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Caterpillar 3412c

Discussion in 'Engines' started by searage, Mar 2, 2014.

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  1. searage

    searage Member

    Joined:
    Oct 12, 2010
    Messages:
    33
    Location:
    South Miami, Florida
    Good afternoon, i am considering the purchase of a 1997 CAT 3412c powered vessel with an early engine code below 3JK00880. In 1998 CAT issued a technical bulletin reference changes to the heads. The dowel bridges were replaced with new heads that had dowel-less bridges. The bulletin warned of using the older valves on the newer heads. If the incorrect valves were used it could cause premature failure of the valves. Does anyone on the forum know why the change to the dowel-less design took place. Are the early engines with dowel heads reliable?
  2. CatTech

    CatTech New Member

    Joined:
    Sep 28, 2010
    Messages:
    56
    Location:
    south FL
    The doweled valve bridge adds an additional adjustment to the valve adjustment procedure. If these adjustments are not checked often enough and done correctly it can cause the bridge to stick on the dowel causing a failure.
  3. Capt Ralph

    Capt Ralph Senior Member

    Joined:
    Sep 8, 2004
    Messages:
    12,649
    Location:
    Satsuma, FL
    I would think this is not a problem with the engine, rather, making sure the correct and correctly informed tech is doing any adjustments or service. I'm thinking the OP is concerned of taking over these engines.

    I'm not a Cat guy like CatTech & others, but I love ole proven engines.
    I have been on one ship with 3412s and loved them.
    Actually miss them. I think it's a good design.
    C rated should run for a long while. The Boat I was on was E rated but idled everywhere AND still took the abuse very well.