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Another cracked head!

Discussion in 'Ocean Yacht' started by praetorian47, Nov 1, 2019.

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  1. praetorian47

    praetorian47 Senior Member

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    Location:
    Bayport, Midland, Ontario
  2. Capt J

    Capt J Senior Member

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    Could the vessel have been poorly winterized?
  3. praetorian47

    praetorian47 Senior Member

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    Location:
    Bayport, Midland, Ontario
    It's In a heated building.
  4. chesapeake46

    chesapeake46 Senior Member

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    Chesapeake Bay, Delaware Bay & S.Jersey
  5. Capt Ralph

    Capt Ralph Senior Member

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  6. praetorian47

    praetorian47 Senior Member

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    The heat exchanger leaks were repairable! That's a relief! We ended up with 2 newly casted heads (I still can't get over the fact they are still made). Installing them in about 2 weeks. Not a huge hurry - 6 weeks until launch, at least.

    We're going to try to add a few sensors to better gauge what's going on.
  7. Capt Ralph

    Capt Ralph Senior Member

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    Did you figure out the head issue? Cracked? Injector tube?
    Can you share any pictures of your head failure.
    Have a bud with bubbles in the H/E now. Trying to explain to him where these bubbles come from.
  8. praetorian47

    praetorian47 Senior Member

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    I may still have some photos but the cracks occurred between cylinders and were very hard to see. Apparently these engines are known for this. A couple things I was told by a very knowledgeable DD mechanic: 8V92s crack heads, sometimes for no apparent reason. A stiched head WILL fail on these, don't use one (You can get new castings if you need them, that's what I did). A head that is a minimum thickness will fail (I don't know why minimum thickness isn't more).

    Now anybody can dispute these things, I'm just passing them along. Since I put new cast heads on, no problems.

    We never found anything wrong. What I suspect is that the previous owner did a coolant flush and bits of crap got loose and may have blocked the HE tubes and caused it BUT on the last one, there was no overheat - not even close. I have murphy gauges on with a high temp record.
  9. dennismc

    dennismc Senior Member

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    Vancouver BC
    I had a crack developing in a 12 v 71 n a few years after an injector tube failed at the same location, we caught it during an overhaul and scrapped it.
  10. Capt Ralph

    Capt Ralph Senior Member

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    Thanks all
    Just trying to find some pictures to help a non DDC mind, understand the issues he has with a 6V92 boat.
    Think I found some good stuff in a couple of old manuals.
  11. Boomer

    Boomer Senior Member

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    I thought you were retiring...again?
  12. Capt Ralph

    Capt Ralph Senior Member

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    Supporting a friend.
    Explaining 80+ year old diesel technology (2 stroke Detroits) to an atomic guy is rather difficult sometimes.
    Further explaining how bubbles can come out of an expansion tank cap can be a taller challenge.
  13. Boomer

    Boomer Senior Member

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    This weather sucks!!
  14. Capt Ralph

    Capt Ralph Senior Member

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    It was Fugly outside today. Going to suck till Friday Morning up here, Then start all over again.

    So, You all cleaned up and mobile?
    Any paint down yet?
  15. Boomer

    Boomer Senior Member

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    We have the rub rail and front of the house done..need to do some cockpit and bridge paint work next...then oil changes, impellors, motor zincs etc then we should be good to go! Ready to get away? We did get out last weekend for a run and she ran awesome...no complaints except the headache in the morning
  16. Capt Ralph

    Capt Ralph Senior Member

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    "except the headache in the morning"
    Mix with less cola and more water.