt change quickness to open .
Just cant seem to get them to open up on a
1st gear burnout..
Maybe not enough load . ?
But the first to 2nd gear shift opens them.
I dont need to roast the tires off the rims , but
surprised I cannot in first gear.
Dont get me wrong . Its hazes tires for 100’
But not John Force style .

As far as cruising and normal accelerating
It is just about as fast as my Hellcat . (Not joking )
Wondering what im missing in the final tune ..

Go pro camera made me prove im running on center at most times .
Thats the coolest thing ive ever watched and streamed
to my smart tv...
if you have '69 carbs then they will open slower than the '70-'71's. pretty sure '69's have a larger kill bleed and a smaller orifice in the center carb that the vacuum hose hooks too. carb list #"s with a -1 after them was supposed to take care of that issue.

Re: Six Pack outboard vacuum [Re: lewtot184] #2772017
05/07/20 09:19 AM
05/07/20 09:19 AM
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Benton, IL.
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DaveRS23 Offline
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I got my very first 6bbl because of the very issues being discussed here. A guy had bought a 4 year old 70 440-6 Cuda. Nice car, but was just old enough that the secondaries were inconsistent on their openings. Sometimes yes, sometimes no. None of us knew much of anything about that stuff back then. He messed with it, had others mess with it and soon enough, it was all messed up.

He became so frustrated with it that he offered to trade for the 340-4 in my 70 Cuda. My 340 was nothing special, only had a set of hedders, but it did run good. I really liked his set-up although I didn't know much about it. So we swapped everything in our cars, from the radiators to the trannies.

After a bunch of reading and experimenting, I did get the carbs to be more consistent. Added, cam, hedders, etc. Man, that thing was a monster. Street raced it for years. I even spun rod bearings and drove it home knocking. Pulled the pan and offending rod cap, polished the bearing off the crank and put it back together....in the car. Did that 2 or 3 different times.

But, like others have touched on, it had to have some traction (load on the engine) to get the secondaries to open.


KOS
Re: Six Pack outboard vacuum [Re: lewtot184] #2772103
05/07/20 01:29 PM
05/07/20 01:29 PM
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Prospect, PA
BSB67 Offline
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Originally Posted by lewtot184


if you have '69 carbs then they will open slower than the '70-'71's. pretty sure '69's have a larger kill bleed and a smaller orifice in the center carb that the vacuum hose hooks too. carb list #"s with a -1 after them was supposed to take care of that issue.



This. And any vacuum leaks anywhere in the "system" that actuate the carbs will affect their opening too.

Re: Six Pack outboard vacuum [Re: BSB67] #2772253
05/07/20 09:16 PM
05/07/20 09:16 PM
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upstate western ny
sogtx Offline OP
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All vacuum tite
Unless its internal in 50 yo carbs ...
i guess i wanted to be cool and run numbers carbs
when i have fresh ones on the shelf

I like abusing myself i guess , lol
Thanks for the toughts .

Its still scary fast, but just not john force fast on the
line..

Re: Six Pack outboard vacuum [Re: sogtx] #2772258
05/07/20 09:36 PM
05/07/20 09:36 PM
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Prospect, PA
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Originally Posted by sogtx
All vacuum tite
Unless its internal in 50 yo carbs ...



Did you check for vacuum leaks. If so, how did you do it?

Re: Six Pack outboard vacuum [Re: BSB67] #2772336
05/08/20 05:48 AM
05/08/20 05:48 AM
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upstate western ny
sogtx Offline OP
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Fair question .

Ive used propane listening for a rise in idle , and even watched
the tach from timing lite .
Ive yet to do that with a hot hot engine .

Ive Sprayed bottle water to see if it was drawing in.

Other than that , are there better methods . ?

I paid a lot of attention to the outboard pod
Connection to bodies .

Just because , ive done the suck test on the outboards tee hose.
They do open in unison with kill bleeds plugged or not .
This is irrelevant kind of , because i know they open.

I think ive been thorough or im missing a better
More accurate method .


Re: Six Pack outboard vacuum [Re: sogtx] #2772358
05/08/20 07:59 AM
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lewtot184 Offline
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Originally Posted by sogtx
All vacuum tite
Unless its internal in 50 yo carbs ...
i guess i wanted to be cool and run numbers carbs
when i have fresh ones on the shelf

I like abusing myself i guess , lol
Thanks for the toughts .

Its still scary fast, but just not john force fast on the
line..

there's nothing wrong with '69 carbs for performance. just understanding there is a difference may answer some questions. the '69's with the slower opening also used a purple spring which is one step heavier than the '70-'71 yellow spring. just swapping to the yellow spring will cover at least half the difference and the truth is the difference between the two is no "make it or break it" deal.

Re: Six Pack outboard vacuum [Re: lewtot184] #2772361
05/08/20 08:19 AM
05/08/20 08:19 AM
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Phila Pa
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So Andy... The problem is that they won't open in first gear some of the time? But the always open in second gear?

You haven't over tightened the baseplates? When you manually open the center carb after the engine is hot (engine off) do the secondary's "crack open" or are they completely free and smooth?

Last edited by scatpacktom; 05/08/20 08:25 AM.
Re: Six Pack outboard vacuum [Re: sogtx] #2772389
05/08/20 10:21 AM
05/08/20 10:21 AM
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Originally Posted by sogtx
Fair question .

Ive used propane listening for a rise in idle , and even watched
the tach from timing lite .
Ive yet to do that with a hot hot engine .

Ive Sprayed bottle water to see if it was drawing in.

Other than that , are there better methods . ?

I paid a lot of attention to the outboard pod
Connection to bodies .

Just because , ive done the suck test on the outboards tee hose.
They do open in unison with kill bleeds plugged or not .
This is irrelevant kind of , because i know they open.

I think ive been thorough or im missing a better
More accurate method .



Those things you did/checked have no bearing on the outboard carbs opening. A leak in any part of the outboard carb vacuum system would go completely undetected with what you did.

Do you have the 69 carbs as Lew asked?

Not only do they have the larger kill-bleed like Lew mentioned, the outboard throttle plates can stick in the throttle bores as mentioned, particularly in the 69 carbs. Also as mentioned, over torquing the base plate can cause binding. You can simply check these by hand with the engine off.

Re: Six Pack outboard vacuum [Re: BSB67] #2772395
05/08/20 10:34 AM
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lewtot184 Offline
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Originally Posted by BSB67
Originally Posted by sogtx
Fair question .

Ive used propane listening for a rise in idle , and even watched
the tach from timing lite .
Ive yet to do that with a hot hot engine .

Ive Sprayed bottle water to see if it was drawing in.

Other than that , are there better methods . ?

I paid a lot of attention to the outboard pod
Connection to bodies .

Just because , ive done the suck test on the outboards tee hose.
They do open in unison with kill bleeds plugged or not .
This is irrelevant kind of , because i know they open.

I think ive been thorough or im missing a better
More accurate method .



Those things you did/checked have no bearing on the outboard carbs opening. A leak in any part of the outboard carb vacuum system would go completely undetected with what you did.

Do you have the 69 carbs as Lew asked?

Not only do they have the larger kill-bleed like Lew mentioned, the outboard throttle plates can stick in the throttle bores as mentioned, particularly in the 69 carbs. Also as mentioned, over torquing the base plate can cause binding. You can simply check these by hand with the engine off.
I've always done the 600 grit paper thing to the end carb throttle blades no matter what year they are. in fact I think the new carbs are worse than the old carbs for binding.

Re: Six Pack outboard vacuum [Re: BSB67] #2772453
05/08/20 01:17 PM
05/08/20 01:17 PM
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sogtx Offline OP
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Originally Posted by BSB67
Originally Posted by sogtx
Fair question .

Ive used propane listening for a rise in idle , and even watched
the tach from timing lite .
Ive yet to do that with a hot hot engine .

Ive Sprayed bottle water to see if it was drawing in.

Other than that , are there better methods . ?

I paid a lot of attention to the outboard pod
Connection to bodies .

Just because , ive done the suck test on the outboards tee hose.
They do open in unison with kill bleeds plugged or not .
This is irrelevant kind of , because i know they open.

I think ive been thorough or im missing a better
More accurate method .



Those things you did/checked have no bearing on the outboard carbs opening. A leak in any part of the outboard carb vacuum system would go completely undetected with what you did.

Do you have the 69 carbs as Lew asked?

Not only do they have the larger kill-bleed like Lew mentioned, the outboard throttle plates can stick in the throttle bores as mentioned, particularly in the 69 carbs. Also as mentioned, over torquing the base plate can cause binding. You can simply check these by hand with the engine off.



Yes they are 69 1/2 carbs
Hoses
Nipples
Connections to main body
Seal between carb and pod have been gone through
Note, and this particular set of carbs have been
Gone through by maxwgn


Please elaborate on a more specific independent
vacuum test on the outboard components and your suggestion .

I was assuming you thought a poor base seal or
Other would/might cause this issue .. thus the propane test .

If there is a method , lmk .

Re: Six Pack outboard vacuum [Re: scatpacktom] #2772503
05/08/20 03:10 PM
05/08/20 03:10 PM
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upstate western ny
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Originally Posted by scatpacktom
So Andy... The problem is that they won't open in first gear some of the time? But the always open in second gear?

You haven't over tightened the baseplates? When you manually open the center carb after the engine is hot (engine off) do the secondary's "crack open" or are they completely free and smooth?


HI Tom , How are you ?
Yes weird deal , I suppose .
This ONLY happens in 1st gear at a start.

Baseplates dont seem to be warped on a flat table , I usually use a hand nut driver to titen the carb bolts .

I manually drew open the carbs so I can observe my outdboards opening and snapping shut .

I just confirmed , both outboards crack open a " c" hair when i open up the center . Engine is cold .

I readjusted my rods lengthened / shortened to double check their placement , still same result outboard crack open.

with engine running ,they DO NOT open .

Heres the weird thing that leads to Possibly a vacuum leak somewhere .

I have a gage hooked to outboard tees . cruising and tipping in slightly on acceleration on any gear other than 1st , I read 2.5-5"" of vacuum and
you can feel the the outboards opening .

I might need to learn how to vacuum test the carb itself.

The first gear issue happens with Polyglas OR wide fat sticky tires . So The engines definitely under load on a burnout.

Im not sure if this is because of a short 1st gear ( passon OD )
Im chipped at 6500 , maybe i should go 7 ..

ill test the secondarys after a run around the block and see results .

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