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Vortec Head Modification/Upgrade

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  • Vortec Head Modification/Upgrade

    As some readers may be aware, I had trouble this season w/ broken rocker arm studs. I broke a total of (4) studs over the course of this season.
    I rebuilt this engine myself over last winter and incorporated some upgrades LCQ Pistons, bored 0.040, decked the block to achieve a ~0.040 quench, installed roller rockers and last but not least a CompCams XM270HJR cam. The machinist installed springs he said should have been OK. Well after a season of replacing broken studs I finally found the reason.....coil bind on the intake valves, all stud failures were on the intake valves, See pics below.

    I'm going to try and document the changes I am going to make.
    I Plan on changing the springs to CompCams 986-16 which will require some machining I am going to attempt to do myself and also replace the push-in studs w/ ARP 134-7104 studs.
    I have a set of not so great heads I am going to experiment on and share some pics.
    Last broken stud. Coil Bind
    '84 Grady White Offshore
    350 Mag w/ Vortec Heads
    Alpha 1 Drive

  • #2
    Look forward to it

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    • #3
      There's a poster on here who understands the coil bind issue. Scott Danforth. This ain't rocket surgery. Read his posts.

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      • #4
        Did some experimenting last night.........removed 2 valves and rocker studs.
        Machined down the rocker stud bosses and drilled and tapped to 7/16-14.
        Bought some cheap studs from ACE H/W just for kicks.

        Going to try the tool for the valve seat/guides today!
        '84 Grady White Offshore
        350 Mag w/ Vortec Heads
        Alpha 1 Drive

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        • #5
          Following this with interest Tony!
          It will for sure help out those who want to hot rod their own boat engines, and not just do a standard re-power.
          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"

          Comment


          • #6
            Install everything and recheck for coil bind, You usually cut the base of the spring pocket
            NO PERSONAL QUESTIONS, THIS IS WHAT THE FORUM IS FOR.

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            • #7
              http://www.lunatipower.com/Tech/Valv...pringTech.aspx
              NO PERSONAL QUESTIONS, THIS IS WHAT THE FORUM IS FOR.

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              • #8
                https://www.google.com/search?client...w=1280&bih=888
                NO PERSONAL QUESTIONS, THIS IS WHAT THE FORUM IS FOR.

                Comment


                • #9
                  Thanks for the links.
                  I have done research on the installed ht vs lift vs coil bind already.
                  Going to cut the seat and guide on the sample heads and measure installed ht.
                  '84 Grady White Offshore
                  350 Mag w/ Vortec Heads
                  Alpha 1 Drive

                  Comment


                  • #10
                    Originally posted by FreeBeeTony View Post
                    Thanks for the links.
                    I have done research on the installed ht vs lift vs coil bind already.
                    Going to cut the seat and guide on the sample heads and measure installed ht.
                    Don't cut too deep and get into a water jacket.

                    Comment


                    • #11
                      surprised you didn't leave this in your other thread to effectively bring that to a close

                      if you are running roller rockers, you wont need guide plates. if your running ball/socket rockers, you will need guide plates

                      the tech line at comp can give you exactly how much to cut the heads for the 986 spring.

                      Cheesehead boating the Gulf Coast of FLA 27.51° N, 82.53° W

                      1988 Cruisers Rogue 2420 -VP 290 DP now powered by custom 468 - https://forums.iboats.com/forum/owner...988-rogue-2420

                      Past Boats
                      1970 Wooster Hellion - Merc 9.8
                      2002 SeaRay 190BR - 5.0 - A1G2 - "Cheeseheads in Paradise"
                      1984 Avanti 170DLI -3.0 stringer- "Ship Happens"

                      What’s behind you doesn’t matter.Enzo Ferrari

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                      • #12
                        Going to run roller rockers......so no guide plate needed.
                        Will contact Comp Cams when ready, thanks.
                        Haven't had the chance to try that tool yet!
                        '84 Grady White Offshore
                        350 Mag w/ Vortec Heads
                        Alpha 1 Drive

                        Comment


                        • #13
                          Tried the guide/seat cutter tonight.........
                          Bought a expander tool a caliper to measure installed height when ready.
                          Cut the seat/guide on 1 intake valve as a test of the cutter,,,,,,seemed to work very well.
                          I installed a spring from ACE H/W w. the stock Vortec retainer just as a test......didn't check installed height at this point, need actual retainer and locks for that.
                          Also, bought a cheap drill press from Harbor Freight.......seems to be adequate for this project, a bit tough to get the right angle though.
                          '84 Grady White Offshore
                          350 Mag w/ Vortec Heads
                          Alpha 1 Drive

                          Comment


                          • #14
                            UPDATE:

                            Continuing to experiment w/ my "sample" head.
                            Turned down the seat and guide on 1 cylinder and machined down the rocker stud bosses and tapped..
                            Pics below are of springs and studs installed........not too shabby.........a little time consuming though! I'm actually enjoying it so far,,,

                            S question: can I simulate a 0.503" lift w/o the head installed and the cam creating the lift?

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

                            Comment


                            • #15
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                              Interesting you can see how the tool allows the valve springs the proper travel they need....
                              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"

                              Comment

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