Re: Holley carb driving me nuts!
[Re: buildanother]
#1950445
11/13/15 12:28 PM
11/13/15 12:28 PM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
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no vac leak from a base gasket. float levels correct. no restricted inline filter hidden in the inlet fitting. wouldn't think a SA would be lean but might bump up the primary jets 4 sizes for a quick test.
live every 24 hour block of time like it's your last day on earth
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Re: Holley carb driving me nuts!
[Re: MikeT]
#1950457
11/13/15 12:53 PM
11/13/15 12:53 PM
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Joined: Jan 2003
Posts: 5,444 Indiana
YO7_A66
master
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master
Joined: Jan 2003
Posts: 5,444
Indiana
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""but as the rpms come up ( I don't have my tach hooked up but about 2500-3500 rpms) engine goes flat""
At this rpm range, you are cruising on the MAIN CIRCUIT. Test larger main jets and see if that makes a difference. If your mains are too lean, you will have a stumble in this range when changing rpms.
1970 YO7 A66 [Canadian Export] F8 Challenger 340 (Currently in shop for stroker assy.)
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Re: Holley carb driving me nuts!
[Re: YO7_A66]
#1950499
11/13/15 02:29 PM
11/13/15 02:29 PM
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Joined: Jan 2003
Posts: 2,094 central texas
krautrock
top fuel
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top fuel
Joined: Jan 2003
Posts: 2,094
central texas
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""but as the rpms come up ( I don't have my tach hooked up but about 2500-3500 rpms) engine goes flat""
At this rpm range, you are cruising on the MAIN CIRCUIT. Test larger main jets and see if that makes a difference. If your mains are too lean, you will have a stumble in this range when changing rpms. agree with this. jet it up atleast 4 jets sizes on the primary side (doubt it has jets in the secondary side). the correct power valve will also help tremendously with part throttle high load driving. start there with a PV rating half of what yr idle vacuum is. my truck idles at 18", i went from a 6.5 to 8.5 PV and it made it much more pleasurable to drive. basically, get the PV right, then get yr idle off idle mix right. then work on the primary jets. then work on yr secondary spring rate...
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Re: Holley carb driving me nuts!
[Re: Morty426]
#1951072
11/14/15 02:38 PM
11/14/15 02:38 PM
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Joined: Jul 2004
Posts: 19,317 State of confusion
Thumperdart
I Live Here
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I Live Here
Joined: Jul 2004
Posts: 19,317
State of confusion
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Do you have a possible linkage issue? Since the other carbs work I would focus on what's different about this carb.
What`s wrong is that it`s a vac sec. carb........I don`t like vac. controlling my secondary enrichment ever.
72 Dart 470 n/a BB stroker street car `THUMPER`...Check me out on FB Dominic Thumper for videos and lots of carb pics......760-900-3895.....
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Re: Holley carb driving me nuts!
[Re: 451Mopar]
#1951229
11/14/15 08:43 PM
11/14/15 08:43 PM
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Joined: Jul 2010
Posts: 42 Ca
MikeT
OP
member
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OP
member
Joined: Jul 2010
Posts: 42
Ca
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I had a 670 Truck Avenger that had metal left over from machining the fuel blocks in the channels behind the jets (so much for quality control?) I would pull the carb apart and remove all the jets, and then blow out all the channels and air bleeds, and/or run a small wire through them to make sure there is nothing blocking the passages in the carb. I have had two avenger carbs, and both were tuned pretty lean in the idle and power valve restrictions. I think they were around 0.025" diameter? I think went to about 0.028 or 0.030" with pin drills and that really helped the idle transition and power under load.
Ill open her up a take a look at the secondary jets and metering block. I did try wiring the secondaries shut and took her for a test drive. After good off idle accel I hit a flat spot, stumble and then I am able to continue to go up in the rpms, unlike before. Seems better, but not sure what to make of this? I have the stiffest spring(black) installed. Should I go down in secondaies jets?
Last edited by MikeT; 11/14/15 08:44 PM.
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