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04-02-2003, 11:29 AM
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CC Member
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Join Date: Sep 2001
Location: Lewisville, TX,
Posts: 50
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Not Ranked
Edelbrock Carb tuning
I have an Edelbrock 1406 (600cfm) carb that I am trying to tune. I currently have .073 x .047 metering rods, .098 primary and .098 secondary Jets and the 4in Yellow Step-Up springs.
Heavy acceleration from a standing stop is very sluggish. I have moved the external setting for the Accelerator pump, and it does not get better (currently set on center hole). Rolling acceleration seems to be good. Timing is set to about 12 deg. before TDC and I just installed a Pertronix Ignitor.
What changes can I make to help?
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04-02-2003, 02:46 PM
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CC Member
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Join Date: Mar 2002
Location: so cal,
Cal
Cobra Make, Engine: I used to fix them for a living
Posts: 2,563
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Not Ranked
remove carb, place in box, install holley.
__________________
In a fit of 16 year old genius, I looked down through the carb while cranking it to see if fuel was flowing, and it was. Flowing straight up in a vapor cloud, around my head, on fire.
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04-02-2003, 03:06 PM
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CC Member
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Join Date: May 2002
Location: Beaufort,
SC
Cobra Make, Engine: Classic Roadsters '66 427 Replica-SOLD
Posts: 299
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Not Ranked
Put in your 8" step up spring and move accelerator pump to the innermost hole....Max squirt!!
This should help a lot!! If you have other metering rods try to go richer in the power mode.
Email me and I'll share my experiences getting mine right!!
It may not give the last HP the Holley will but it sure is less trouble once you richen it up!!!
Do keep in mind that they are set up very lean from the factory for "smog" reasons.
Good Luck,
Jack  |
04-02-2003, 06:01 PM
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CC Member
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Join Date: Dec 2001
Location: San Diego,
CA
Cobra Make, Engine:
Posts: 2,977
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I have the same carb on my truck and had the same problem.
I moved to the 7" spring, (heavier spring means more vacuum required to stay in cruise mode so the idle to WOT is quicker to power mode), went to the innermost hole on the pump, and richer power mode on metering rod and that cleared up most of it. It seemed to improve a little be retarding the timing a couple of degrees as well. I now run at an initial timing of 10 degrees BTDC and max out at 34 degress BTDC at 2400 RPM.
Now it only chokes if it sits idling for a while just prior to jumping on it.
Sorry Mr. Fixit I'd rather give up a few horsepower on the top end and not have to replace power valves every 6 months.
__________________
Remember, It's never too early to start beefing up your obituary.
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04-02-2003, 06:25 PM
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CC Member
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Join Date: Aug 2002
Location: Dalton,
GA
Cobra Make, Engine: West Coast 460, Performer Cam & Intake, Edelbrock 750cfm Carb
Posts: 256
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Not Ranked
Hmmmmmmm,
Just the reverse problem with my 750. Run so rich out of the box your eyes would water a block away with soot out the sidepipes. 2 buddies with 600's with the same symtom. Have leaned mine down 2 steps and then got the hesitation. I believe it has to do with the transition circuit. Am going to try an old trick after I pull the carb and check the butterfly position at idle. Two thirds of the idle opening should be exosed. If not a 3/32 hole through each butterfly is supposed to fix that.
** Someone stop me if they've been down this road. **
__________________
 "Nobody gets to see the Wizard. Not Nobody. Not Nohow.
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04-02-2003, 07:00 PM
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CC Member
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Join Date: Dec 2000
Location: Los Angeles,
CA
Cobra Make, Engine: E.R.A. FIA #2088 1964 289 w/Webers
Posts: 2,151
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Not Ranked
Quote:
Originally posted by Mr.Fixit
remove carb, place in box, install holley.
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I second that 
__________________
Hyde D. Baker
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04-02-2003, 07:46 PM
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CC Member
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Join Date: Aug 2000
Location: Chicago,
IL
Cobra Make, Engine: ERA 454 S.O.
Posts: 1,684
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Not Ranked
__________________
Jeff
“If you can make black marks on a straight from the time you turn out of a corner until the braking point of the next turn, then you have enough horsepower.”
Mark Donahue
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04-04-2003, 07:39 AM
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CC Member
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Join Date: Mar 2002
Location: so cal,
Cal
Cobra Make, Engine: I used to fix them for a living
Posts: 2,563
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The power valve myth is just that, a myth. Any holley made in the last 15 years has that problem solved, if it doesn't, than a quick check ball install to the baseplate is all it takes. How often does your motor backfire through the carb anyway?
__________________
In a fit of 16 year old genius, I looked down through the carb while cranking it to see if fuel was flowing, and it was. Flowing straight up in a vapor cloud, around my head, on fire.
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04-04-2003, 08:34 AM
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Senior Club Cobra Member
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Join Date: Jul 2000
Location: Chilliwack,BC,
BC
Cobra Make, Engine: F5 Roadster
Posts: 1,419
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Not Ranked
Hi,
Someone has changed the factory settings, go back to them.
.098 primary jets
.095 secondary jets
.075 x .047 metering rod
your secondaries are way too rich with the bigger jet .
go back to the stock metering jet also.
turn front air screws all the way in and back them out 1 1/2 turns to start, turning them out richens up the mixture.
make sure you have decent vaccum or look for a leak.
good luck,
Perry.  |
04-04-2003, 06:44 PM
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CC Member
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Join Date: Sep 2001
Location: Lewisville, TX,
Posts: 50
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As it turns out (after a call to Edelbrock) I was close. All I needed to change was to the 7 in spring. Runs great now.
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04-05-2003, 03:15 AM
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CC Member
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Join Date: Nov 2000
Location: Houston,
Tx
Cobra Make, Engine: Unique FIA
Posts: 2,064
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Not Ranked
C_forshaw,
Does the carb you have handle really aggressive throttling in 2nd and 3rd gear without stumbling? What intake are you running?
Steven 
__________________
All my ex's live in Texas
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04-06-2003, 06:11 AM
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CC Member
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Join Date: Sep 2001
Location: Lewisville, TX,
Posts: 50
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There is no stumble on agressive throttle in any gear. I am running a Weiand intake.
Chuck
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04-06-2003, 08:37 AM
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CC Member/Contributor
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Join Date: Feb 2000
Location: Greenville,
SC
Cobra Make, Engine: 70 Shelby convertible, ERA-FIA, 66 mustang convertible, mystery Ford powered 2dr convertible
Posts: 12,640
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Not Ranked
Me too....have to get up earlier in the morning to play the heavy these days......
Bill S.
__________________
Instead of being part of the problem, be part of a successful solution.
First time Cobra buyers-READ THIS
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04-06-2003, 08:41 AM
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CC Member/Contributor
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Join Date: Feb 2000
Location: Greenville,
SC
Cobra Make, Engine: 70 Shelby convertible, ERA-FIA, 66 mustang convertible, mystery Ford powered 2dr convertible
Posts: 12,640
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Not Ranked
Now, with that said, tell us a little more about your motor....
year of the block
year of the heads
Compression ratio
Cam profile
Type of intake
Automatic or stick shift
All will play a factor in how your particular carb should be set up. However, I can tell you from experience that the Edelbrock carbs do not lend themselves to performance, but more to the "bolt on and forgetaboutit crowd".........I sell them (Holley, Edlebrock, Barry Grant, Dan Best, etc), and have seen far too many replaced with a generic (yet quite tunable) Holley 08777C (650 double pumper), tuned properly (usually on a chassis dyno), that make more power, with better reliability than the Edlebrock units............
Bill S.
__________________
Instead of being part of the problem, be part of a successful solution.
First time Cobra buyers-READ THIS
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04-06-2003, 08:57 AM
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CC Member
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Join Date: Sep 2001
Location: Lewisville, TX,
Posts: 50
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Not Ranked
I have a 1980 302 block (EOAE) with a Weiand of intake and Toploader 4sp (RUG-E)- wide ratio tranny out of '67 Mustang. I don't know to much more about the engine. I have a date with the dyno is a few weeks. That will tell me a lot more about the engine.
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04-06-2003, 10:04 AM
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CC Member/Contributor
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Join Date: Feb 2000
Location: Greenville,
SC
Cobra Make, Engine: 70 Shelby convertible, ERA-FIA, 66 mustang convertible, mystery Ford powered 2dr convertible
Posts: 12,640
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Not Ranked
I suggest making sure that the dyno is equipped with a wife band O2 sensor, and that your bring along someone who can tune your carb while it is up there....You want as close to a 14:1 air fuel ratio as possible............
Bill S.
__________________
Instead of being part of the problem, be part of a successful solution.
First time Cobra buyers-READ THIS
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04-06-2003, 07:07 PM
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CC Member
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Join Date: Nov 2000
Location: Houston,
Tx
Cobra Make, Engine: Unique FIA
Posts: 2,064
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Not Ranked
Bill,
Can you elaborate a little on your experiences as to the Edelbrock carbs? I ask, because I have not been able to eliminate the
stumble my friend's 347. I have tuned it per their book, experimenting to the extremes of the jetting and spring combos. We
dyno tuned it to around 14:1 with good transitions.
I suspect the carb is just not capable of handling really aggressive driving due to the combination of mechanical linkage to the
2ndrys and it having no 2ndry accelerator pump. (it just seems the air door design can not handle it) I posed this question to the
tech rep at Edelbrock and he danced around the question. I have also noticed they now make a version of the AVS carb. Will
they phase out the current offering due to it's limitations? Being in the business, what are you hearing?
Thanks
Steven
__________________
All my ex's live in Texas
Last edited by Steve R; 04-06-2003 at 07:24 PM..
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