Piston And Piston Rings

1. Using a gasket scraper, remove the carbon from the piston top.
2. Using a groove cleaning tool or broken ring, clean the piston ring grooves.
3. Using solvent and a brush, thoroughly clean the piston.
   NOTE: Do not use a wire brush.

Standard diameter: 81.97-82.00 mm (3.2272-3.228 in)

Fig 1: Measuring Piston Diameter

Courtesy of KIA MOTORS AMERICA, INC.

Piston-to-cylinder clearance: 0.02-0.04 mm (0.0008-0.0016 in)

1. Piston ring side clearance:
2. No.1: 0.04-0.08 mm (0.0016-0.0031 in)
3. No. 2: 0.03-0.07 mm (0.0012-0.0028 in)
4. Oil ring: 0.06-0.15 mm (0.0024-0.0059 in)

1. Limit:
2. No.1: 0.1 mm (0.0039 in)
3. No.2: 0.1 mm (0.0039 in)
4. Oil ring: 0.2 mm (0.0079 in)

Fig 2: Measuring Piston Ring Side Clearance

Courtesy of KIA MOTORS AMERICA, INC.

If the clearance is greater than maximum, replace the piston.

To measure the piston ring end gap, insert a piston ring into the cylinder bore. Position the ring at right angles to the cylinder wall by gently pressing it down with a piston. Measure the gap with a feeler gauge. If the gap exceeds the service limit, replace the piston rings. If the gap is too large, recheck the cylinder bore inner diameter. If the bore is over the service limit, the cylinder block must be rebored. See CYLINDER BORE .

1. Piston ring end gap standard:
2. No.1: 0.23-0.38 mm (0.0091-0.0150 in)
3. No.2: 0.33-0.48 mm (0.0130-0.0189 in)
4. Oil ring: 0.20-0.60 mm (0.0079-0.0236 in)

1. Limit:
2. No.1, 2, oil ring: 1.0 mm (0.039 in)

Fig 3: Measuring Piston Ring End Gap

Courtesy of KIA MOTORS AMERICA, INC.