Sixpack / Holley Idle Curuit tuning question:
#2060466
04/23/16 09:15 PM
04/23/16 09:15 PM
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Joined: Jul 2005
Posts: 712 California
BigDaddy440
OP
super stock
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OP
super stock
Joined: Jul 2005
Posts: 712
California
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I've read a lot on this topic, but I'm still learning here's my question:
I have new a 440 with decent sized cam and a NEW sixpack set up. Car starts up quickly, runs at 180-185 degrees F and shuts off clean. Mechanically sounds like a beast.
CAMSHAFT: 241/247@.050" .540/.540 lift. (hyd.flat tappet)
I'm trying to get the center carb to idle "within the idle circuit" but I'm having a little trouble.
When I put a vacuum gauge on the "spark port" of center carb at idle, it's still pulling vacuum...so it seems I need to turn the idle adjustment screw out to close throttle blades more...but if I did this enough to get a zero reading on the gauge the engine would die as it cant idle at 600rpm.
I've advanced the timing to the point where I'm not sure I should go much more...about 22-24 degrees INITIAL at 850-900 rpm. I was hoping to stay about 12-15 initial.
I started the idle circuit screws (center carb,both sides) at 1.5 turns out and tried to turn them out a bit more and watched the vacuum gauge (this time on manifold vacuum) and the needle just moves around with the slight fluctuations of the idle. Basically, I'm not confident in the reading on the gauge with it moving around.
What should I be doing with the idle circuit screws? How should they effect idle? Is it too early to adjust them knowing I'm not running 100% off the idle circuit on the center carb?
I was hoping I wouldn't have to modify the throttle blades (drill holes in them etc) to get the car idle within the idle circuit, so I'm looking for answers.
Advice?
Thanks!
1969 A12 Roadrunner 1970 Plymouth Cuda 1968 Dodge Dart
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Re: Sixpack / Holley Idle Curuit tuning question:
[Re: BigDaddy440]
#2060473
04/23/16 09:32 PM
04/23/16 09:32 PM
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Joined: Nov 2011
Posts: 2,154 Its a TRAP!
DARTH V8Я
Oh No!! I just had a moron attack!
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Oh No!! I just had a moron attack!
Joined: Nov 2011
Posts: 2,154
Its a TRAP!
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iirc there's an adjustment on the secondaries to open the throttle blades a bit. Then you can drop idle idle speed screw on the center carb.
When it takes more than a sweet mullet to prove you rule at the trailer park..
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Re: Sixpack / Holley Idle Curuit tuning question:
[Re: DARTH V8Я]
#2060479
04/23/16 09:36 PM
04/23/16 09:36 PM
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Joined: Jul 2005
Posts: 712 California
BigDaddy440
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super stock
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OP
super stock
Joined: Jul 2005
Posts: 712
California
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Awesome...now I just have to find them! Thank you, that just may solve my issue. -Dan
1969 A12 Roadrunner 1970 Plymouth Cuda 1968 Dodge Dart
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Re: Sixpack / Holley Idle Curuit tuning question:
[Re: BigDaddy440]
#2060497
04/23/16 10:28 PM
04/23/16 10:28 PM
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Joined: Jul 2005
Posts: 712 California
BigDaddy440
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super stock
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OP
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Ok, I found those little adjustment screws on the outboards. Obviously you can only adjust the front outboard idle screws and apparently have to remove the rear outboard to adjust it.
By adjust them out a little, the rpm did increase, but I didn't do it too much as I'm sure I'm leaning out the mixture when I do this.
I will remove rear outboard and adjust them out just a tad too (like the front) and see if I can get fully into the idle circuit.
I don't want to lean out the mixture too much either, as I currently have stock jetting and might be on the lean side already. (considering my cam, heads, compression etc).
1969 A12 Roadrunner 1970 Plymouth Cuda 1968 Dodge Dart
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Re: Sixpack / Holley Idle Curuit tuning question:
[Re: BigDaddy440]
#2060503
04/23/16 10:40 PM
04/23/16 10:40 PM
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Joined: Jan 2005
Posts: 4,243 Charlotte, North Carolina
sgcuda
master
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master
Joined: Jan 2005
Posts: 4,243
Charlotte, North Carolina
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You can make up for the leaning out with the center carb mixture screws. See if you can get your idle speed and ported vacuum where you want it. Why do you think you need lower vacuum than you already have on the vacuum port? What is wrong with the way it runs, now?
[image][/image]
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Re: Sixpack / Holley Idle Curuit tuning question:
[Re: sgcuda]
#2060540
04/23/16 11:44 PM
04/23/16 11:44 PM
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Joined: Jul 2005
Posts: 712 California
BigDaddy440
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super stock
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OP
super stock
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Posts: 712
California
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Why do you think you need lower vacuum than you already have on the vacuum port? What is wrong with the way it runs, now? I've read that on the spark port, (not intake vacuum) if you are pulling vacuum on the gauge, than you're not completely in the idle circuit on the center carb. As I close the throttle blades on the center with the idle adjust screw, the vacuum on the spark port continues to decrease. Once I have the engine idling where I want it with the spark port vacuum reading at zero, then I'll know I'm idling on the carbs idle circuit.
1969 A12 Roadrunner 1970 Plymouth Cuda 1968 Dodge Dart
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Re: Sixpack / Holley Idle Curuit tuning question:
[Re: BigDaddy440]
#2060543
04/23/16 11:51 PM
04/23/16 11:51 PM
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Joined: Aug 2003
Posts: 43,315 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,315
Bend,OR USA
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You need to adjust the outer carbs. idle mixtures gently in all the way and then back the needles out 1/3 to 1/2 turn out from bottom out (that means removing the rear carb. to work on it or remove the front and center carbs to work on the rear idle mixture screws ) Make sure to disconnect the secondary linkage and adjust that so that both sets of butterflys(front and rear carbs.) are closed at idle with the center carb butterflys closed all the way also Then set the center idle mixture screws out from 1 1/2 to 2.0 full turns and see if that helps My old low deck six pak would idle that way, same thing with the replacement 1971 440 carbs I bought to compare to my original 1970 440 six pak carbs.
Last edited by Cab_Burge; 04/25/16 03:32 AM.
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Sixpack / Holley Idle Curuit tuning question:
[Re: BigDaddy440]
#2060704
04/24/16 10:49 AM
04/24/16 10:49 AM
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Joined: Feb 2005
Posts: 4,321 Prospect, PA
BSB67
master
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master
Joined: Feb 2005
Posts: 4,321
Prospect, PA
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Ok, I found those little adjustment screws on the outboards. Obviously you can only adjust the front outboard idle screws and apparently have to remove the rear outboard to adjust it.
By adjust them out a little, the rpm did increase, but I didn't do it too much as I'm sure I'm leaning out the mixture when I do this.
I will remove rear outboard and adjust them out just a tad too (like the front) and see if I can get fully into the idle circuit.
I don't want to lean out the mixture too much either, as I currently have stock jetting and might be on the lean side already. (considering my cam, heads, compression etc).
Out is richer, not leaner.
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Re: Sixpack / Holley Idle Curuit tuning question:
[Re: BigDaddy440]
#2060744
04/24/16 12:13 PM
04/24/16 12:13 PM
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Joined: Jun 2003
Posts: 9,225 Charleston
sixpackgut
Drag Week Mod Champion
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Drag Week Mod Champion
Joined: Jun 2003
Posts: 9,225
Charleston
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All you guys are misunderstanding his question.
His problem is, the engine is not getting enough air to run on the idle circuits alone. He is opening the center throttle blade to far to get idle rpms higher but then he is on the transfer circuit. You can not adjust the outboard throttle blades to allow more air at idle like you can on the secondary throttle blades of a DP. This is a common problem with six pack setups
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Re: Sixpack / Holley Idle Curuit tuning question:
[Re: crackedback]
#2061180
04/25/16 01:24 AM
04/25/16 01:24 AM
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Joined: Jul 2005
Posts: 712 California
BigDaddy440
OP
super stock
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OP
super stock
Joined: Jul 2005
Posts: 712
California
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No fricken way does that engine run close to right with 12-15* initial. Get rid of that notion. My 340 with a 241 at .050 cam has 24* initial. Starts up in 100+ degree weather with a flick of the key.
It's going to want in the 20's, where you are. Let the engine tell you, not some notion or desired number that you feel is correct. Thank you for that, that may be the case. It fires up instantly right now and sounds great, so my timing might be very close to being where it needs to be. Thanks for the great info here guys! I feel like I have the info now to dial these suckers in!
1969 A12 Roadrunner 1970 Plymouth Cuda 1968 Dodge Dart
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