Spun a rod

Discussion in 'Technical' started by Mott Power, Mar 24, 2006.

  1. I've heard this before, just have no idea what it means. I'm guessing it refers to the Con-rod.
  2. you mean spun a bearing?
  3. i dunno, maybe
  4. i thought bearings were supposed to spin :p
  5. Only some bearings like those found in turbochargers are supposed to spin. Most of them are designed to be stationary, if you look at an engine main bearing you can see that it's designed to prevent spinning.
  6. Yeah, you spin bearings and throw rods <A BORDER="0" HREF="http://www.supercars.net/PitLane?displayFAQ=y"><IMG BORDER="0" SRC="pitlane/emoticons/tongue.gif"></A>
  7. the people that say "spun a rod" are usually backwoods rednecks or people who think they know what they are talking about.

    I spun a main thrust bearing in my old 305, it creates a very rough surface on an otherwise smooth and almost polished surface designed to greatly reduce friction and provide an uninterrupted surface for oil to gather and create a layer between the bearing and the actual crankshaft journal. If these polished surfaces get gouged up or "spun" it disrupts this process. Also, a bearing may shift or "spin" inside the rod journal, if you look closely at a rod journal or crank jounal bearings go one way and one way only, there are notches in the caps or rod that the bearing must fit accordingly. If the bearing moves then it will be pushed out and touch the journal, even at a 600rpm idle this causes bad things to happen.

    Spun bearings can caused by a number of things, improper assembly, overheating, low to no oil, excessive timing advance (early combustion can lead to a lot of stress on bearings if you are firing while the piston is still coming up) , and abnormal stress to the rotating assembly such as a too far out of balance setup.

    Throwing a rod is a much more violent malfunction. Which results completely destroyed engines.

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