How should a technician check the piston ring side clearance (clearance between the ring and its piston groove) during an engine inspection?

1. Fit the piston ring into its groove and insert a flat feeler gauge between the ring surface and the groove wall.
2. Measure the thickness of the ring with a micrometer and the groove width with a vernier caliper, then subtract the two values.
3. Place the ring into the cylinder bore and measure the space between the ends of the ring with a feeler gauge.
4. Measure the distance from the outer edge of the ring to the piston center axis using a depth gauge.