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coolant issue on 12 v 92s

Discussion in 'Engines' started by bluesuit, Feb 26, 2014.

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  1. Jimbo1959

    Jimbo1959 Member

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    Probably the pins that hold the lower washers in place on the main bearing cap broke or wore away. This allowed the washers to spin and eventually fall out.
    Thanks Jim
  2. rgsuspsa

    rgsuspsa Member

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    The largest number of cylinders of a single, V92 Series Detroit Diesel engine
    is sixteen. There never was a production 24V-92 configured as a single engine. It is true that multiple V-92 engines could be ganged together by gearboxes, however Detroit Diesel Corp. never released that configuration.

    The V71 Series did include a 24V-71 engine, consisting of two 12V-71 cylinder blocks coupled together in-line as in the case of the 16V-71, 12V-92 and 16V-92 engines.
  3. bluesuit

    bluesuit Member

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    Ron,
    Any opinion as to why the thrust washers would be chewed up and in the bottom of the oil sump? This is a real mystery to my mechanic!!!
  4. rgsuspsa

    rgsuspsa Member

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    bluesuit: As Jimbo1959 suggested, the two thrust bearing locating pins on the front and rear main bearing caps should be checked to determine if they are intact. If not, a thrust bearing (two, half-circle arcs of 180 degrees each comprising a complete bearing) at the front and rear of the crank would not be prevented from rotating with the crankshaft, and possibly could have worn away until they might have dropped into the oil pan. (I am assuming that your previous use of the term,"...washers...", referred to the half-circle arcs which comprise the thrust bearing.)

    Before I suggest possible alternate causes, please have your mechanic check
    the pins on each cap, and also confirm that the washers found are in fact the
    half-circle arcs which are the thrust bearings.
  5. bluesuit

    bluesuit Member

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    Ron,
    Mechanic said pins were wore down and that that half (rear) part of the block needs to be replaced. He thinks the crank shaft is in good shape with some work. The description you gave me is what they look like. Give me your email address and I can send you pics of them. By the way, can't find any new blocks. Was going to go with a used one that of course checked out, any opinion on that???
    Frank
  6. rgsuspsa

    rgsuspsa Member

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    Frank:

    With a 12V-92, the entire block assembly should be replaced.
    This consists of properly aligned front and rear blocks. MTU/Detroit Diesel
    has replacement longblocks available on a assemble to-order basis, which include all internal parts, and cylinder head assemblies. This may be the best course of action.
    Also, do a Google search for "Boats and Harbors", which is a
    advertising site for the commercial marine industry.
  7. Jimbo1959

    Jimbo1959 Member

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    What part of the block is damaged? Is it the saddle or the main brg cap? Pictures if possible would be nice
    Thanks Jim
  8. bluesuit

    bluesuit Member

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    The part of the block that is damages is where the thrust bearings meet the crankshaft.

    Attached Files:

  9. Capt Ralph

    Capt Ralph Senior Member

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    Is that a balancing grind on the crank throw or did something hit it? If collision, with something, scrap the crank.
  10. K1W1

    K1W1 Senior Member

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    Hi,

    If it got that dent from striking something the shaft might be bent which might explain why it spat the thrusts out.
  11. Capt Ralph

    Capt Ralph Senior Member

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    Yes, If that is a strike as it looks like it in the pic.
    I have never seen a balancing grind in that area before but I am not the 92 crank expert. If it truly is a strike, in my opinion, not repairable, no matter what your machine shop may say. There are too many vibrations already going on in a DD 2-stroke. You don't want to go thru this again. Toast the crank.
  12. bluesuit

    bluesuit Member

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    here's a pic of the block.
    the gouge in the counterweight looks suspect to me.

    Attached Files:

  13. bluesuit

    bluesuit Member

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    better pic of the block

    Attached Files:

  14. K1W1

    K1W1 Senior Member

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    Hi

    When the main brg shells are out is there any signs of fretting on the back or a lot of wear on one side of the bearing surface?

    If it were mine I would check the alignment of the block even if I was going to junk it just to see if I could find something definitive to blame for the thrust coming out.

    I have seen an engine rebuilt without thrusts by its Owner, the clutch was always going out of adjustment and there was metal in the oil. By the time the fault was discovered the retainer slot for the thrust was badly worn. The Owner operator did not have the cash for a new block so we drilled and screwed the thrusts onto the block. Never heard any complaints or problems in the next 4 yrs I worked in that shop.
  15. bluesuit

    bluesuit Member

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    yes, more wear on one side of the shell than the other.
  16. K1W1

    K1W1 Senior Member

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    If by this you mean fwd or aft side not top or bottom you have a bent crank.
  17. Capt Ralph

    Capt Ralph Senior Member

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    Wow. What an adventure.
    I'm not sure where that (suppose) strike on the crank came from. Was there a previous failure then slapped back together? I would not think a flying bearing part could do that.
  18. SomeTexan

    SomeTexan Member

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    There is no reason for that to be a balance mark, you always add/remove metal from the counterweights when balancing a crank. In the pic, it looks like it was made by solid contact with hard parts. I have seen a broken pushrod do similar damage in a different engine, makes me wonder what these engines have been through prior to your ownership. I am with everyone else, I wouldn't reuse the crank.
  19. Jimbo1959

    Jimbo1959 Member

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    I too would not use that crank, I would exchange it with recon from Detroit. As to the block, it should have those recesses at the rear main brg area. Those recesses are there to hold the upper thrust washers. But I see you have split the blocks apart. If those 2 blocks check out, you will need some special tools from DDA to assemble the blocks back together, very critical procedure for securing the blocks together. If your guy is unsure I wouldn't try it. BTW Detroit makes oversize thrust washers for blocks that have been machined.
    Jim
  20. bluesuit

    bluesuit Member

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    soot on transom

    Greetings Gang,
    Went fishing in GOM this weekend and we washed off a whole bunch of soot off the transom. Port engine is Brand new. Starboard about 2700 hours. No visible smoke while at cruise. What Y'all think?