ring mfg's recommend 3-4 thousandth per inch of bore.
common practice is less.
you definatly want enough that they don't . collide
Anyone one try the I think they are call total seal? No gap. I think they are 2 or 3 thin rings to male up one standard ring.
They work great but the piston has to have the ring groove machined,the ring is actually a compression and an oil ring rail in the same groove.