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Cracked '99 5.7 Vortec Heads

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  • Cracked '99 5.7 Vortec Heads

    Bad news for me.

    During the last few trips we noticed a slight increase in steam out of the starboard hooter along with an occasional "fuel" smell on warm restart. I assumed it was just condensation as the engine ran great and temps were normal, unfortunately that wasn't the case.

    I was due for an oil and filter change and after it was done I checked the heat exchanger tank, sure enough it was down over a quart. I ran the engine on the hose and the starboard steam was slight but obvious. After pulling the spark plugs, I noticed the #2 plug was just a bit cleaner than the others. I had heard of some cracked Vortec heads but not enough to realize the problem was significant.

    I made a call to a favorite machine shop/engine builder (Derek at L&R Engines) and he confirmed my speculation by stating that 90% of the 5.7 Vortec heads he checks will not pass a magnaflux test. I asked his opinion on the GM Bowtie 185cc Vortec heads and the Edelbrock 170cc Etec heads, the two I was considering. Derek said both heads are very good but preferred the Etecs. I also asked his opinion on pulling the engine for complete rebuild at 1385hrs and he recommended just the heads at this time, adding that the Vortec shortblock is very durable.

    Fortunately, I was able to purchase all of the parts and received them within a few days. This included Etec 170s #60795, Melling lifters and rockers, Comp Cams pushrods (0.100" long due to the higher valve stem on Etecs), and gaskets.

    The upside may be a slight performance improvement
    Steve
    1998 260 Mackinaw Sea Maxx 5.7 HO TBI 12' Klamath w/ 20hp Tohatsu EFI

  • #2
    Thanks for the FYI on what’s going on with your Vortec. Interested in how much improvement you get. Good luck with the repairs
    Just wishin', and hopen', and dreamin'

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    • #3
      Thanks Greg. I had no idea the problem was so prevalent so I wanted to share the info. Otherwise, the 5.7 Vortec is such a great engine. I might have been able to run some of those GM radiator biscuits that Cadillac put in the awful Northstar engines....

      I'm not expecting a big change but I will share my results after a few test runs. I'll tear into it on the weekend.
      Steve
      1998 260 Mackinaw Sea Maxx 5.7 HO TBI 12' Klamath w/ 20hp Tohatsu EFI

      Comment


      • #4
        Heads are on. I ran the engine for 1/2 hour and it sounds perfect. The idle is smooth and the valvetrain is quiet, the TBI injectors are louder. The only potential issue with the Edelbrock heads is the exhaust flange sticks out a little more than the GM Vortec heads, the gap between the house wall and the manifolds is only about 1/4", maybe an 1/8" closer than before. Hopefully, I can sneak out for some testing next week.
        Steve
        1998 260 Mackinaw Sea Maxx 5.7 HO TBI 12' Klamath w/ 20hp Tohatsu EFI

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        • #5
          Why are the injectors louder? Any ideas?

          Thanks for the update.
          Just wishin', and hopen', and dreamin'

          Comment


          • tuner
            tuner commented
            Editing a comment
            The injectors are the same, the valvetrain is quieter with new lifters so the injector noise is more apparent.

        • #6
          Time to turn up the stereo!
          Karen
          Punxsutawney, Pennsylvania
          1986 Shamrock H/T with RWC 330 hp PCM, dual hydraulic helm
          1992 Mako 211CC w/Mercury Optimax 175
          3 other smaller OB boats and a trusty old canoe...

          Comment


          • tuner
            tuner commented
            Editing a comment
            LOL, I would need a serious sound system to hear over my 4" exhaust and Hooter "megaphones"!

        • #7
          Now there is a great reason to upgrade the sound system!
          Karen
          Punxsutawney, Pennsylvania
          1986 Shamrock H/T with RWC 330 hp PCM, dual hydraulic helm
          1992 Mako 211CC w/Mercury Optimax 175
          3 other smaller OB boats and a trusty old canoe...

          Comment


          • #8
            I like my current "sound system"......most of the time

            A switch that controlled the exhaust sound would be great, like "cut-outs' on a hotrod
            Steve
            1998 260 Mackinaw Sea Maxx 5.7 HO TBI 12' Klamath w/ 20hp Tohatsu EFI

            Comment


            • #9
              Sea trial today. The engine ran great,unfortunately, there was a 3-5' short period wind swell that hampered performance testing. I will need a nice day with smooth conditions and less crap in the water (recent rains have "flushed" the encampments and other trash, trees, etc.). I was getting a bit of oil smoke on start-up and the new heads may have fixed that too. Great throttle response and the idle seems smoother than before, maybe the new valve and seats get the credit. So far so good!
              Steve
              1998 260 Mackinaw Sea Maxx 5.7 HO TBI 12' Klamath w/ 20hp Tohatsu EFI

              Comment


              • #10
                The smoke on startup gone, guess the valve guide seal were starting to go dry. So you have that going for you!
                Happy New Year!
                Just wishin', and hopen', and dreamin'

                Comment


                • #11
                  After 21 years and 1385hrs the seals and seats were causing problems. The exhaust note is better too! It was a chore but worth it!

                  Happy New Year!

                  Steve
                  1998 260 Mackinaw Sea Maxx 5.7 HO TBI 12' Klamath w/ 20hp Tohatsu EFI

                  Comment


                  • #12
                    LOL any engine sounds better when the repairs work the way you expect them!

                    Happy New Year to you and family.
                    Just wishin', and hopen', and dreamin'

                    Comment

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