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Isky ST5 specs

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  • Engine: Isky ST5 specs

    I was fortunate to acquire an unused Isky ST5 cam complete with lifters and springs. Unfortunately it did not come with a cam card. I called the helpful folks at Isky and here is what the tech told me (hopefully I wrote it down correctly):

    Lift .448 @ .018 lash hot

    Specs @ .020 lift

    268 advertised duration
    110 LSA
    107 intake centerline

    IVO - 26 BTDC
    IVC - 62 ABDC
    EVO - 62 BBDC
    EVC - 26 ATDC

    The tech also indicated that there was 3 degrees advance built into the cam. I believe the specs are the same for the regrinds. From the markings on the cam, the tech was able to confirm that this is NOS, ground in 1974.
    78 Avanti RQB 2792
    64 Avanti R1 R5408
    63 Avanti R1 R4551
    63 Avanti R1 R2281
    62 GT Hawk V15949
    56 GH 6032504
    56 GH 6032588
    55 Speedster 7160047
    55 Speedster 7165279

  • #2
    Those specs are also pretty close to what Fairborn sells as the R2+ cam.

    jack vines
    PackardV8

    Comment


    • #3
      If you degree it in, you will find it is 3 crank degrees or 1 1/2 cam degrees retarded. I use the Chrysler 4 degree advance key to get a little more low end.

      Comment


      • #4
        Thanks Alan, good to know.
        78 Avanti RQB 2792
        64 Avanti R1 R5408
        63 Avanti R1 R4551
        63 Avanti R1 R2281
        62 GT Hawk V15949
        56 GH 6032504
        56 GH 6032588
        55 Speedster 7160047
        55 Speedster 7165279

        Comment


        • #5
          Or my adjustable cam drive...
          Have one left..(out of 20) !

          Mike

          Comment


          • #6
            Your actual operating degrees of duration will be off slightly. The specs. are .025" clearance, so you still have .005" to close up before the valve starts moving. I used to run my drag cars at .020" and when you needed a little extra power, drop it to .018" but only for short duration spurts like the drags. Don't drive it on the street that tight.

            Comment


            • #7
              I was thinking it might be different that the stock R1/R2 cam. I thought I read somewhere where the recommended R2+ lash was starting @ .020 down to .010. Maybe because it is a regrind? I don't want to round off the cam or burn a valve - so I am amenable to set the lash at .025 and see what I get.
              78 Avanti RQB 2792
              64 Avanti R1 R5408
              63 Avanti R1 R4551
              63 Avanti R1 R2281
              62 GT Hawk V15949
              56 GH 6032504
              56 GH 6032588
              55 Speedster 7160047
              55 Speedster 7165279

              Comment


              • #8
                According to my Isky catalogue, the ST5 cam has a duration of 268 deg. and a lift of .448 and 228 deg duration at .050 lift with a valve lash of.018. I have an ST5 cam in my Avanti and I've been using an .018 setting for years. Studebaker R series cams as originally installed use a valve lash of .023 to .025" hot. Using a setting of.025 with an Isky cam will produce a bunch of valve train noise. Bud

                Comment


                • #9
                  Reground cams have different opening ramps and do not require the same as stock lash settings. UNLESS, it is an EXACT stock replacement grind. I don't know of ANY that are. They all put their own profiles on as the machinery runs off a master blank.
                  I have never heard of any completely cnc cam grinding machines.
                  Bez Auto Alchemy
                  573-318-8948
                  http://bezautoalchemy.com


                  "Don't believe every internet quote" Abe Lincoln

                  Comment


                  • #10
                    so, do I run .018 as per Isky or .025 as per the stock Studebaker cam?
                    78 Avanti RQB 2792
                    64 Avanti R1 R5408
                    63 Avanti R1 R4551
                    63 Avanti R1 R2281
                    62 GT Hawk V15949
                    56 GH 6032504
                    56 GH 6032588
                    55 Speedster 7160047
                    55 Speedster 7165279

                    Comment


                    • #11
                      If you use the Isky cam, use .018" valve lash. .025" is used on an original equipment Studebaker cam. Bud

                      Comment


                      • #12
                        What ever is on the card. If .018" then you will have a little more duration than the card. I would have to go and look at my records, maby it was the RB7000 that had the .025" like stock Stude. To get even more duration use Rhoads Lifters and set them at 0. I did that with Lional Stones motor in his Avanti and it has been running for over 40 years with them.

                        Comment


                        • #13
                          bezhawk -

                          Yes, most modern cam grinders use..."completely" CNC machined cams.
                          Just not on everyday cast iron cams... On modern high end roller cams...absolutly.

                          Mike

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