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Old 12-08-2010, 04:51 PM
olddog olddog is offline
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Join Date: May 2006
Location: St. Louisville, Oh
Cobra Make, Engine: A&C 67 427 cobra SB
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Quote:
Originally Posted by Barry_R View Post
Rings rotate. Factual data is a dangerous thing. When I ran Speed-Pro we had lab data that proved it. Use radioactive pellets embedded in rings to see how fast on the dyno. Turned out to be around 10-12RPM, but completely at random - sometimes they reversed themselves.

Movement was just considered to be due to variations in bore finish and profile. A poor hone job can have deep grooves in one direction and shallow ones in the other - that'll cause the rings to spin rapidly in the grooves and they will wear out very quickly. Gaps lining up is usually bad bore profile - an irregularity in cylindrical shape.
Was the block honed by a precision machine?

10-12rpm at what condition? WOT high rpm?

Do they rotate at idle and normal driving conditions (say 2000 rpm 30 hp)?

Does the top and 2nd ring rotate the same direction and speed, thus the gaps always stay at a fixed angle from each other?

Do the oil rings rotate?

3 piece oil ring?
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