6 pack metering block question
#2447615
02/06/18 08:59 PM
02/06/18 08:59 PM
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Joined: Jul 2006
Posts: 4,179 California
mickm
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So the idle on my car is at 15:1 AFR, and the screws are 2 1/2 - 2 /34 of the way out. I have the metering block over at a long time Holley guys shop, and he was going to enlarge the passages by .003, but they are not where they usually are on these metering blocks. To get to the passages, is it through the brass plugs on the bottom of the block? And if so, it looks like those are not going to come out easily. Where do I get replacements?
And is this what I need to do to be able to richen it up at idle, and have the screws in a reasonable place?
Last edited by mickm; 02/06/18 09:00 PM.
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Re: 6 pack metering block question
[Re: mickm]
#2447639
02/06/18 09:34 PM
02/06/18 09:34 PM
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Joined: Jan 2003
Posts: 1,379 Houston,Tx.
Lee446
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Mick, have you tried adjusting the mixture screws in the baseplates of the end carbs? Backing them out maybe 1/8 turn each will make a big difference and take some of the load off your center carb. I have set up more than a few 6 paks and even with big cams, I've never had to open idle passages in the center carb. Good luck!
Last edited by Lee446; 02/06/18 09:37 PM.
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Re: 6 pack metering block question
[Re: Lee446]
#2447694
02/06/18 10:22 PM
02/06/18 10:22 PM
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Joined: Jul 2011
Posts: 960 Chicago
PurpleBeeper
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Mick, have you tried adjusting the mixture screws in the baseplates of the end carbs? Backing them out maybe 1/8 turn each will make a big difference and take some of the load off your center carb. I have set up more than a few 6 paks and even with big cams, I've never had to open idle passages in the center carb. Good luck! VERY good advice. Also, I am not aware of any metering block idle mixture passages under the metering block behind plugs??? There are main circuit passages behind the power valve at 3 o'clock & 9 o'clock that can be enlarged per the old Direct Connection book, but I don't recommend doing it. There are also some holes up in the top corners (name?) that can be enlarged too, but again I don't recommend it. I know you have that big stroker hemi six pack, so maybe consider Promax parts instead of modifying stock pieces. You can get adjustable metering bodies & adjustable metering plates.... but try the outboard idles screws first like Lee says. THOSE are behind lead plugs on the front of the baseplates for the outer carburetors. Hope this helps.
Last edited by PurpleBeeper; 02/06/18 10:23 PM.
70 Roadrunner convt. street car
440+6, NOS, 4-spd, SS springs
'96 Mustang GT convt. street car
'04 4.6 SOHC, NOS, auto, lowered
"Officer, that button is for short on-ramps"
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Re: 6 pack metering block question
[Re: Sixpak]
#2447727
02/06/18 11:11 PM
02/06/18 11:11 PM
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Joined: Jul 2006
Posts: 4,179 California
mickm
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Mick, have you tried adjusting the mixture screws in the baseplates of the end carbs? Backing them out maybe 1/8 turn each will make a big difference and take some of the load off your center carb. I have set up more than a few 6 paks and even with big cams, I've never had to open idle passages in the center carb. Good luck! Best idle on a small block Sixpak setup with an XE268 cam ended up with the mixture screws on all 3 carbs out 1 5/8 turns. Covering the corresponding air bleed one at a time will tell you which direction to go with the mixture screw. Never had to drill anything. I have done that following the writeup from Dayclona, and have the end carbs, as far as I can tell, adjusted properly, in that when I cover the air bleeds one at at time, there is no change in the idle. There was when I first put the carbs on, so I know there was a change.
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Re: 6 pack metering block question
[Re: Cab_Burge]
#2447775
02/07/18 12:04 AM
02/07/18 12:04 AM
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Joined: Jul 2006
Posts: 4,179 California
mickm
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So the idle on my car is at 15:1 AFR, and the screws are 2 1/2 - 2 /34 of the way out. What is wrong with that I like to see above 14.5 AFR at idle when warm or hot to help keep the plugs clean My old pump gas Duster 6 pack set up ran at or above 15.2 AFR at idle and low part throttle high manifold vacumme cruise up to 2300 RPM That rascal flat rocked Damn good question! It started with me asking a couple of very experienced engine builders why my car stinks so bad at idle. I thought running rich would make it stink, an they both said, "because it's running too lean." So, in an attempt to richen it up to see where that would get me, and knowing that for a Holley, almost 3 turns out on the idle screws is not optimal, I was attempting to get the idle screws to a more normal position, to give a range of control over the mixture.
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Re: 6 pack metering block question
[Re: mickm]
#2447970
02/07/18 12:47 PM
02/07/18 12:47 PM
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Joined: Mar 2007
Posts: 3,287 West Coast, USA
jbc426
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[/quote]
Damn good question! It started with me asking a couple of very experienced engine builders why my car stinks so bad at idle. I thought running rich would make it stink, an they both said, "because it's running too lean." [/quote]
My EFI car smelled bad at idle as well. It has a pretty healthy roller cam in it. That was with an oxygen sensor feeding back to the ECM.
I welded a pair of metal matrix, racing catalytic converters on it and the problem was solved. It didn't affect the power output either.
1970 Plymouth 'Cuda #'s 440-6(block in storage)currently 493" 6 pack, Shaker, 5 speed Passon, 4.10's 1968 Plymouth Barracuda Convertible 408 Magnum EFI with 4 speed automatic overdrive, 3800 stall lock-up converter and 4.30's (closest thing to an automatic 5 speed going)
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Re: 6 pack metering block question
[Re: Cab_Burge]
#2448067
02/07/18 04:23 PM
02/07/18 04:23 PM
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Joined: Jul 2011
Posts: 960 Chicago
PurpleBeeper
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To see if enrichening helps the idle air fuel ratio helps you gain better control of the idle mixture try using some very thin wires formed like a J stuck upside down into all six idle air bleeds Let us know your results This is an interesting idea!
70 Roadrunner convt. street car
440+6, NOS, 4-spd, SS springs
'96 Mustang GT convt. street car
'04 4.6 SOHC, NOS, auto, lowered
"Officer, that button is for short on-ramps"
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Re: 6 pack metering block question
[Re: mickm]
#2448068
02/07/18 04:27 PM
02/07/18 04:27 PM
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Joined: Jul 2011
Posts: 960 Chicago
PurpleBeeper
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super stock
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WOW! GREAT thing you called Holley.... good job.
70 Roadrunner convt. street car
440+6, NOS, 4-spd, SS springs
'96 Mustang GT convt. street car
'04 4.6 SOHC, NOS, auto, lowered
"Officer, that button is for short on-ramps"
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Re: 6 pack metering block question
[Re: mickm]
#2448150
02/07/18 07:22 PM
02/07/18 07:22 PM
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Joined: Mar 2011
Posts: 3,102 Michigan
A727Tflite
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The stench from burning lean doesn't smell anywhere near the same as burning rich.
Burning rich burns your eyes where lean just stinks - it even smells hot - has a "burning" smell but doesn't burn your eyes. At least the ones I have been involved on.
Last edited by Transman; 02/07/18 07:22 PM.
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Re: 6 pack metering block question
[Re: mickm]
#2448332
02/08/18 02:42 AM
02/08/18 02:42 AM
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Joined: Feb 2004
Posts: 7,196 Harrisburg, Pa.
screamindriver
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Well, here's a fun one!
I just got a call from Holley, and apparently some of these metering blocks are making it down the line, WITHOUT the idle restrictor passage being drilled out! And mine is one of them...
So, they are sending me a new metering block, and I'll take it from there.
Sigh... So much for Holley quality control...You wouldn't think something like this would ever leave the factory...
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Re: 6 pack metering block question
[Re: krautrock]
#2448510
02/08/18 02:30 PM
02/08/18 02:30 PM
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Joined: Jul 2006
Posts: 4,179 California
mickm
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when were the carbs originally bought? bought new, last year or two.
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Re: 6 pack metering block question
[Re: A727Tflite]
#2448599
02/08/18 05:13 PM
02/08/18 05:13 PM
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Joined: Jul 2006
Posts: 4,179 California
mickm
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The stench from burning lean doesn't smell anywhere near the same as burning rich.
Burning rich burns your eyes where lean just stinks - it even smells hot - has a "burning" smell but doesn't burn your eyes. At least the ones I have been involved on. your lean description is what mine is like...
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