Page 1 of 3 123 LastLast
Results 1 to 15 of 37
  1. #1
    casual poster
    Join Date
    Feb 2012
    Location
    Australia
    Posts
    349

    Default Tips setting up a Holley 670cfm Street Avenger Carb

    Hi Everyone

    Acquired a pretty much brand new Holley Street Avenger 670cfm carb its had very little use and its condition shows. Im planning on fitting it to my 308 about to bolt it all up but thought I would check the transition slot on the butterflies. The carb I originally pulled off my motor was a 750cfm and the transition slot is roughly about the same as the 670cfm carb...... When I google or youtube setting up carbs it advises to only just see the line so basically it makes the line an even square this def. is not the case. Also how do you adjust the transition slot?

    See pics. How should I set it up. It was running on a Chrysler 318 5.2 litre he had it dyno tuned on his car they changed the vacuum secondary springs I have 2 spares a yellow and a black spring. They changed the power valve to a 4.5 which suits me I think as my vacuum is around 10hg. They did go up a couple of jet sizes.

    IMG_0036.JPG

    Also it has electric choke my old carby had no choke whatsoever. I need to hook up a wire from the choke to 12V power when ignition is on whats the easiest wire to grab to do this. I have read somewhere igntion coil or dizzy is no good as it can hover around 7-9 volts.

    Any other tips appreciated im going to have the air bleed screw turned out 1.5 turns each side. I also have the blue pump cam which I have read is generally the most accepted for performance applications once the carb is tuned right its screwed into position number 2.
    Last edited by bfhoon; 31-03-2018 at 12:15 PM. Reason: grammar

  2. #2
    Senior Member
    Join Date
    Jan 2017
    Location
    Nth Qld
    Posts
    691

    Default

    hi
    power source for choke , ignition ON RUN only fused .
    Choke coil should be 12v

    Some Holleys have secondary throttle stop screws . Can only be adjusted with carby off .

    Secondary opening depends on many things very individual to each car engine combo . Open as quick as possible without falling flat on its face

    Set accel pump cam to hole 1 if idle can be low eg 600---900. If high idle install in no2 hole

    Holley accelerator pumps/cams | Grumpys Performance Garage

    secondary spring kit
    accel pump cam kit
    accel pump nozzle kit

    What do u want to tune it for street[compromise ] ,, economy [max lean ] ,, drag [always rich ]

    try to have your primaries working at light throttle cruise 50--85 kph main jets
    Power valve whats your vacumm SET at 80kph / This is the start of power valve operation

  3. #3
    Senior Member
    Join Date
    Feb 2018
    Location
    Brisbane
    Posts
    489

    Default

    Way to much open in the transfer slot. Back off secondary throttle as per what you have mentioned.

  4. #4
    casual poster
    Join Date
    Feb 2012
    Location
    Australia
    Posts
    349

    Default

    So can I adjust the transfer slots on the primaries or not? Ive bolted it all up now I didnt want to get adventerous with playing around with the secondary adjustment. I can see now if I wish to adjust it I need to remove the carby. Ive got my idle set to about 950rpm using cam slot 2 still. It did foul up my plugs badly. Had a little play around and cleaned up my plugs. They now seem to be staying cleanish. Ive noticed I can nearly wind my idle air screws all the way in before it stall. Not all the way but nearly.

    Car def doesnt go as hard or pull as hard as the old 750 did ( not heaps concerned about that but may play around with different springs in the vacuum secondaries.

    One thing I did notice is after I accelerate and let my foot off the idle drops down slowly like its surging back up a bit. Would this just need accelerator pump adjustment

  5. #5
    Senior Member
    Join Date
    Feb 2018
    Location
    Brisbane
    Posts
    489

    Default

    You adjust your transfer slot ‘exposure’ by adjusting the idle speed screw. Your over run after acceleration may be because the secondaries are too far open (as per your picture). You have to get everything back to a base setting before making changes or you’ll be chasing this forever, with no real result.

  6. #6
    casual poster
    Join Date
    Feb 2012
    Location
    Australia
    Posts
    349

    Default

    Quote Originally Posted by Castiron355 View Post
    You adjust your transfer slot ‘exposure’ by adjusting the idle speed screw. Your over run after acceleration may be because the secondaries are too far open (as per your picture). You have to get everything back to a base setting before making changes or you’ll be chasing this forever, with no real result.
    I couldnt adjust the primaries down at all I was winding the idle screw and the slots didnt move I think because I have a green spring that sets them up to be open that far. I could wind the spring in however and increase it. Am I able to change the spring or back to standard ( im only assumign ths is the issue )

    Dont really want to pull it all down again and make a fuel mess might see if I can buy a small right angled flathead screwdriver for this task of closing up the secondaries which way to tuen assuming screwing out closes them

  7. #7
    Senior Member
    Join Date
    Feb 2018
    Location
    Brisbane
    Posts
    489

  8. #8
    Senior Member
    Join Date
    Jan 2017
    Location
    Nth Qld
    Posts
    691

    Default

    Hi
    Sounds like the primary mix screws are having trouble controlling the idle mixture .
    Set the secondary throttle blades back to standard via adj screw
    Once set std the mix screws function normal about 1 turn out ??

    Whats the actual problem when carb is set up as factory ??

    Whats the idle vacumm in D [auto] ??

  9. #9
    casual poster
    Join Date
    Feb 2012
    Location
    Australia
    Posts
    349

    Default

    Its a manual I acheive about 9-10hg vacuum. It still smells fuelly I took it for a good drive came back and let it sit idle for 5 minutes pulled the plugs out they dont look fouled or anything the earth strap is pretty clean and the base of the thread is even fairly clean im also running 6 heat range ngk.

  10. #10
    Senior Member
    Join Date
    Feb 2018
    Location
    Brisbane
    Posts
    489

    Default

    Wrong manifold. Secondaries too far open.

  11. #11
    casual poster
    Join Date
    Feb 2012
    Location
    Australia
    Posts
    349

    Default

    Quote Originally Posted by Castiron355 View Post
    Wrong manifold. Secondaries too far open.
    Ill try closing the secondaries if i can do it without removing im assuming wind screw down to close up the blades

    Sent from my SM-G900I using Tapatalk

  12. #12
    casual poster
    Join Date
    Feb 2012
    Location
    Australia
    Posts
    349

    Default

    Quote Originally Posted by bfhoon View Post
    Ill try closing the secondaries if i can do it without removing im assuming wind screw down to close up the blades

    Sent from my SM-G900I using Tapatalk
    Got to the screw just probably lucky its a hi rise manifold it was a pita though. I have turned it out however the vacuum actuator is just sitting above the screw so technically its done nothing the same thing happens when i adjust the idle curb screw i get to a point where the screw is in thin air so have no adjustment to bring the buitterflies closed more.

    Im not heaps concerned with the primaries now but I want to fix the secondaries. Any one got any ideas?

  13. #13
    Senior Member
    Join Date
    Feb 2018
    Location
    Brisbane
    Posts
    489

    Default

    Quote Originally Posted by bfhoon View Post
    Got to the screw just probably lucky its a hi rise manifold it was a pita though. I have turned it out however the vacuum actuator is just sitting above the screw so technically its done nothing the same thing happens when i adjust the idle curb screw i get to a point where the screw is in thin air so have no adjustment to bring the buitterflies closed more.

    Im not heaps concerned with the primaries now but I want to fix the secondaries. Any one got any ideas?
    Okay so you back the primary screw right out so it’s not touching anything as well as the secondary screw. Then wind them in till they just touch the stops and go 1/4 turn. Then run it and try mixtures etc.

  14. #14
    casual poster
    Join Date
    Feb 2012
    Location
    Australia
    Posts
    349

    Default

    Thats how it was set up when I first got it and I took the photo of the base plate showing the over exposed transfer slots. So I have no adjustment to bring them back in?? The only adjustment I have is to hit the stops and keep winding which just over exposes them even worse? Could the blue pump cam have something to do with this?

  15. #15
    Senior Member
    Join Date
    Feb 2018
    Location
    Brisbane
    Posts
    489

    Default

    Quote Originally Posted by bfhoon View Post
    Thats how it was set up when I first got it and I took the photo of the base plate showing the over exposed transfer slots. So I have no adjustment to bring them back in?? The only adjustment I have is to hit the stops and keep winding which just over exposes them even worse? Could the blue pump cam have something to do with this?
    Pump cam can’t affect throttle opening. I forgot you have a choke. The throttle position in the photo may be due to the fast idle adjustment for the choke. When the choke is on it will crack the throttle open a bit. Need to start engine and warm it up. If after it’s warm it may not idle. Then set your curb idle speed. In the PDF Link I sent above there is a good explanation on setting the choke.

Page 1 of 3 123 LastLast

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Holley 650 ultra street avenger
    By chriso2stroke in forum For Sale Items
    Replies: 0
    Last Post: 14-10-2015, 08:13 PM
  2. Replies: 2
    Last Post: 19-08-2012, 06:32 AM
  3. Help with holley 670cfm street avenger
    By EB 355 in forum Members Lounge
    Replies: 2
    Last Post: 05-09-2010, 09:35 AM
  4. F.S Holley 670cfm street avenger carb
    By tuff308 in forum For Sale Items
    Replies: 4
    Last Post: 22-08-2006, 08:54 AM
  5. F.s Holley 670cfm Street Avenger
    By tuff308 in forum For Sale Items
    Replies: 0
    Last Post: 17-05-2006, 10:58 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •