Thrust bearing block

Discussion in 'Boat Design' started by Wayne Kendall, Aug 16, 2012.

  1. Wayne Kendall
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    Wayne Kendall Junior Member


    To keep my engine low I am using 2 universal joints joined by a short stub shaft, with a thrust bearing block. My question - What should be the operating temperature of that thrust bearing?

  2. keysdisease
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    keysdisease Senior Member

    Whatever the manufacturer specify's as operating temp range.

  3. Petros
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    Petros Senior Member

    Typically, if it is directly attached to the engine, at continuous full throttle the crankshaft should not get hotter than about 200 deg F. If the cooling system overheats it might get a bit higher (like 40-50), but not much more before the engine stops running.

    MOst of the heat of a thrust bearing however would come from internally generated heat from the bearing friction. The better the quality of the bearing the lower the temp caused by frictional heating. IT is also important that the area around the bearing be considered for heat dissipation, either with good ventilation or cooling by conduction through the mounts.
  4. gonzo
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    gonzo Senior Member

    Oil bath bearing work at lower temperatures and can have a cooler incorporated. The bearing manufacturer specifies what the maximum temperature is.
  5. CDK
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    CDK retired engineer

    The fact that you asked that question already says something is wrong. The thrust bearing is a permanently lubricated, sealed ball- or tapered roller bearing that has very little friction so it will get lukewarm only. If yours is too hot to touch the bearing races are damaged or the alignment sucks.

  6. Wayne Kendall
    Joined: Aug 2012
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    Wayne Kendall Junior Member

    Thrust Bearing Temperature

    The thrust bearing block that I have in my boat is fairly old. I just recently took it out and poured new babbit because the shaft had a fair amount of play in the thrust block. I also checked the ball bearings, in my case there are 2 sets both enclosed in 2 collars, which slide over the shaft. They appeared to be moving freely and intact. Separating the bearings is another collar with 2 set screws. My alignment seems to be okay, however, the block do get hot after running for a couple of hours. Is it because I poured new babbit which makes a tight fit on the shaft that causes the bearing to get hot.

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