Edelbrock.....super rich at idle?? Are the metering rods up? - 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 04-21-2005, 10:51 PM
wickster's Avatar
Member
 
Last photo:
Join Date: Mar 2004
Location: Calgary, Alberta, Canada
Posts: 139
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Edelbrock.....super rich at idle?? Are the metering rods up?

I read all the posts on this issue but none really have the answer?

350 SBC, CompXE268 cam...brand new rebuild.

Timing is at 12 degrees and I am getting 13 in vacuum at about 800 rpm. That is the most vaccum I can get by adjusting the idle screws. Car seems to run great at all speeds but still running way too rich at idle...my eyes burn in the garage.

Where do I start? Is it possible that the metering rods are in the "power mode" at idle? I changed the springs last year in my old 327...but the fuel washed the color out and I don't know what they are. Any suggestions on which spring to use?

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 04-21-2005, 11:46 PM
Member
 
Last photo:
Join Date: Mar 2003
Location: Bakersfield, CA
Posts: 397
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
What carb do you have? In case of Edelbrock, here is online manual + some recommendations from the author:
http://www.telusplanet.net/public/gi...delbrock_1.htm

Regards!
Denis
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 04-22-2005, 06:15 AM
cboy's Avatar
Member
 

Last journal entry: Finished
Last photo:
Join Date: Jan 2004
Location: Atwater, CA
Age: 69
Posts: 3,915
Wiki Edits: 0

Thanks: 0
Thanked 2 Times in 2 Posts
If you have the other springs from the E-brock spring kit, you should be able to tell which ones you have installed by laying them out with the others. There is a variation in size as well as color. I could be wrong about this but I doubt it is your springs that are causing the rich condition at idle. My understanding is the springs control rod movement under throttle - something like back pressure to the vacuum forces - and the rods should always return to the idle position. Have you pulled the rods and cleaned them up real good? Maybe on of them is sticking in the bore. Another possibility off the top of my head is that you somehow got a mismatch between your rods and your jets. This would be possible if you (or a prior owner) has done a lot of different tuning on the carb. Each jet size will only work with a couple of rod sizes (these matche ups are shown in the on line manual).
__________________
Always learning...and sharing what I've learned. The Scratch-Built Hot Rod.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 04-22-2005, 07:49 AM
wickster's Avatar
Member
 
Last photo:
Join Date: Mar 2004
Location: Calgary, Alberta, Canada
Posts: 139
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Sorry...carb is an Edelbrock 1406 (600 CFM)
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 04-22-2005, 09:28 AM
Member
 
Last photo:
Join Date: Mar 2003
Location: Bakersfield, CA
Posts: 397
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
wickster,
go to that link I posted and find the chart for 600cfm carb. Take your carb off the intake, open it up (easy - 5 minutes) and take a note of which primary and secondary jets you are using. Write down which metering rods you have installed. Then refer to the chart and see where approximately you are going to be. Also, check a few other things there: how far the fuel bowls are located, power valve etc.

I am using a purple (7 in HG) spring in mine. After going through Q-jet, dissassembly of a Edel. (Carter) carb is a piece of cake. I had to buy the Edel. tune kit that comes with a bunch of rods, jets and springs.

Post your findings here, that'll definitely help us troubleshoot your problem.

Regards!
Denis
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 04-22-2005, 10:14 AM
wickster's Avatar
Member
 
Last photo:
Join Date: Mar 2004
Location: Calgary, Alberta, Canada
Posts: 139
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I have the tuning kit....and I am running Reference Point #8...can't remember which springs...I'll check tonight.

Also think I will take it apart and recheck the floats.
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 04-22-2005, 10:41 AM
Registered User
 
Last wiki edit: Mopar tapered axle rear brake conversion
Last journal entry: What I'm doing now...
Last photo:
Join Date: Jan 2002
Posts: 4,267
Wiki Edits: 49

Thanks: 0
Thanked 4 Times in 4 Posts
I suspect all you need to do is change the metering rod springs. The springs work on vacuum and if they are too strong for your engine vacuum level at idle they will not compress and you will wind up with a rich condition.
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 04-22-2005, 01:28 PM
killerformula's Avatar
Hotrodders.com Moderator
 
Last wiki edit: Carburetor
Last journal entry: Clean up
Last photo:
Join Date: Oct 2003
Location: Northeast
Age: 34
Posts: 3,485
Wiki Edits: 3

Thanks: 13
Thanked 27 Times in 18 Posts
we just installed that cam in a 327 10:1 motor. HE had the 7 inch springs on his too. But if you think about going from a stock cam with about 20 inches at idle to the 268 which has about 12, it make sense that you'd have to step down your springs a little bit too, because with that little vacuum to start with you're going to lose a lot in a hurry even with just a touch of the trottle. You don't want to have them bumping in too early, my guess is a 7 inch spring will be too much. I would use a 3 or 4.

K
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 04-22-2005, 05:17 PM
wickster's Avatar
Member
 
Last photo:
Join Date: Mar 2004
Location: Calgary, Alberta, Canada
Posts: 139
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
OK...found my setup sheet. Here is what I am running right now.....

Calibration Point #8
1455 Rod, 1426 Jet (6% Lean in Cruise)
1425 Secondary Jet (4% Lean)
Pink Spring (7")

O yeah...and we are at 3750 ft elevation.
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 04-22-2005, 06:37 PM
Member
 
Last photo:
Join Date: Mar 2003
Location: Bakersfield, CA
Posts: 397
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I would try leaning it out a little bit more - use rod 1426, position 7. Which position is your pump drive link?
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 04-22-2005, 07:05 PM
cboy's Avatar
Member
 

Last journal entry: Finished
Last photo:
Join Date: Jan 2004
Location: Atwater, CA
Age: 69
Posts: 3,915
Wiki Edits: 0

Thanks: 0
Thanked 2 Times in 2 Posts
Just had another thought. Have you checked your choke plate to make sure it sits at the fully open position at idle?

I'm still very hesitant about the wrong spring theory. It's easy enough to check (by swapping out the spring) but my guess is you will just mess up your throttle response - which you indicated is fine at present.

Darom's suggestion of the position 7 rod/jet is worth a try. Even 12 if 7 doesn't do it.
__________________
Always learning...and sharing what I've learned. The Scratch-Built Hot Rod.
Reply With Quote Quick reply to this message
  #12 (permalink)  
Old 04-22-2005, 11:30 PM
wickster's Avatar
Member
 
Last photo:
Join Date: Mar 2004
Location: Calgary, Alberta, Canada
Posts: 139
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Tried the Yellow spring (4")....NO GOOD. Drives fine...but when cruising at about 2800 and I punch it....kind of chugs a little then takes off....sounds to me like a lean condition. I hooked up the vac gage and when I punch it from idle (not in gear) I get a minimum of 5"....so I think the Pink (7") spring is right.

Pump drive link is on the top hole.

I will try position #7...tomorrow.

Thanks for the help so far.

I think I am getting there on the "drivability"..its the idle that is gassing me out of the garage....I am going to check the floats too tomorrow.

Last edited by wickster; 04-22-2005 at 11:36 PM.
Reply With Quote Quick reply to this message
  #13 (permalink)  
Old 04-23-2005, 07:18 AM
Steve karch's Avatar
Member
 
Last photo:
Join Date: Feb 2002
Location: Regina, Saskatchewan
Age: 55
Posts: 414
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
The step up spring wont effect idle as far as I know. They only come into effect when running off the idle circut. What I suggest is to hook up your vacuum advance to the manifold port (full vacuum at idle). This will bring your base idle up (as it will advance your timing) then back off on the base idle screw. Then, adjust your mixture screws for best idle vacuum. This will bring the throttle plates back onto the idle circut. I think, from what you describe, that you have uncovered the idle slot and are idling on the main circut. My 406 idle at aprox 13" vacuum and when i was running an Edelbrock (now have a Holley 750 hp dp) it would do the same as your engine at idle with either no vacuum advance or with the vacuum advance hooked to port. This basic tune up principal applies to either Holley or Edelbrock when running larger cams.

Steve
Reply With Quote Quick reply to this message
  #14 (permalink)  
Old 04-23-2005, 11:07 AM
Member
 
Last photo:
Join Date: Mar 2003
Location: Bakersfield, CA
Posts: 397
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
wickster,
your pump drive link is hooked up to the top hole? This is the setting which needs to be done for 750 carbs. Yours should be in the middle hole.

Here is a paragraph from the rebuilt manual I have:
"Back out idle speed screw to allow primary throttle valves to seat in bores. (Models 1405-1406-100) Install pump connector rod in the second hole from top of pump arm. Bend pump rod to obtain 17/32" (1,35cm) from top of pump shaft to bowl top."
Reply With Quote Quick reply to this message
  #15 (permalink)  
Old 04-23-2005, 12:25 PM
cboy's Avatar
Member
 

Last journal entry: Finished
Last photo:
Join Date: Jan 2004
Location: Atwater, CA
Age: 69
Posts: 3,915
Wiki Edits: 0

Thanks: 0
Thanked 2 Times in 2 Posts
Quote:
Originally Posted by Steve karch
I think, from what you describe, that you have uncovered the idle slot and are idling on the main circut.
I don't understand this section of your post. Could you explain a little more what you mean by the idle slot and how it can become "uncovered".

Thanks,
Dewey
__________________
Always learning...and sharing what I've learned. The Scratch-Built Hot Rod.
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


Similar Threads
Thread Thread Starter Forum Replies Last Post
5.565 or 5.7 rods? JohnyR17 Engine 9 10-09-2010 07:17 PM
Vacuum advance western star Engine 14 11-30-2009 10:28 PM
How metering rods work in Rochester Dualjet ? Olds 69 Engine 1 02-18-2005 02:56 PM
running super rich at idle??? ocbaud Engine 4 11-21-2004 02:21 PM
edelbrock carb. still too rich! TVR383 Engine 9 09-03-2003 02:27 PM


All times are GMT -6. The time now is 02:48 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.