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70 super bee 440, 6 pack, High idle problem

I still and have always had "idle creep" where I set the idle around 925-950 RPM, but it runs around 1,050-1,100
The 440+6bbl has a Purple Stripe cam that I and others suspect is the .509/292° cam, and I LOVE the way it sounds, pulls strong to 6k (6,200 actually) although I try to keep it at 6k given the other specs, on paper it should roll off before 6k, it's hard because it pulls so hard.
Anyway, I believe the culprit is the outboard carb rods that control the opening of the throttle plates.
I am going to play with the # of turns and see if I can lengthen them 1 more turn. If they had a pressure spring integrated into them that would assure they press gently on the throttle plate arm to assure they close to the point that they are adjusted to, BUT absolutely allow the plates to FULLY open on vacuum, that would be ideal.
 
To be clear, the rods connecting the center carb's throttle lever to the outboards are not there to “control the opening” of the outboards, they are there to insure the closing of the outboards with center carb throttle closing. Disconnect them from the outboard levers, set your curb idle (if running a solenoid, disconnect the lead), re-connect and adjust the rods to side into the levers with no tension either way, start with the front carb rod.
 
72RoadrunnerGTX said:
To be clear, the rods connecting the center carb's throttle lever to the outboards are not there to “control the opening” of the outboards, they are there to insure the closing of the outboards with center carb throttle closing. Disconnect them from the outboard levers, set your curb idle (if running a solenoid, disconnect the lead), re-connect and adjust the rods to side into the levers with no tension either way, start with the front carb rod.
Click to expand...
Well, the rods do control the point at which the outboard carbs can open via the curved slot on the center carb.
Vacuum and vacuum pod spring pressure controls the rate of opening, and the rods along with reduced vacuum cause them to close.
Thanks for the rod/idle adjustment tips!
I'll try that sequence.
 
The point is, the rods are there to ensure that a mechanical force, the center carb’s throttle return spring, overrides all vacuum related opening signals/forces, to close the outboard quickly when the center carb closes. As designed, under normal use, the mechanism plays no role in the timing of when the secondarys/outboards open. No different than the similar mechanism on every vacuum secondary Holley 4 barrel.
 
biomedtechguy said:
I am going to play with the # of turns and see if I can lengthen them 1 more turn. If they had a pressure spring integrated into them that would assure they press gently on the throttle plate arm to assure they close to the point that they are adjusted to, BUT absolutely allow the plates to FULLY open on vacuum, that would be ideal.
Click to expand...

There should be no need for any mechanical force the keep the outboards closed while idling. Like all carbs, the throttle plates are off-center slightly on the shafts so that manifold vacuum at idle will apply a closing force. It takes quite a bit of force to crack open an outboard while idling, rods disconnected. Need to make sure the rods are not preventing the outboards from closing completely or you will have an inconsistent idle.
 
The rod that pulls the choke is designed to be bent to pull the choke open after warm up. The choke obviously should be vertical after warm up.
 
No.
Passenger side. The choke linkage has a heat activated pull off. The linkage is crooked and allows to make minor adjustments for cold and hot temps. Cycle the choke manually and you will see the linkage
 
Also as you can tell from the reply's there are a number of places that can cause this problem. Make no mistake the six pack idles on all three carburetors. If you have the fast idle solenoid make I would disable it first. As previously stated make sure the linkeage for the outboard carburetors are adjusted so that they are fully closed at idle. Ensure that the throttle linkage is correct for a six pack (four barrell hardware cable etc will not work properly). Make sure the vacuum lines on the passenger side are correct. CAUTION!! Incorrect placement of the vacuum lines can pull the out board carbs full open. Any doubt get a picture (I can send you one) before monkeying with these. If this is all correct I would check for vacuum leaks. There is an article on this site posted recently that tells how to on six packs. Read and adhere. Good Luck
 
72RoadrunnerGTX said:
Need to make sure the rods are not preventing the outboards from closing completely or you will have an inconsistent idle.
Click to expand...
That's the problem. It has been difficult to find the # of turns that allow the outboard carbs to fully close AND allow for a smooth motion at those pivot points, but I am absolutely going to try lengthening them and see if that resolves the problem. My 292/.509 cam w/open cutouts sounds really sweet at 850 vs 1k. That would also assure that the proper circuit of the metering block is in effect, although I think the Promax is designed for higher idle speeds.
:thumbsup: :lowdown: Thanks for the advice. I went from the 3x2 setup being a headache to not wanting anything BUT a 3x2 system.
The most important epiphany I had regarding the 3x2 system was learning how to set the outboard idle mixture screws by measuring RPMs effected by putting my finger on the bleed hole.
 
Last edited:
Be patient and persistent. The six pack is a great set up when "set up" correctly and tuned correctly. Exhilarating ride!
 
lyndondb said:
The rod that pulls the choke is designed to be bent to pull the choke open after warm up. The choke obviously should be vertical after warm up.
Click to expand...
That is something else I will do. I have had about an eighth of an inch more that the choke plate could open, but the rod was not pulling it all the way open.
Thanks.
 
PM me your email and I will send you the tuning article by Tom Quaid.
 
lyndondb said:
The six pack is a great set up when "set up" correctly and tuned correctly. Exhilarating ride!
Click to expand...
YES! Having the 2 outboard carbs come in is WAY more impressive than any secondary of any 4bbl I have experienced.
 
lyndondb said:
PM me your email and I will send you the tuning article by Tom Quaid.
Click to expand...
I have seen it. I'm not completely sold on everything he says, but he sure is adamant about his exact process.
PM sent.
 
lyndondb said:
Also as you can tell from the reply's there are a number of places that can cause this problem. Make no mistake the six pack idles on all three carburetors. If you have the fast idle solenoid make I would disable it first. As previously stated make sure the linkeage for the outboard carburetors are adjusted so that they are fully closed at idle. Ensure that the throttle linkage is correct for a six pack (four barrell hardware cable etc will not work properly). Make sure the vacuum lines on the passenger side are correct. CAUTION!! Incorrect placement of the vacuum lines can pull the out board carbs full open. Any doubt get a picture (I can send you one) before monkeying with these. If this is all correct I would check for vacuum leaks. There is an article on this site posted recently that tells how to on six packs. Read and adhere. Good Luck
Click to expand...
##########################
Do you have a detail of all vacuum line as where they go? Or know who can provide
 
Does anyone have have a detail of all vacuum line as where they go for the 440 6 pack Or know who can provide one?
 
I will check my 1970 Service Manual for a diagram and see if I can take some pix Monday.
I am ridiculously busy, but I will try.
 
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