200-4R line pressure too high

Discussion in 'The "Juice Box"' started by ravensbud, Jun 13, 2019.

  1. ravensbud

    ravensbud Silver Level contributor

    Uuuugh!!! I did my research. I knew I couldn’t rebuild a 200-4R to hold 600hp myself. I spent ~5k very hard earned dollars to buy the best tranny I could get, using a CZ trans. Using one of the best builders in the country.

    Install went fine. I used the Bowtie Overdrives TV made EZ cable kit, using their spring as directed. Fired it up and idle line pressure was 115lbs. Shifts were way too high (>3100rpm off idle) and smashingly hard. This is classic long spring syndrome.

    I got 3 new TV springs, all of which were shorter (my builder’s “custom” spring, a stock CZ spring and another stock spring even a bit shorter) on advice of my builder and idle pressure dropped to 104 but this is still not drivable. Cable is absolutely adjusted properly. Car is not drivable. Shifts to 2nd at off idle at ~28 mph (way high rpm with 3.90 gears) and stack shifts after that with loud bangs.

    Anyone have advice? I’m afraid I’m gonna have to eat the cost of new tranny and go back to th400.
     
  2. 455monte

    455monte Well-Known Member

    How big is your boost valve?
    I put a .500 in mine and it pissed off the line pressure and made trans start in 2nd gear.
    Went back with the stock .4xx boost valve and it dropped line psi to an acceptable level
     
    techg8 and ravensbud like this.
  3. ravensbud

    ravensbud Silver Level contributor

    I’m not going to pretend to discuss this intelligently since I opted to pay big $ for an expert to build it, but build description says .531 forward boost valve. I’ll ask about this...thanks u so much for the tip.
     
  4. Skylard

    Skylard Well-Known Member

    i had a builder send me a $3500 trans, it poured fluid everywhere at high rpm. he sent me another one, the input shaft broke driving on the street.
    i bought a $1100. kit from CK performance and rebuilt it myself, i've been beating on the trans for 5 years now with out issue.
    JW convertor.
    I dont know if it would hold 600hp
    Cheers!
     
  5. TexasT

    TexasT Texas, where are you from

    What is the pressure at idle with the TV cable disconnected from the carb?
    If you put it in you should have the ability to swap in a smaller boost valve. That .500 or a .471 might get you down some to a more manageable pressure.
    Have you at least contacted the builder? The ones I have had contact with seemed like they wanted their products to work.
     
  6. ravensbud

    ravensbud Silver Level contributor

    I’ve got the disconnected idle pressure down to 105 with a stock CZ spring. It’s still shifts too hard for comfortable driving, but is better.

    The builder is making a good effort to help me get this right. Next step will be to shorten the tv spring just a touch and then check pressures.
     
  7. TexasT

    TexasT Texas, where are you from

    The boost valve controls boost pressure. And yours is the large one. If it is shifting hard I would say this builder knows how to set one up. Mine are "snappy" wth the .500 valve. That is where I would be making the mod. A shorter tv spring just moves that valve to a different position (could affect some stuff but with the idle pressure over 100psi I'd be looking to get that under 100 psi before moving to other "cures")
    Www.tvmadeez.com as some good diagrams on how the tv valve in the vb works.
     
    ravensbud likes this.

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