Page 8 of 9 FirstFirst ... 56789 LastLast
Results 106 to 120 of 121
  1. #106
    Senior Member BasicQ's Avatar
    Join Date
    Apr 2020
    Location
    Geelong
    Posts
    572

    Default

    If you have one similar to this with a pressure scale then yes. Take you coil lead off and give it about 20 sec cranking. Also possible to connect to fuel pump inlet and check suction. Look for around 5.5 psi outlet and 10 inHg inlet.

    [img]https://i.ibb.co/Thz8bkG/07-DE11-E8-28-AD-4-E14-8-AD1-7412-A51-F04-E8.jpg[/img]


    Sent from my iPad using Tapatalk

  2. #107
    casual poster
    Join Date
    Jun 2015
    Location
    South Africa
    Posts
    297

    Default

    Hey guys, just an update

    I found a possible issue on the intake. When the motor was apart for overhaul, I decided it was a good time to relocate the carb return spring to the rear of the intake. Mine originally was located at the front of the intake. During the drilling and tapping I made a hole through the intake. When I assembled the motor I used thread tape on the bolt into the hole to seal.
    I removed the bolt and noticed the area slightly oil, perhaps a small vacuum leak here. I put thread tape again and the erratic idle seemed to have gone away.
    I have now used RTV on the bolt threads to try make a better seal after removing the thread tape.
    I still have both carbs and will test over the weekend to see whether there is a marked improvement.

    Any better suggestions for a better seal on the bolt hole?

  3. #108
    Senior Member
    Join Date
    Nov 2018
    Location
    Sydney
    Posts
    731

    Default

    Two points.

    Don't use RTV where petrol or fumes come in contact with it. It softens up. If you are sealing a threaded hole in the induction system, use Loctite 567 Pipe Sealant.

    Many GM cars used a throttle return spring mounted on the lower part of the carb throttle arm, with the spring anchored behind the carb. Bad design. Both the throttle & spring pull back on the t/shaft. A 'double' pull if want to look at it that way. So shaft & bore wears, QJs have a reputation for it.

    Chrysler got it right. Spring hooks to the upper part of the linkage & spring is anchored in front of the carb. This arrangement 'equalises' the pull on the shaft. Having worked on Chrysler cars & carbs since the 1970s, I have never seen or heard of an AFB, AVS or TQ wearing out the shaft.

  4. #109
    been here .......too long Smitty2's Avatar
    Join Date
    Mar 2007
    Location
    bayside Melbourne
    Posts
    9,995

    Default

    Quote Originally Posted by GtoGeoff View Post

    Many GM cars used a throttle return spring mounted on the lower part of the carb throttle arm, with the spring anchored behind the carb. Bad design. Both the throttle & spring pull back on the t/shaft. A 'double' pull if want to look at it that way. So shaft & bore wears, QJs have a reputation for it.

    ..................
    thats not a problem where a cable throttle is used (GMH used it on all Commodores for example)
    but
    it is where a rod type linkage is used (usually pivoting off the fire wall)

    GM had a worldwide corporate policy that what ever design of carby linkage was used under NO circumstances
    could the design allow the linkage and/or carb to go 'over-centre' and jam at WOT.

    Used to drive me nuts on my HT GTS 350 when I was adjusting the Quaddie to make sure I got
    the primary throttles to open 100 %. Linkage design won't allow it....

    but on the race car (VK Commodore) no problem ... cable at bottom pulls against spring tension

    20200204_065842_s.jpg
    __________________________________
    ONE OF THE Aussie V8 MODERATOR/ADMIN TEAM

    Never late in an AussieV8!
    Club circuit racing...the best fun you can have with your pants on

  5. #110
    casual poster
    Join Date
    Jun 2015
    Location
    South Africa
    Posts
    297

    Default

    Quote Originally Posted by GtoGeoff View Post
    Two points.

    Don't use RTV where petrol or fumes come in contact with it. It softens up. If you are sealing a threaded hole in the induction system, use Loctite 567 Pipe Sealant.

    Many GM cars used a throttle return spring mounted on the lower part of the carb throttle arm, with the spring anchored behind the carb. Bad design. Both the throttle & spring pull back on the t/shaft. A 'double' pull if want to look at it that way. So shaft & bore wears, QJs have a reputation for it.

    Chrysler got it right. Spring hooks to the upper part of the linkage & spring is anchored in front of the carb. This arrangement 'equalises' the pull on the shaft. Having worked on Chrysler cars & carbs since the 1970s, I have never seen or heard of an AFB, AVS or TQ wearing out the shaft.
    It would then seem that I was given bad advice to relocate the return spring to the rear of the carb. This just makes me angry as I have now created a problem which I now need to fix, i..e the hole in the intake.
    My linkages are all rods not cable.

  6. #111
    Senior Member
    Join Date
    Nov 2018
    Location
    Sydney
    Posts
    731

    Default

    Smitty,

    It is a problem whether a cable or rod linkage is used. It as all about the force pulling or pushing on the shaft, whether it is cable or rod linkage. The only difference might be between the two systems is the weight and/or friction which will effect the spring strength reqd to return the throttle to idle.

    Ponntiacs used a short, straight, cable about 20" long that wore out the shaft/housing in QJs. Didn't happen with AFBs because they had about 3 times the area to spread the load.

    Chevs generally used a linkage, but pretty sure they started using cables in the late 60s.

  7. #112
    Senior Member
    Join Date
    Nov 2018
    Location
    Sydney
    Posts
    731

    Default

    Smitty,

    I looked at the pic of your cable. Same problem. Cable & spring pull in same direction putting extra force on the t/shaft. You could create a balanced force by hooking the spring on the bottom the t/arm [ where the cable attaches ] & anchoring the spring[s] behind the carb.

    Also, are you aware how poorly those air foam filters flow? It looks like a foam type filter. D. Vizard tested these types against a K & N. All three were very close in size. New, KN flowed 440, Foam types 378 & 351 cfm. After subjecting the filters to dust, KN still flowed 97.5% of original. Foam filters 50.8, 25.9%.

  8. #113
    Not the Kingswood! hq308's Avatar
    Join Date
    May 2010
    Location
    The Riff
    Posts
    2,442

    Default

    I agree with Geoff () on the return spring placement. Having them on the same side of the carb will eventually wear the throttle bushes on that side.

  9. #114
    casual poster
    Join Date
    Jun 2015
    Location
    South Africa
    Posts
    297

    Default

    My Chevy truck which in essence is a Holden, rebadged when GM brought them to South Africa has the rods and not cable. My year of manufacture is 1972.

    Will there be any adverse effects on the throttle shaft should I choose to locate 2 return springs one at the front and another from the rear?

    I will be getting my shaft rebushed in time as there is a some play which at times prevents the primary flaps from returning all the way to idle.

  10. #115
    Senior Member
    Join Date
    Nov 2018
    Location
    Sydney
    Posts
    731

    Default

    The idea is to try 'balance' the force or load on the t/shaft to minimise wear. So there would be some adverse affect if there is a spring pulling in the same direction as the linkage/cable. It might take many kms before it becomes an issue....& somebody else's problem....

  11. #116
    casual poster
    Join Date
    Jun 2015
    Location
    South Africa
    Posts
    297

    Default

    Quote Originally Posted by GtoGeoff View Post
    The idea is to try 'balance' the force or load on the t/shaft to minimise wear. So there would be some adverse affect if there is a spring pulling in the same direction as the linkage/cable. It might take many kms before it becomes an issue....& somebody else's problem....
    So best to have the return at the front only, got it.

  12. #117
    casual poster STOKESY77's Avatar
    Join Date
    May 2014
    Location
    Darwin
    Posts
    92

    Default

    Screenshot_2021-04-07-10-26-03-61[1].jpg

    On my setup throttle cable attaches from rear and return spring attaches from the front using billet alloy throttle cable bracket.

  13. #118
    Senior Member
    Join Date
    Nov 2018
    Location
    Sydney
    Posts
    731

    Default

    Excellent set up!

  14. #119
    been here .......too long Smitty2's Avatar
    Join Date
    Mar 2007
    Location
    bayside Melbourne
    Posts
    9,995

    Default

    Quote Originally Posted by hq308 View Post
    I agree with Geoff () on the return spring placement. Having them on the same side of the carb will eventually wear the throttle bushes on that side.
    will have a bit of a head scratch... as my category rules I race under require TWIN return springs
    (for vehicles not running EFI or PFI systems) easily visible for the scrutineers to view and test
    ... hence the placement of where they currently are

    made worse by the fact I dont race with the Lynx triangle filter (for garage only) but
    a much larger (14") K&N 2" filter with CAI which covers most of the throttle cable connection
    hmmmm... will see
    __________________________________
    ONE OF THE Aussie V8 MODERATOR/ADMIN TEAM

    Never late in an AussieV8!
    Club circuit racing...the best fun you can have with your pants on

  15. #120
    Not the Kingswood! hq308's Avatar
    Join Date
    May 2010
    Location
    The Riff
    Posts
    2,442

    Default

    Quote Originally Posted by Smitty2 View Post
    will have a bit of a head scratch... as my category rules I race under require TWIN return springs
    (for vehicles not running EFI or PFI systems) easily visible for the scrutineers to view and test
    ... hence the placement of where they currently are

    made worse by the fact I dont race with the Lynx triangle filter (for garage only) but
    a much larger (14") K&N 2" filter with CAI which covers most of the throttle cable connection
    hmmmm... will see
    In an occasionally used street car or race car I think it will probably take a while for it to be an issue. If you did want to sort it out you could run the cable from the backside of the carb and leave the springs where they are.

    How do they see the springs when you have the cold air tray on?

Thread Information

Users Browsing this Thread

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

Similar Threads

  1. Quadrajet 7029282
    By kavesh in forum Holden V8's
    Replies: 0
    Last Post: 30-05-2019, 05:03 AM
  2. Part number
    By Wheelofortune in forum Members Lounge
    Replies: 1
    Last Post: 05-10-2018, 11:43 PM
  3. Part number
    By Wheelofortune in forum Job Board
    Replies: 0
    Last Post: 05-10-2018, 08:38 PM
  4. Hg ht Hk part number
    By coupehq in forum Holden V8's
    Replies: 1
    Last Post: 12-03-2012, 09:35 AM
  5. Part Number
    By Kadett-Rekord in forum Holden V8's
    Replies: 6
    Last Post: 30-12-2008, 07:42 PM

Posting Permissions

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