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#31
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"Jim Carter" writes:
I've torn engines down before and the distance between the rings is relatively a lot more than the gap between the ends of the ring when compressed into the cylinder. It is such a big difference that I don't see how the intra-ring distance could be restrictive to the flow of gasses passing through the ring gap. I'd really like to see some information on the "Very Clever Design" you mentioned. Even if the cylinders were honed with a diagonal pattern, shouldn't the ring just reverse direction at the end of the stroke and follow the honing marks? -- Jim Carter "David Lesher" wrote in message ... "Jim Carter" writes: What causes the piston rings to rotate? Since the piston movement is perpendicular to the cylinder wall, there must be some other mechanism other than just piston movement causing them to rotate. Very Clever Design. I can't recall the details, but ISTM there are [automotive] patents on making 'em creep along. Also, why would the grooves on the rings have to be lined up to allow leakage through the groove? It does leak lots more; the gap between the rings is not all that far, I guess... I don't recall much more. I'll ask a friend who knows lots more than I do on engine innards. But it was Detroit, not overseas... -- A host is a host from coast to & no one will talk to a host that's close........[v].(301) 56-LINUX Unless the host (that isn't close).........................pob 1433 is busy, hung or dead....................................20915-1433 |
#32
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The piston really only approximately goes straight up and down.
Engines are not perfect machines. If you looked at the general dynamic alignment of everything on the microinch level etc, there is probably a slight amount of rotation inherent in the structure of an engine including the crankshaft and rod deformations. When combined with the varying pressure fluctuations on each ring, the ring gradually rotates in one direction or another. Remember you are dealiung with something that is cycling back and forth 40 times per second, so that it doesn't take very much rotation each cycle to give a lot of eventual motion. Put it another way - why shouldn't it rotate? |
#33
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I don't think it should rotate because the action of scrubbing against the
cylinder walls will wear "micro" grooves in the rings that match up against corresponding ridges on the cylinder wall. If the rings rotated there would never be this ridge/groove result. Since you can see and sometimes feel the grooves and ridges, I can only assume the rotation of the ring is not happening. -- Jim Carter wrote in message om... .... Put it another way - why shouldn't it rotate? |
#34
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In article ,
"Jim Carter" wrote: I don't think it should rotate because the action of scrubbing against the cylinder walls will wear "micro" grooves in the rings that match up against corresponding ridges on the cylinder wall. If the rings rotated there would never be this ridge/groove result. Since you can see and sometimes feel the grooves and ridges, I can only assume the rotation of the ring is not happening. That is why cylinders get a crosshatch pattern during the honing process. The microgrooves go around the cylinder, not parallel to its major axis. |
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