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Technical 1955 Chrysler SBC DYING. Transmission I think???

Discussion in 'The Hokey Ass Message Board' started by 1957heaven, Feb 10, 2019.

  1. 1957heaven
    Joined: Mar 10, 2016
    Posts: 6

    1957heaven
    Member
    from Colorado

    Ok. A little back ground.

    1955 Chrysler with Stock 350 small block Chevy motor. TH400 trans.

    Edlebrock 600cfm carb. HEI distributor.

    All new ignition system. All new fuel system. Pump (electric) filters etc.

    Starts first turn. Isles fine. Choke works as it should. Put it in gear it rolls under idle fine.

    As soon as there is a load: like backing over the 2” lip on my driveway. It dies.

    After it dies it becomes hard to start like it’s starving for fuel.

    I pull the line and it has great pressure at carb.

    I am stumped. The car drove just fine and all of the sudden no power or acceleration. It sounds great except under load.

    Ps. I did change the vacuum modulator today no difference. I didn’t think it would.

    Any help is appreciated.

    Shane
     
  2. David Gersic
    Joined: Feb 15, 2015
    Posts: 1,606

    David Gersic
    Member
    from DeKalb, IL

    You sure the fuel pump is good?

    Why do you think it’s the transmission?


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  3. Paul
    Joined: Aug 29, 2002
    Posts: 14,116

    Paul
    Editor

    Exhaust plugged?
     
  4. Atwater Mike
    Joined: May 31, 2002
    Posts: 8,933

    Atwater Mike
    ALLIANCE MEMBER

    Waitaminnit... Won't forge the lip of the driveway? Look under the hood. Someone probably slipped a SBC in there!

    All kidding aside...agree with Paul. Disconnect the exhaust at the headpipes, (loosen bolts at flanges, let pipes hang) Now try for 'power'.
     
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  5. s55mercury66
    Joined: Jul 6, 2009
    Posts: 2,793

    s55mercury66
    Member
    from SW Wyoming

    Accelerator pump working?
     
  6. 1957heaven
    Joined: Mar 10, 2016
    Posts: 6

    1957heaven
    Member
    from Colorado

    Well. They are straight pipes. Not very long but I can try it.
     
  7. 1957heaven
    Joined: Mar 10, 2016
    Posts: 6

    1957heaven
    Member
    from Colorado

    Two carbs. Actually 3. One on it now is brand new.
     
  8. 1957heaven
    Joined: Mar 10, 2016
    Posts: 6

    1957heaven
    Member
    from Colorado

    Because it idles and revs with no load so well sounds and acts great until it’s under load.
     
  9. David Gersic
    Joined: Feb 15, 2015
    Posts: 1,606

    David Gersic
    Member
    from DeKalb, IL

  10. VANDENPLAS
    Joined: Dec 14, 2009
    Posts: 1,391

    VANDENPLAS
    Member

    Sounds like a fuel issue.
    What is your fuel pump pressure?

    Filters not plugged?

    Tank clean?

    Hookup a vacuum gauge and see what the engine is doing.

    Could have a vacuum leak that only shows up under load ..... possibly .

    I don’t think it could be but your distributor,timing, engine timing etc is all set correctly?
     
  11. Hnstray
    Joined: Aug 23, 2009
    Posts: 9,961

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    The Chrysler is embarrassed to be powered by a lowly Chevy and is choking the engine to death to avoid being seen on the street. Jerk that mouse motor out of there and put in a proper Mopar powerplant and it will run and drive just fine.....
     
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  12. gene-koning
    Joined: Oct 28, 2016
    Posts: 946

    gene-koning
    Member

    Is it cold out there? Maybe the choke is opening too fast and causing a lean condition, or its not opening fast enough and its flooding the motor with gas. When you try to restart it, is the motor up to operating temp? Is the choke open, or closed? A half warm motor with cold temps causes real problems with chokes, the motor may need more choke, or it may not need any. Gene
     
  13. Oh, this one is easy. I've had this happen several times.....and it was the HEI module. 15 minute repair.
     
  14. Mr48chev
    Joined: Dec 28, 2007
    Posts: 24,016

    Mr48chev
    ALLIANCE MEMBER

    Well first, I don't think it is the transmission unless it is totally screwed up inside and locking up. That is real doubtful.
    Probably not the module but it could be the lead on the pickup coil having the wire broken and while it makes contact when the engine idles as soon as the vacuum advance starts moving the broken wire looses contact but makes contact after it shuts off and sits for a while. I had that proven to me a few years ago on one that did somewhat the same thing.
    Choke opening too fast in Colorado in the first week of frigging Feburary and letting the engine run lean an die. Quite plausible. Engine won't start after it stalls because the choke is now hanging open and won't give a rich enough mixture? Yup, every one of us who have driven a car with the choke blocked open year round have fought that battle..
    Chrysler rejecting the Chebbie engine? Well sticking a Chevy small block in something as cool as a 55 Chrysler rater than a Mopar V8 should call for being tied between a couple of trees and beat with a rust tire chain but it probably didn't reject it.
    Wrong gas cap that is creating a vacuum in the tank after it runs a bit and not letting fuel to the carb after it runs a bit? If the tank is close to full the time before it dies is real quick as compared to if it just has a couple of gallons in it. I walked 3/4 of a mile to a gas station over that one once when I had just put a brand new "vented" cap on the car.
    If it ran good before this episode, think back to any change you made or anything you did including stopping at an old gas station with old tanks that might have water in the gas. I don't do quaint old gas stations no matter how cute they are unless I am in some spot where there is absolutely no other choice.
     
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  15. 1957heaven
    Joined: Mar 10, 2016
    Posts: 6

    1957heaven
    Member
    from Colorado

    All good points. I agree putting the SBC in was a mistake, not made by me, but a mistake nonetheless.

    I bought this car for my son it was a great starter project, from a friend. I knew only what history he knew which want much since he took it as part of another trade deal.
    The SBC and GM trans were in it when we got it. Original paint, interior, etc. nice looking mild custom. we dropped new front end in new disk brakes kit front, new GM power steering, etc. All things made it better.

    Then when we try to take the new Maiden voyage, it backfired, spit sputtered, noises and cuss words.
    The motor in it threw a bearing, cam bearing and had several flat lobes.

    Fast-forward. I put a known SBC in its place, from a truck I own and once was a daily driver, I drove it to the spot where we swapped it out.

    Now the move thread is the problem.......sorry for no more details but this is what I know. I have tried, three distributors, there carburetors, two fuel pumps, in varying combinations????

    Also there may be a free Craigslist curb alert soon for a demon possessed project....thanks again for any insight.
     
  16. Heavy Old Steel
    Joined: Feb 1, 2019
    Posts: 16

    Heavy Old Steel
    Member
    from Virginia

    Try disconnecting the vacuum advance and plugging the hose and setting as much initial advance as it will take and still idle and rev, then put a load on it as a test.
     
  17. David Gersic
    Joined: Feb 15, 2015
    Posts: 1,606

    David Gersic
    Member
    from DeKalb, IL

    Is this Christine’s older sister?

    Ok, so you took out a running driving perfectly good engine from your truck, put it in this car, and now it won’t run?

    I’m still thinking fuel pump. How about a cheap test with an SBC mechanical pump? They’re like $15 at AutoZone. Or gravity feed the carb from a gas can.



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  18. 52HardTop
    Joined: Jun 21, 2007
    Posts: 728

    52HardTop
    Member

    I'm thinking ignition/ electrical issue?
     
  19. sunbeam
    Joined: Oct 22, 2010
    Posts: 3,723

    sunbeam
    Member

    Trans plant rejection.
     
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  20. VANDENPLAS
    Joined: Dec 14, 2009
    Posts: 1,391

    VANDENPLAS
    Member

    Stupid thing to look at but.......


    I had a sbc that I crossed two wires, idled perfect, accelerated great when in park, under load would pop and fart out of the carb and die.
    It would restart,
    Idle, accelerate perfect no load.
    Under load
    Nothing!

    Just a thought.
     
  21. manyolcars
    Joined: Mar 30, 2001
    Posts: 7,522

    manyolcars

    Its a vacuum leak
     
    bobss396 likes this.

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