Very interesting article! It leads me to question Kohlers' ring end-gap specification of .010 - .020 inches for the K321 engine!
From the article: "End Gaps McKnight says the optimal end gap for a top compression ring is when you achieve the smallest gap without butting the ends of the ring together when the rings get hot. “A good starting point for the top compression ring is .0045? per inch of bore diameter for a naturally aspirated engine,"
The K-321 engine approximate piston diameter = 3.5 inches, 3.5X.0045= .016 inches end gap.
I gapped my rings at .011 -.012 on my recent rebuild job, Is this end gap too tight for an air cooled engine? Can't imagine a water cooled engine needing more end gap.
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