Piston And Rings
- Clean piston
- Using a gasket scraper, remove the carbon from the piston top.
- Using a groove cleaning tool or broken ring, clean the piston ring grooves.
- Using solvent and a brush, thoroughly clean the piston.
NOTE: Do not use a wire brush. - The standard measurement of the piston outside diameter is taken 14 mm (0.5512 in.) from the bottom of the piston.
Standard diameter
95.96-95.99 mm (3.7779- 3.7791 in.)
- Calculate the difference between the cylinder bore diameter and the piston diameter.
Piston-to-cylinder clearance
0.03-0.05 mm (0.0012-0.0020 in.)
- Inspect the piston ring side clearance.
Using a feeler gauge, measure the clearance between new piston ring and the wall of the ring groove.
Piston ring side clearance
Standard
No.1: 0.03-0.07 mm (0.0012-0.0027 in.)
No.2: 0.03-0.07 mm (0.0012-0.0027 in.)
Oil ring: 0.06-0.15 mm (0.0024-0.0059 in.)
Limit
No.1: 0.1 mm (0.004 in.)
No.2: 0.1 mm (0.004 in.)
Oil ring: 0.2 mm (0.008 in.)
Courtesy of KIA MOTORS AMERICA, INC.
If the clearance is greater than maximum, replace the piston.
- Inspect piston ring end gap.
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 ring. If the gap is too large, recheck the cylinder bore diameter against the wear limits. Refer to CYLINDER BORE INNER DIAMETER REFERENCE . If the bore is over the service limit, the cylinder block must be replaced.
Piston ring end gap
Standard
No. 1: 0.17-0.32 mm (0.0067-0.0126 in.)
No. 2: 0.32-0.47m (0.0126-0.0185 in.)
Oil ring: 0.20-0.70 mm (0.0079-0.0275 in.)
Limit
No. 1: 0.6 mm (0.0236 in.)
No. 2: 0.7 mm (0.0275 in.)
Oil ring: 0.8 mm (0.0315 in.)