Can not tune 1970 Buick 455 GS

Discussion in 'Classic Buicks' started by Tom Hoenig, Aug 18, 2021.

  1. bostoncat68

    bostoncat68 Platinum Level Contributor

    Hey Tom did you talk to the guys at Paintworks Unlimited in Dover?
     
  2. Tom Hoenig

    Tom Hoenig Active Member

    Not yet, I am trying one more thing. I am personally going to rebuild the carb and see how it runs. I will call them anyway, because I think the motor needs to be done.
     
  3. Tom Hoenig

    Tom Hoenig Active Member

    Ok to all who have been trying to help. THANK YOU!!! Here is the latest report. I rebuilt the carb myself rather than having the professional mechanics out there do it. THE HESITATION IS NOW GONE!!!! I found, 1 of the short screws in the air horn missing. One of the pair that sits under the choke plate. No spring in the fuel filter in front at all. Also another rookie mistake is the float spring was set in the left hole of the bracket and not swinging from the shelf as shown in a 100 videos. (I believe this caused the plunger to get hung up but maybe I am wrong). Also found that the primary jets were not smooth up and down and the bore should have been honed for smooth operation. All in all I though after 2 expert mechanics rebuilt this carb they should be ashamed of a dabbler like me finding such obvious mistakes.

    So at the end of the day the car is now tolerable to drive. It still has the loading up (problem) in gear, lights on, or any other load on the motor at idle. What I also found was the carb I rebuilt to remove the hesitation had 75 jets and 44B rods which are very rich based on this not being a stage one 455. My thinking is still an internal vacuum leak and that is why It like this carburetor and runs better. I still have low vacuum. My thought was to pull the intake manifold and see for myself if there is something wrong. i.e. Not sitting flat or a crack somewhere. I was going to put an aluminum edelbrock on there but I have read this is not a good alternative. Thoughts?
     
    12lives and PGSS like this.
  4. Brett Slater

    Brett Slater Super Moderator Staff Member

    Who had their hands in that carb?
     
  5. Tom Hoenig

    Tom Hoenig Active Member

    Complete Auto in Allenstown NH and Ayers Auto in Raymond NH. Both claim to work on Performance and classic cars. Both of them are bolt on mechanic’s at best. IMO
     
  6. Reidk

    Reidk Well-Known Member

    When you swapped in your hei distributor did you run a new 10 gauge power wire all the way back to the fuse panel? Also, you could have too tight of a torque converter for that cam. A looser converter won't work against your motor so hard while breaking at a stop sign.
     

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