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Old 10-24-2012, 04:02 PM   #21
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Join Date: Mar 2005
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2005 Super Slow STi


Originally Posted by reid-o View Post
I would assume that, since the bore is now distorted, the ring will follow the shape of the bore, and so the gap will now be tapered with outer edge or inner edge having more or less gap depending on the amount of distortion.
.001 distortion x pi = .003" ring gap change.
.0015 distortion x pi = .0047" ring gap change.
.002" distortion x pi = .0063" ring gap change.

From JE's installation guide: "A diameter variance from one cylinder to the next changes the end gap of the rings
in that cylinder by a factor of pi (3.1416). For example, a cylinder .001 larger in diameter will increase the ring end gap by .001 x 3.1416 = .003,
rounding off, which could increase cylinder leakage in that cylinder and decrease performance"

From CP's installation guide: "RING GAP MEASURING
1. A torque plate should be installed on engine (if applicable)
and torqued to same specifications as machine shop.
2. Piston ring should be below and square to the deck.
3. Measure ring end gap with a feeler gauge."
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