edelbrock carb tuning? - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 09-01-2003, 10:52 PM
opeysgarage's Avatar
Member
 
Join Date: Sep 2003
Location: San Diego for now.
Age: 34
Posts: 34
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
edelbrock carb tuning?

I have a fresh 350 stroked and bored to 383 with edle brock rpm heads and intake manifold. I have a 750cfm edlebrock 4 barrel on it. I am having a hell of a time tuning it in. It idles rough and the idle drops significantly from park to in gear. It also dies or stumbles if I take a hard "u turn like" turn. I tried the instructions from edlebrock but to no good use. By their instructions I have the idle adjustment screws at the front of the carb, turned almost completely in.
If anyone knows anything, please help as soon as possible..
Thanks..
Opey

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 09-01-2003, 11:19 PM
ThrouHerEyes's Avatar
Registered User
 
Join Date: Sep 2003
Location: Plattsburgh New York
Age: 28
Posts: 9
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Could be a break or hole in your muffler or exaust.. my fried's 240sx does the same and it ended up being a break in the welding to the muffler.. start it up over some sand or dirt and look under the car or have it in a driveway and get on the ground if you see that there is air pushing the dirt/sand or feel heat or air from under the car that is your problem...also if you can smell the exaust fumes inside while idleing that is another sign
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 08-15-2006, 02:12 PM
woundbroom's Avatar
Registered User
 
Join Date: Nov 2003
Location: New Jersey
Age: 63
Posts: 25
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
750 edlebrock

opey,
I have a 750 edelbrock in my garage (notice location) and cant figure the damn thing out either. I reset the floats, changed jets, changed metering rods up and down and mine did the same things yours is doing.I paid near 400 for the carb and set-up kit to no avail.. Checked on line about the carb and we are definitley not alone with these problems. Steve
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 08-15-2006, 04:24 PM
DOUBLEDICK's Avatar
Member
 
Last photo:
Join Date: Jul 2005
Location: Henderson Nevada
Age: 54
Posts: 308
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
On my 750 I had a hard time dialing it in.I finally put a vacuum gauge to th manifold And found I had to go to the lighter springs under the metering rods as it would not drop into the lean position at idle.I also hooked a tach(my alt. tester has a tach function) to the distributor so I could see the effect of the metering screws as the difference in rpm was so subtle I could not tell by ear.I had a stumble at initial acceleration and it went away when I changed the springs to match my vacuum and adjusted the metering screws.I also had to change to a vacuum advance distributor as my mechanical advance left the timing retarded to far at idle.The vacuum advance has my engine at about 16 degrees at idle were my mechanical advance had me at the 4 degrees of initial timing at idle.Good luck hope this helps you find the sweet spot in your 750.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 08-15-2006, 07:16 PM
Registered User
 
Last photo:
Join Date: Feb 2006
Location: Chicago
Posts: 11
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I had alot of problems getting mine setup too. This is on a new ZZ4.

Part# was edelbrock #1411-750cfm.

First of all, this carb is jetted way lean out of the box. Buy the tuning kit.

I ended up with:

mains: .113
secs: .110
needles: 073 x 037

These settings correspond to #21 on the model 1407/1410 chart--off the scale rich on the 1411 chart.

Pump rod in the top bracket hole, silver (8Hg) metering rod springs.

12-14 degrees BTDC
recurved distrib, light springs so you're all in by 3500 or so.
Disconnected vacuum retard.

Still going a little lean around 2000-3000, but comes on hard after that. Might be room to even go up another jet size from there and 'needle out'.

I hope this helps get you in the ballpark.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 08-15-2006, 07:29 PM
97Z28's Avatar
NTI Grad.
 
Last photo:
Join Date: Jul 2005
Location: Chardon, Ohio
Age: 32
Posts: 607
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
this is why i like BG, Holley or demon carbs. i've known way too many people that had problems with edelbrock carbs. And if you say..."well if you knew how to tune your carb better the edelbrock works fine". that is a load of crap. i've talked to a few edelbrock techs that even have problems tuning them.

my advice to you... go to a car show and find somebody with a similar setup as what you have with an edel. carb and talk to him/her about tuning it. or, you could just sell it on ebay and use the money for a new holley or BG.
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 08-15-2006, 08:45 PM
Derkyb's Avatar
Member
 
Last photo:
Join Date: Jan 2005
Location: okc, ok
Age: 39
Posts: 229
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
First do you have a stall converter to match your cam? I've had a few edelbrocks on my 355ci one being a large 750. I tuned it to run ok wide open but idle and part throttle was a mess. I finally put on a 600 jetted it up and it runs 100x better. Your not going to be happy until you put on a smaller carb. heres a link with a calculator, I think you will find you need alot smaller carb than you think. http://www.classictruckshop.com/garage/shopmathcfm1.asp
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 08-17-2006, 09:06 AM
Registered User
 
Join Date: Aug 2006
Location: California
Posts: 16
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
the edelbrock carbs have a lean off idle problem, i only recommend using a 650 or lower cfm edelbrock on any application because of this but:

the idle channel restriction (ICR) is too small for the idle system so the idle system runs out of fuel flow before you get into the main circuit. look in the carb owners manual and you can see where it is. we remove the brass restriction over the ICR and then enlarge the ICR a few thousands of a inch at a time to make the idle and off idle system more active. this workd very well on the 600 performer and 650 cfm thunder but on the 750 it only helps since the rest of the idle system passages are too small. these changes have been done to the 800 cfm edelbrocks but it is not enough to solve the problem (in my opinion)if you want to see pictures of this the july 2006 issue of Corvette Fever has a article called tuning to perfection with more detail in it.

you can see this lean at off idle condition with tools such as a wide band oxygen sensor based air/fuel meter or a 5 gas exhaust gas analyzer.

i hope this helps henry @ oles carb
Reply With Quote Quick reply to this message

Recent Engine posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -6. The time now is 04:14 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.