400 to 451 stroker questions

The thinner ring simply requires less radial tension to do it's job, so less friction.

Obviously, better , more durable,ring material makes this possible.


Radial tension isn’t much of a friction saver. As the piston is coming up the bore, gas pressure forces the ring into the bore. The thicker face has the same pressure behind it and it causes more drag.

A thinner ring will out seal a thicker ring every time.