Which Valve Springs with Purple Shaft P4102661?

Big Block A body Tech

  1. Red_Duster

    Red_Duster Well-Known Member

    Messages:
    271
    Likes Received:
    163
    Joined:
    Apr 17, 2019
    Location:
    California
    Local Time:
    1:29 AM
    Good morning all,
    I cant seem to find the information on spring rates anywhere for this cam. Its the older Mopar Purple Shaft grind. Working with a head manufacturer and exploring some options, but neither they nor I can seem to find the required spring information. I've checked Summit, Jegs and Mancini.

    Anyone running this cam, and what springs are you using?
    Thank you.
     
  2. roccodart440

    roccodart440 Well-Known Member

    Messages:
    5,527
    Likes Received:
    4548
    Joined:
    Apr 19, 2010
    Local Time:
    4:29 AM
    IIRC it used to have this info in the mopar performance catalogs. See if you can get your hands on one of them.
     
  3. rumblefish360

    rumblefish360 So close, yet so far away FABO Gold Member

    Messages:
    38,129
    Likes Received:
    9794
    Joined:
    Jun 21, 2005
    Location:
    New York, on a Island
    Local Time:
    4:29 AM
    Is that the 280/.474 cam?
    In there books they have a list of there springs. If you can those particular springs at least MP lists the general specs. From there you can cross reference them to another spring.
     
  4. Red_Duster

    Red_Duster Well-Known Member

    Messages:
    271
    Likes Received:
    163
    Joined:
    Apr 17, 2019
    Location:
    California
    Local Time:
    1:29 AM
    296/.557
    Ill see if I can track down a book. Not having too much luck.
     
  5. Daves69

    Daves69 FABO Gold Member FABO Gold Member

    Messages:
    4,941
    Likes Received:
    3065
    Joined:
    Feb 20, 2011
    Location:
    WestOfChi
    Local Time:
    3:29 AM
    …….
    upload_2019-11-22_12-44-10.png
     
    • Thanks! Thanks! x 1
    • Red_Duster

      Red_Duster Well-Known Member

      Messages:
      271
      Likes Received:
      163
      Joined:
      Apr 17, 2019
      Location:
      California
      Local Time:
      1:29 AM
      Thanks Dave, that awesome. I can cross-reference that and hopefully find some options.

      Now that prompts another question... I'm just learning valve train stuff, so bare with me, but why different lashes when the duration is the same. Didn't have the cam card, so I set both at .028
       
      • Like Like x 1
      • Dartwizer

        Dartwizer Member FABO Gold Member

        Messages:
        228
        Likes Received:
        22
        Joined:
        Jun 1, 2008
        Location:
        Mississippi
        Local Time:
        3:29 AM
        Found this 20191122_125031.jpg
         
      • roccodart440

        roccodart440 Well-Known Member

        Messages:
        5,527
        Likes Received:
        4548
        Joined:
        Apr 19, 2010
        Local Time:
        4:29 AM
        Is it a .028 int / .032 exh cam spec?
         
      • Red_Duster

        Red_Duster Well-Known Member

        Messages:
        271
        Likes Received:
        163
        Joined:
        Apr 17, 2019
        Location:
        California
        Local Time:
        1:29 AM
        Based on what Daves69 posted, it looks that way. I assumed that if the lift and duration int/exh were the the same, the lash would be the same. I'm sure the Mopar engineers knew what they were doing, Im really more just curious as I try and understand how all the valve-train works in relation to each other.
         
      • roccodart440

        roccodart440 Well-Known Member

        Messages:
        5,527
        Likes Received:
        4548
        Joined:
        Apr 19, 2010
        Local Time:
        4:29 AM
        I always ran mine .004 tighter than stock cold spec.

        .028 / .032 is noisy and ridiculous lash.
         
        • Agree Agree x 2
        • 383Duster

          383Duster Well-Known Member

          Messages:
          1,839
          Likes Received:
          480
          Joined:
          Jan 11, 2009
          Location:
          Dallas, TX.
          Local Time:
          3:29 AM
          Bigger lash spec on the exhaust valve was probably so it could spend more time on the seat for heat transfer
           
          • Agree Agree x 1
          • rumblefish360

            rumblefish360 So close, yet so far away FABO Gold Member

            Messages:
            38,129
            Likes Received:
            9794
            Joined:
            Jun 21, 2005
            Location:
            New York, on a Island
            Local Time:
            4:29 AM
            Spring 2806077 specs in the A engine MP book.
            Anybody have a big block book?
            image.jpg
             
          • rustycowll69

            rustycowll69 Well-Known Member

            Messages:
            2,208
            Likes Received:
            1002
            Joined:
            Feb 19, 2016
            Location:
            Pacific northwest
            Local Time:
            1:29 AM
            possibly true, maybe partly the reason. I always thought it was because all the exhaust valve train pieces are subjected to more conducted heat so they allow for more expansion by increasing the lash spec.
             
            • Thanks! Thanks! x 1
            • Agree Agree x 1
            • Daves69

              Daves69 FABO Gold Member FABO Gold Member

              Messages:
              4,941
              Likes Received:
              3065
              Joined:
              Feb 20, 2011
              Location:
              WestOfChi
              Local Time:
              3:29 AM
            • yellow rose

              yellow rose Doctor of Thinkology.

              Messages:
              22,299
              Likes Received:
              18331
              Joined:
              Jun 19, 2015
              Location:
              Living on the razors edge
              Local Time:
              1:29 AM
              I never ever run any lash that loose. Ever. Back then they used a long, slow lash ramp because springs were marginal and valves were super heavy.

              You can lash them at .022 hot on both sides and be done with it. Anything else is way too loose.

              Once you are confident you have the hot lash set correctly, you can let the engine get cold, and then measure the lash again.

              Whatever it is cold is what it is and from that point forward you can lash the valves cold.

              If you do it this way, you'll end up with a valve lash that is much more consistent. This is because when lashing them hot the engine is actually cooling off fairly quickly. If you are even fairly handy with a feeler gauge, you can test this.

              When you cold check your lash you'll see the valves you lash last are the tightest, because they were the coldest when you got to them. The very first valves lashed will be looser cold.

              Try it.
               
              • Agree Agree x 1
              • PRH

                PRH Well-Known Member

                Messages:
                2,163
                Likes Received:
                3310
                Joined:
                Dec 14, 2018
                Location:
                So. Burlington, Vt
                Local Time:
                4:29 AM
                P2806077....... I wouldn’t use them on anything.

                There are tons of better springs available.

                The 557 cam has no unique requirements....... just have whoever is doing the heads use springs suitable for any other flat tappet cam in that lift range.
                140/350-ish, depending on how high you plan on turning it.
                 
                • Like Like x 1
                • Agree Agree x 1
                • roccodart440

                  roccodart440 Well-Known Member

                  Messages:
                  5,527
                  Likes Received:
                  4548
                  Joined:
                  Apr 19, 2010
                  Local Time:
                  4:29 AM
                  I'd try what Yellow Rose suggested.

                  I've run mine for decades at .024/.028 safely (with aluminum heads) The engines were all run on dynos and checked hot as well. I don't know what the hot lash was but one thing is for certain. You can safely run them tighter than .028/.032.
                   
                • rumblefish360

                  rumblefish360 So close, yet so far away FABO Gold Member

                  Messages:
                  38,129
                  Likes Received:
                  9794
                  Joined:
                  Jun 21, 2005
                  Location:
                  New York, on a Island
                  Local Time:
                  4:29 AM
                  Have you ever run them tighter?
                   
                • roccodart440

                  roccodart440 Well-Known Member

                  Messages:
                  5,527
                  Likes Received:
                  4548
                  Joined:
                  Apr 19, 2010
                  Local Time:
                  4:29 AM
                  I've gone .024 on both.
                   
                  • Thanks! Thanks! x 1
                  • Red_Duster

                    Red_Duster Well-Known Member

                    Messages:
                    271
                    Likes Received:
                    163
                    Joined:
                    Apr 17, 2019
                    Location:
                    California
                    Local Time:
                    1:29 AM
                    I snugged them down to .025/.028 Saturday. might be in my head but seems a bit quieter than the .028/.032
                     
                  • roccodart440

                    roccodart440 Well-Known Member

                    Messages:
                    5,527
                    Likes Received:
                    4548
                    Joined:
                    Apr 19, 2010
                    Local Time:
                    4:29 AM
                    Not in your head.
                     
                    • Agree Agree x 2
                    • trapster

                      trapster Well-Known Member

                      Messages:
                      2,587
                      Likes Received:
                      220
                      Joined:
                      Feb 19, 2009
                      Location:
                      Central Florida
                      Local Time:
                      4:29 AM
                      I broke my cam in with the stock 340 valve springs, on my 284/484 cam, then left them in. they seem to be fine. but I also have Rhodes lifters .
                       
                    • rustycowll69

                      rustycowll69 Well-Known Member

                      Messages:
                      2,208
                      Likes Received:
                      1002
                      Joined:
                      Feb 19, 2016
                      Location:
                      Pacific northwest
                      Local Time:
                      1:29 AM
                      I did the same, but I had oem style 340 lifters
                       
                    1. This site uses cookies to help personalize content, tailor your experience and to keep you logged in if you register.
                      By continuing to use this site, you are consenting to our use of cookies.