1978 401 Valve Springs Help

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  • Wagoneer Taylor
    258 I6
    • Dec 17, 2018
    • 434

    1978 401 Valve Springs Help

    Hey guys,

    For some reason I am having a heck of a time finding valve spring info.

    More over, what is stock specs?

    If anyone can point me in the right direction or let me know what you used?

    I am building a completely stock 401 internally, but I would like to use dampened springs.

    Thanks,
    Taylor
    Some call me Taylor...

    1977 Jeep Wagoneer (Wedding Wagon)
    Pewter, Blue Interior, Original 401
    PO swapped in a 360, soon to be a 401 again!
    "Soon" is a relative term.
    Cracked cylinder put a hurt on me + bad connecting rods.
  • Cliff
    350 Buick
    • Mar 30, 2002
    • 864

    #2
    My 1981 Chilton's manual has valve spring specs for the 401 but only up to 1974. It's an "auto" manual so it doesn't include Jeeps, and 74 was the last year for the 401 in cars. But I can relay the 74 specs if you think it will be of any value.
    Cliff Danley
    1977 Cherokee S

    Comment

    • Wagoneer Taylor
      258 I6
      • Dec 17, 2018
      • 434

      #3
      Originally posted by Cliff
      My 1981 Chilton's manual has valve spring specs for the 401 but only up to 1974. It's an "auto" manual so it doesn't include Jeeps, and 74 was the last year for the 401 in cars. But I can relay the 74 specs if you think it will be of any value.
      Thanks Cliff, I am sure it couldnt hurt to have the specs on 74.

      Please share.
      Some call me Taylor...

      1977 Jeep Wagoneer (Wedding Wagon)
      Pewter, Blue Interior, Original 401
      PO swapped in a 360, soon to be a 401 again!
      "Soon" is a relative term.
      Cracked cylinder put a hurt on me + bad connecting rods.

      Comment

      • SC/397
        Administrator
        • Feb 01, 2010
        • 1024

        #4
        You might be able to find it faster if you looked up valve springs for a 360.
        The 360 and 401 use the same cylinder heads.
        For a stock application, I usually buy these and eliminate the rotators.
        AMC Engines. Set includes 16 springs. Jeep Engines. 401 CID (6.6L) 1978. 360 CID (5.9L) 1978-1990. 304 CID (5.0L) 1978-1981.


        I will see if I can find more info for you.
        The Squeaky Wheel gets replaced in my world

        Comment

        • Wagoneer Taylor
          258 I6
          • Dec 17, 2018
          • 434

          #5
          Originally posted by SC/397
          You might be able to find it faster if you looked up valve springs for a 360.
          The 360 and 401 use the same cylinder heads.
          For a stock application, I usually buy these and eliminate the rotators.
          AMC Engines. Set includes 16 springs. Jeep Engines. 401 CID (6.6L) 1978. 360 CID (5.9L) 1978-1990. 304 CID (5.0L) 1978-1981.


          I will see if I can find more info for you.
          Hey SC/397, I should have reached out to you! You having built about a million on these.

          Do you use or know of a set that has the damper in them but would be a nearly stock pressure?

          I will look into 360 springs as you mentioned too
          Some call me Taylor...

          1977 Jeep Wagoneer (Wedding Wagon)
          Pewter, Blue Interior, Original 401
          PO swapped in a 360, soon to be a 401 again!
          "Soon" is a relative term.
          Cracked cylinder put a hurt on me + bad connecting rods.

          Comment

          • Wagoneer Taylor
            258 I6
            • Dec 17, 2018
            • 434

            #6
            Originally posted by SC/397
            You might be able to find it faster if you looked up valve springs for a 360.
            The 360 and 401 use the same cylinder heads.
            For a stock application, I usually buy these and eliminate the rotators.
            AMC Engines. Set includes 16 springs. Jeep Engines. 401 CID (6.6L) 1978. 360 CID (5.9L) 1978-1990. 304 CID (5.0L) 1978-1981.


            I will see if I can find more info for you.
            Another question, why do you eliminate the rotators?
            Some call me Taylor...

            1977 Jeep Wagoneer (Wedding Wagon)
            Pewter, Blue Interior, Original 401
            PO swapped in a 360, soon to be a 401 again!
            "Soon" is a relative term.
            Cracked cylinder put a hurt on me + bad connecting rods.

            Comment

            • SC/397
              Administrator
              • Feb 01, 2010
              • 1024

              #7
              I guess the main reasons I eliminate the rotocaps is because the early engines didn't have them and because it is harder to find the shorter springs.
              Also, there is less of a problem with coil bind if you are using a slightly higher lift cam.
              The Squeaky Wheel gets replaced in my world

              Comment

              • Wagoneer Taylor
                258 I6
                • Dec 17, 2018
                • 434

                #8
                Originally posted by SC/397
                I guess the main reasons I eliminate the rotocaps is because the early engines didn't have them and because it is harder to find the shorter springs.
                Also, there is less of a problem with coil bind if you are using a slightly higher lift cam.
                So the springs you sent in the link are longer then stock?
                The problem I am having is I dont even know what size I should have in the first place?
                I am running a stock cam.
                Some call me Taylor...

                1977 Jeep Wagoneer (Wedding Wagon)
                Pewter, Blue Interior, Original 401
                PO swapped in a 360, soon to be a 401 again!
                "Soon" is a relative term.
                Cracked cylinder put a hurt on me + bad connecting rods.

                Comment

                • Cliff
                  350 Buick
                  • Mar 30, 2002
                  • 864

                  #9
                  I had mentioned that my Chilton's only included the 401 up to 1974, but I was wrong - it goes to 1976. Here are the specs:

                  outer spring test pressure 223 lbs @ 1.35"
                  spring installed height 1-13/16"

                  There is a separate spec for police engines:

                  outer spring test pressure
                  intake 270 lbs @ 1.38"
                  exhaust 270 lbs @ 1.19"

                  The test pressure specs for 1976 360 CID are 213 lbs instead of 223, same height
                  Cliff Danley
                  1977 Cherokee S

                  Comment

                  • SC/397
                    Administrator
                    • Feb 01, 2010
                    • 1024

                    #10
                    Those specs look about right. 1.800" installed height and around 100# on the seat. I think the lighter ones may have been around 80# on the seat.
                    The Squeaky Wheel gets replaced in my world

                    Comment

                    • Wagoneer Taylor
                      258 I6
                      • Dec 17, 2018
                      • 434

                      #11
                      Thanks guys, this is helping me narrow it down at least.
                      Some call me Taylor...

                      1977 Jeep Wagoneer (Wedding Wagon)
                      Pewter, Blue Interior, Original 401
                      PO swapped in a 360, soon to be a 401 again!
                      "Soon" is a relative term.
                      Cracked cylinder put a hurt on me + bad connecting rods.

                      Comment

                      • rang-a-stang
                        Administrator
                        • Oct 31, 2016
                        • 5456

                        #12
                        Chuck McTruck 71 J4000
                        (Chuck McTruck Build Thread)
                        79 Cherokee Chief (SOLD, goodbye old buddy)
                        (Cherokee Build Thread)
                        11 Nissan Pathfinder Silver Edition 4x4
                        09 Mazdaspeed3 Grand Touring
                        00 Baby Cherokee

                        Comment

                        • Wagoneer Taylor
                          258 I6
                          • Dec 17, 2018
                          • 434

                          #13
                          Originally posted by rang-a-stang
                          I dont know whether to laugh hysterically or

                          I am going with laugh!
                          Some call me Taylor...

                          1977 Jeep Wagoneer (Wedding Wagon)
                          Pewter, Blue Interior, Original 401
                          PO swapped in a 360, soon to be a 401 again!
                          "Soon" is a relative term.
                          Cracked cylinder put a hurt on me + bad connecting rods.

                          Comment

                          • SC/397
                            Administrator
                            • Feb 01, 2010
                            • 1024

                            #14
                            This is a really good How-to vid for you.
                            Blown Head gasket? Learn how to replace your head gasket and piston return springs so your car or truck can run and drive again! In this video I show you ho...
                            The Squeaky Wheel gets replaced in my world

                            Comment

                            • Wagoneer Taylor
                              258 I6
                              • Dec 17, 2018
                              • 434

                              #15
                              Originally posted by SC/397
                              This is a really good How-to vid for you.
                              https://www.youtube.com/watch?v=oFX_Xq9WHTI
                              Some call me Taylor...

                              1977 Jeep Wagoneer (Wedding Wagon)
                              Pewter, Blue Interior, Original 401
                              PO swapped in a 360, soon to be a 401 again!
                              "Soon" is a relative term.
                              Cracked cylinder put a hurt on me + bad connecting rods.

                              Comment

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