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998 Valve Job

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  • 998 Valve Job

    The return leg of a quick trip to Yellowstone found the '63 with a distinct lack of power and a truly nasty exhaust note. Compression? Cyl 1:zero, 2:192lb, 3:zero, 4:180lb.The head came off to find two burned exhaust valves and wads of carbon build-up. Too lean a mixture probably though DAILY checks of sparkplug color showed the desired soft serve chocolate color.
    What should I ask of Autosport when I take the head to them? Hardened valve seats of course but what else?
    998, 20 thou overbored (now I know), Maniflow exhaust, Howley intake with single HS4.

    Don

  • #2
    Just out of curiosity i did a WINSU input of your info on your setup and it recommended a ABD needle and yellow spring (does this apply with HS4)?...but i inputed info for the cam and rockers as standard setup not knowing what you have. And an ABD needle would get you at 1.8% lean on top end and 1.6 lean on mid range... pretty darn close... sorry its not really relevant to your post, but still.

    i have a new ABD needle and new yellow spring if you would like to try it out some time. let me know.

    good luck with getting everything repaired!

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    • #3
      New valve guides, maybe upgrading the valves from stock to more performance type. Or how about a nice port and polish job, new double springs and a set of roller rockers
      "remember, in this country, they drive on the wrong side of the road"
      ‘64 Austin Countryman-???
      '60's Austin mini truck - the chicken truck
      '60 Morris Van - Marvan
      '55 Chevy wagon- the heavy Chevy

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      • #4
        Thanks Tim, I'll plug my info into Win Su once I determine my final drive ratio (easy) and what cam I have (doable, I have some clues). The HS4 currently has a sprung ADD needle.
        Thanks James for your input.

        Don

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        • #5
          Just slightly on topic; possibly consider adding the correct bung to your exhaust mfld / header for post re-assembly data gathering from some sort of oxy sensor, especially on the dyno. I'm fully aware, I'm "spending your money", but just think of the accuracy you could attain by knowing your mixture under load.
          I offer this wild thought due to your concerns that mixture may have had a part in it's demise!

          Good luck, and Best regards,
          MSH
          All Together Now..... Everybody.......

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          • #6
            I like what James said, but a nice set of forged 1.3 rockers are a little less than half of what rollers cost. But surely open it up a little. Not sure of the benefit of dual springs for a street car though.

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            • #7
              Don't I remember that the lift is actually a little more with the stamped steel rockers than the forged ones? I second the bung-in-the-header idea.
              Ed

              1972 Austin 1300GT - Mean Mr. Mustard
              1963 Riley Elf MkII - Baba O

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              • #8
                Regarding the rockers, the forged ones are supposed to be more accurate and consistent regarding the lift ratio.

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                • #9
                  Wow what a nice head (besides the two burnt valves). Beautiful port job and now with some bronze guides with *** valve stem seals and a new set of SS valves. Ready for the next go round. Seals are from the distant German kins.
                  Last edited by MrBoring; 09-22-2009, 08:21 PM. Reason: because

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                  • #10
                    Now I won't be able to display a "100% free of *** parts" sticker.

                    Don

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                    • #11
                      Just say they're Volkswagen, DKW or Opel...
                      Skip

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                      • #12
                        So, Don...what was the result??

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                        • #13
                          The head was surfaced .004, new exhaust valves and all new guides. ARP studs are in hand. The exhaust manifold is out and will go down to Autosport for a bung.
                          I'm holding off installing to bring it to the next meeting for show and tell. There are some cryptic numbers stamped into the head, probably having to do with the port job, that need deciphering. I'll also bring an unmodified 12G295 (for sale, $175) for comparison.
                          Don

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                          • #14
                            Don, maybe I missed something. Who did the porting for you??

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                            • #15
                              You've heard of the Dreaded Previous Owner? The porting was done by the Benevolent and Kind Previous Owner, AKA my big brother Dave and his wife Zelda. The motor was built by former SAMOAN Roger Soucy. Don't know who did the head work for him.
                              Don

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