Secondaries on a Edelbrock 650 Thunder - 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 06-20-2006, 07:36 AM
rac43's Avatar
Registered User
 
Last photo:
Join Date: Jun 2006
Location: Dallas Texas
Posts: 73
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Secondaries on a Edelbrock 650 Thunder

Need some advise. I just put a new Edelbrock 650 Thunder with vacuum operated secondaries on my 350 T-Bucket. Have a HEI ignition so no vacuum hooked to the carb and all vacuum inlets plugged. Now, my question. How wide should the secondary butterflies open? Under WOT and my looking down the throat, the primaries go wide open and the secondaries only open about 1/8th inch. Is this normal? It runs like a raped ape but need to get the best out of this 650. Thanks lots

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 06-20-2006, 07:45 AM
DoubleVision's Avatar
Not Considered a Senior Member
 
Last photo:
Join Date: Oct 2002
Location: Heart Of Dixie
Age: 40
Posts: 10,652
Wiki Edits: 0

Thanks: 15
Thanked 58 Times in 55 Posts
Your lucky they only open that far, Vac Sec carbs usually don`t open any or much when not under load.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 06-20-2006, 07:58 AM
Registered User
 
Last photo:
Join Date: Nov 2004
Location: Cali
Posts: 994
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Edelbrock describes the secondary operation like this:

A mechanical secondary air velocity valve in Performer Series carbs senses air-flow according to demand and automatically regulates a smooth transition from part throttle to wide-open throttle.

These carbs have mechanical secondary throttles that should open wide when you rotate the linkage all the way.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 06-20-2006, 08:07 AM
spinn's Avatar
Head like a Deathstar
 

Last journal entry: This makes a huge difference
Last photo:
Join Date: Oct 2004
Location: midwest
Posts: 2,287
Wiki Edits: 0

Thanks: 4
Thanked 70 Times in 68 Posts
i agree with double.. isnt it a vac secondary ?

*edit* on a holley
vac sec wont open just revving the engine in neutral. there has to be a load. the secondary idle enrichment comes from the amount of transfer slot showing in the secondaries.

on a stockish engine i use boxes. the slot is as long as is wide... or .020 whatever it sez.

on a mild or hot build i like a box and a half.

Last edited by spinn; 06-20-2006 at 09:12 AM. Reason: holley example explaination
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 06-20-2006, 08:43 AM
Registered User
 
Last photo:
Join Date: Nov 2004
Location: Cali
Posts: 994
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
The Holley vacuum secondary carbs have secondary butterflies that are operated by the vacuum developed in the primary venturis, the more vacuum in the venturi the farther they open. If you rotate the throttle mechanism completely, only the primary butterflies will open until the vacuum is sufficient.

The Edelbrock carbs have mechanically operated secondary butterflies, when you rotate the throttle mechanism fully, all four butterflies will open. The amount of air drawn through the secondaries is controlled by an air valve above the secondary butterflies. On the Performer series carbs the air valve has a fixed counterweight and the opening rate is not easily adjustable. On the Thunder series carbs the air valve is spring controlled and is easily adjustable.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 06-20-2006, 09:10 AM
spinn's Avatar
Head like a Deathstar
 

Last journal entry: This makes a huge difference
Last photo:
Join Date: Oct 2004
Location: midwest
Posts: 2,287
Wiki Edits: 0

Thanks: 4
Thanked 70 Times in 68 Posts
i guess they are not vacuum operated. thanks for the correction.

is this the one with spring rod down the center, and the doors open 80% ? i thought that was vacuum controlled.. oh well sorry for the confusion.
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 06-20-2006, 04:01 PM
rac43's Avatar
Registered User
 
Last photo:
Join Date: Jun 2006
Location: Dallas Texas
Posts: 73
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I have Thunder Eldelbrock, Not a Performer, Not a Holley

Quote:
Originally Posted by onovakind67
Edelbrock describes the secondary operation like this:

A mechanical secondary air velocity valve in Performer Series carbs senses air-flow according to demand and automatically regulates a smooth transition from part throttle to wide-open throttle.

These carbs have mechanical secondary throttles that should open wide when you rotate the linkage all the way.
I guess you all are trying to answer my question but I don't have a Holley, nor do I a have a Performer. I have a Elderbrock Square Bore Thunder carb. The secondaries DO NOT open more than 1/8th inch when the throttle is wide open. I thought someone here with experiance on a Thunder carb could offer me an answer. From the answers above, I now know what a Holley and a Performer card do. Anybody know anything about a Thunder Carb?
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 06-20-2006, 04:38 PM
Registered User
 
Last photo:
Join Date: Jan 2006
Location: NC
Posts: 201
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
ONOVAKIND. did answer your question your thunder edelbrock is easily adjustable.look on edelbrock web site. Wormy.
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 06-20-2006, 04:43 PM
spinn's Avatar
Head like a Deathstar
 

Last journal entry: This makes a huge difference
Last photo:
Join Date: Oct 2004
Location: midwest
Posts: 2,287
Wiki Edits: 0

Thanks: 4
Thanked 70 Times in 68 Posts
hold that thought

right on , that will explain it
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 06-20-2006, 04:51 PM
Registered User
 
Last photo:
Join Date: Nov 2004
Location: Cali
Posts: 994
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by rac43
I guess you all are trying to answer my question but I don't have a Holley, nor do I a have a Performer. I have a Elderbrock Square Bore Thunder carb. The secondaries DO NOT open more than 1/8th inch when the throttle is wide open. I thought someone here with experiance on a Thunder carb could offer me an answer. From the answers above, I now know what a Holley and a Performer card do. Anybody know anything about a Thunder Carb?
The Performer and Thunder series carbs share a lot of features, including mechanical secondary butterflies. The Thunder series isn't a new concept, they're a copy of the Carter AVS carbs that came on the 60's Mopars. I had one on my 68 Roadrunner that I bought new in 1968 after returning from Vietnam. You can see the features here:

http://www.edelbrock.com/automotive/..._features.html

If you read closely you will see the statement that I copied for my earlier reply. If your secondaries don't open fully when you rotate the throttle linkage to its limit, you should investigate the linkage for a problem.
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 06-20-2006, 05:31 PM
woodz428's Avatar
Troll Hunter
 
Last photo:
Join Date: Sep 2002
Location: Philo,Il
Posts: 2,702
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I'm wondering if you are confusing the air valve butterflies that are above the secondary plate with the secondary plate. You shouldn't be able to see the secondaries unless the air valve is opened. If you are seeing the secondary air valve butterflies only partially open, that is normal. Much like a Holley, it won't open fully unless under load. If you manually hold the air valve open so you can see the secondaries, you can open the throttle fully to see if they are operating correctly(engine off,of course). It is highly unlikely that the secondaries are only opening the little amount you are seeing, it would have been caught at the factory. I suspect you are perceiving the air valve as the secondaries.
Reply With Quote Quick reply to this message
  #12 (permalink)  
Old 06-20-2006, 06:12 PM
rac43's Avatar
Registered User
 
Last photo:
Join Date: Jun 2006
Location: Dallas Texas
Posts: 73
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Got is fixed! The linkage for the secondaries on the side of the carb had a tiny screw wedged between the linkage and the carb that were keeping the secondaries from opening all the way. A small black screw, no telling where it came from but now the secondaries open all the way under full open throttle. Thanks to all that tried to help with this. Problem solved!
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
Holley 650 / Edelbrock performer combo Andy in SD Engine 4 11-07-2005 09:25 AM
edelbrock thunder carb 79transam Engine 5 11-21-2003 09:34 AM
Edelbrock Thunder Series carb kaddylowrider Engine 1 11-06-2003 02:09 AM
Edelbrock 1904 secondaries question rakundig Engine 3 10-29-2003 07:56 PM
Edelbrock Qudarjet secondaries 56wagon Engine 7 05-17-2002 04:46 AM


All times are GMT -6. The time now is 01:04 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.