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2008 Suzuki DF 70 (4stroke) : cracked cylinder head : worth replacing ?

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  • 2008 Suzuki DF 70 (4stroke) : cracked cylinder head : worth replacing ?

    Hi,

    Sea water was mixing with engine oil.

    Cylinder-head has cracks on the surface mating with the top of the block (which has no scatch).
    Craks are only arround the area that face the two bottom cylinders (sea pics).

    Any idea of the cause ?

    Some friend says it could be sea water coming up through open exhaust valves (which apparently occurs on low mounted engines). But I'm sceptical : no damage on the cylinder walls or piston heads.

    Is it worth replacing the cylinder head ($1600 bare) ?

    Thanks


    Here is some history about the engine that may help :
    - 30 hours only, but stood still for 8 months, laid on one side with oil in. Pistons stuck when I got it ;
    - removed power-head and cylinder-head. Found oil had made its way into the two bottom cylinders and had turned like varnish ;
    - cleaned and freed pistons. Noticed craks on the cylinder head but not bits of metal in the cylinders or in engine oil. No scratch on the cylinder walls ;
    - hooked everything back up with new gaskets ;
    - Engine ran fine for 5 hours (checked oil every 30 mn). Then noticed sea water was mixing with engine oil.
    Attached Files

  • #2
    Re: 2008 Suzuki DF 70 (4stroke) : cracked cylinder head : worth replacing ?

    Looks like corrosion problem, maybe a welder could build up those areas and re-surface? Might be worth a try before laying out big$$$ for new head. Some of the 4 stroke experts on here may have some other ideas for you. Good luck and let us know what you decide to do!

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    • #3
      Re: 2008 Suzuki DF 70 (4stroke) : cracked cylinder head : worth replacing ?

      Thanks.

      Welding seems an option - depending on the quality of the welding : if bits of metal fall down in the cylinder, the engine's dead.

      Has someone ever successfuly tried this ?

      Comment


      • #4
        Re: 2008 Suzuki DF 70 (4stroke) : cracked cylinder head : worth replacing ?

        I would have taken it to a machine shop and checked if possible to mill down to clean sealing surface for the head gasket.
        Might look worse than it really is.
        Go up yo 93 Oct, run the CO sensor to re-adjust injection and go boating!!

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        • #5
          Re: 2008 Suzuki DF 70 (4stroke) : cracked cylinder head : worth replacing ?

          Found a shop that says they can weld the head and rectify everything (head surface, valve seats, valves) for approx $800.

          Seems quite a lot but I think I'll give it a try since bare new head is $1600 and I'd have to properly adjust the old valves to the new seats myself.
          I'd rather leave that job to properly equiped professionals.

          It will take quite a lot of time cause I need to send the head far from where I live. Will keep you informed.

          I'm still interested in your ideas about the causes that damaged this cylinder-head...

          Comment


          • #6
            Re: 2008 Suzuki DF 70 (4stroke) : cracked cylinder head : worth replacing ?

            Tao,

            I have a 1999 DF60 and pulled the head yesterday for the second time. These heads are made of inferior metal, in my opinion. Anyway, 800.00 seems pricey, last time I had mine fixed, filled and surface only, for $100.00. I plan to do the fill and surface again this time and will buy a Yamaha if it happens again.

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            • #7
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              • #8
                Re: 2008 Suzuki DF 70 (4stroke) : cracked cylinder head : worth replacing ?

                Yea well, I'm working on mine currently, and you absolutely have to lift the power head to pull the cylinder head.
                I'm fighting the water in the oil problem. The head does not look bad. there is hardly any pitting and no sigh of a leaky head gasket other than the oil issue. It passes the straight edge test and was running good. Tomorrow I will take a look at the block, and maybe finish pulling the short block to check the pan.

                KP

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                • #9
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                  Re: 2008 Suzuki DF 70 (4stroke) : cracked cylinder head : worth replacing ?

                  Did you check the base of the power head for corrosion?
                  Did you check the zinks that are mounted in the head?
                  If you let the zinks go, the head will follow!

                  KP

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