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Vortec Head Modification/Upgrade

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  • #61
    True, they should have verified that those springs would work with the cam lift. And that information was available from the cam manufacturer anyway. Well now Tony you are the iboats expert on coil bind! Anyone who wants to use a high performance camshaft can ask you what to do!
    1988 Four Winns 200 Horizon
    4.3 OMC Cobra

    98 Jeep Grand Cherokee 4.0 Selectrac
    07 Jeep Grand Cherokee Limited 5.7 Quadradrive II

    "While air doesn't freeze....rust never sleeps"

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    • #62
      1st head completed: screw-in studs & new springs installed.
      Looking forward to spring......and working on the 2nd head!



      '84 Grady White Offshore
      350 Mag w/ Vortec Heads
      Alpha 1 Drive

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      • #63
        Ayuh,..... Lookin' good Tony,......

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        • #64
          Out of curiosity, why did you not use the beehive springs with their retainers to get the additional valve clearance?

          I talked to comp cams about running this same cam with vortec heads and that is what they told me to do.

          I did not read this entire thread, so sorry if this has already been discussed.

          wR

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          • #65
            I just read through the rest of the thread. So when the machine shop did the original work for you it sounds like they put on the beehive springs....is that correct?

            I was told by the tech at comp cams that would create plenty of lift for the XM270HR cam.

            Any idea why that did not work?

            wR

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            • #66
              My machine shop did not install the Beehive springs from CompCams, he had the springs and told me they should work, not sure what springs he used and I didn't check for coil bind when I assembled the engine. I decided to go with the "old-school" springs; they were less expensive. I would definitely check the clearance of the retainer to the valve guide when installing the Beehive springs. Notice that the CompCams webpage says machining is required. Make sure the tech you speak to at CompCams knows you're installing the springs on Vortec heads. I will try to answer any questions you may have. Might also want to consider changing to screw-in rocker studs.
              '84 Grady White Offshore
              350 Mag w/ Vortec Heads
              Alpha 1 Drive

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              • #67
                Wanted to highlight these things I learned along my journey:


                1) Another difference between Vortec valves and the earlier non self aligning head valves is the tip length. Earlier valves are 0.250" on both intake and exhaust valves. Self aligning head intake valves have a 0.260" groove-to-tip length, exhaust valves use a 0.289" groove-to-tip length. That said, the typical SBC valve tip length of 0.250" will work just fine with self aligning rockers. Like with ANY rocker arm/valvetrain combination, the
                valve train geometry
                needs to be verified.

                2) WarningNote:
                On Vortec and other heads using self aligning rocker arms, using a +0.050" lock can cause interference between the rocker tip and the locks/retainer. Rocker contacting the locks/retainer has been encountered using a combination of c/n 906 Vortec heads, Comp Pro Magnum rockers p/n 1317, Comp retainer p/n 787, Comp spring p/n 26918, and the +0.050" locks.

                The engine builder must mock up the assembly and check the clearance closely. In the case there's insufficient clearance, there are a few options:
                • Use non self aligning rocker arms. Requires guide plates be installed.
                • Use longer valves
                • Use a different spring/retainer combo that uses a standard lock
                • If just the locks are hitting the rocker, using a shorter (lash cap compatible) lock like the Edelbrock p/n 9615 may help. This 7 degree lock is 0.050" lower than a regular lock.
                • Warning Use extreme caution if making the spring seat any deeper.

                I contacted CompCams and their response was that they have not heard of the problem as I described.


                3)
                The Vortec head features a very large boss at the base of the valve guide that measures 0.850-inch in diameter and is used to locate the 1.250-inch outside diameter (O.D.) valve spring. The head uses 0.560-inch I.D. seals mounted directly on the top of the guide. This guide boss is also very tall. This height restricts the room between the top of the seal and the bottom of the valve spring retainer at max valve lift. There are two simple approaches to modifying the head to accept a performance valve spring that will create the room necessary to allow greater valve lift.

                4)
                The second solution is less expensive but requires more effort and to purchase a machine tool to modify the valve guide boss to add clearance. COMP sells a slick little tool that will machine the guide down to a 0.530-inch O.D. seal size while also lowering the boss height. The boss height of our heads measured 0.730-inch from the spring seat. It is this height that minimizes the seal-to-retainer clearance. With the tool set up in our ½-inch drill motor, it took a few minutes to machine all 16 guide bosses, being careful to lower the guide height only enough to create 0.550-inch retainer-to-seal clearance.

                I found these (4) bits of info on the internet and cut/pasted them here. Hope this helps.........
                '84 Grady White Offshore
                350 Mag w/ Vortec Heads
                Alpha 1 Drive

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                • #68
                  ugh, thanks for the info.

                  I guess I need to take everything those techs from Comp Cams say with a grain of salt.....and make sure to read the fine print.


                  wR

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                  • #69
                    Yes, the techs at CompCams did not know of all the intricacies that are encompassed within the Vortec heads.

                    Here is a link to where I got a lot of the info I found:

                    http://www.crankshaftcoalition.com/w..._cylinder_head
                    '84 Grady White Offshore
                    350 Mag w/ Vortec Heads
                    Alpha 1 Drive

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                    • #70
                      I would go with longer valve stems before I make my guides shorter. The guide is going to be subjected to more wear with a larger cam and making it shorter isn't going to help matters.
                      1999 Powerquest 260 legend
                      502 mpi
                      B1

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                      • #71
                        Originally posted by scoflaw View Post
                        I would go with longer valve stems before I make my guides shorter. The guide is going to be subjected to more wear with a larger cam and making it shorter isn't going to help matters.
                        That would require a "valve-job".........correct?
                        New seats etc.....?
                        '84 Grady White Offshore
                        350 Mag w/ Vortec Heads
                        Alpha 1 Drive

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                        • #72
                          The valve face is the same, the stem is longer. So if your seats are good now the longer stem isn't going to change anything. You will then probably need longer pushrods as well when you fine tune the rocker geometry
                          1999 Powerquest 260 legend
                          502 mpi
                          B1

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                          • #73
                            Originally posted by scoflaw View Post
                            The valve face is the same, the stem is longer. So if your seats are good now the longer stem isn't going to change anything. You will then probably need longer pushrods as well when you fine tune the rocker geometry
                            Longer? I would think if the valve stem is longer, that would push the rocker up higher at the valve end, which means lower at the rod end. So you'd need shorter rods..... Am I wrong somehow?

                            Chris...
                            Last edited by achris; January 10th, 2019, 06:23 PM.
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                            1972 Bertram ‘Bahia Mar’ 20
                            2006 Mercruiser 4.3MPI (0W617679) w/Alpha One Gen II (0W829301)
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                            • #74
                              This is where the adjustable pushrod comes in to figure out what length your looking for according to the pattern on top of the valve stem.
                              1999 Powerquest 260 legend
                              502 mpi
                              B1

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                              • #75
                                Sign up today
                                2nd Head machining complete except for tapping the rocker studs; hope to do that tomorrow.

                                '84 Grady White Offshore
                                350 Mag w/ Vortec Heads
                                Alpha 1 Drive

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