Cylinder Block

Check the engine block for scores, rust and corrosion. Also check for cracks or any other defects. Replace the block if defective.
Using a straight edge and feeler gauge, check the top surface of the block for warpage. Make sure that the surface is free from gasket chips or other foreign material.
1. Standard: 0.03 mm (0.0012 in.) or less
2. Limit: 0.1 mm (0.0039 in.) or less
Fig 1: Checking Cylinder Block Flatness
Courtesy of HYUNDAI MOTOR CO.
Measure the cylinder bore with a cylinder gauge at three levels in the direction of A and B. If the cylinder bores show more than the specified out-of round or taper, or if the cylinder walls are badly scuffed or scored, the cylinder block should be rebored and honed. Now oversize pistons and rings must be fitted. The value of measuring points are as shown.
1. Cylinder I.D: 82 mm (3.228 in.)
2. Cylinder I.D taper: 0.01 mm (0.0004 in.) or less
Fig 2: Measuring Cylinder Bore
Courtesy of HYUNDAI MOTOR CO.
If a cylinder ridge exists, cut away with a ridge reamer.
Oversize pistons are available in four sizes.
Piston service size and mark mm (in.)
1. 0.25 (0.010) O.S.: 0.25
2. 0.50 (0.020) O.S.: 0.50
3. 0.75 (0.030) O.S.: 0.75
4. 1.00 (0.039) O.S.: 1.00
When boring the cylinder bore to the oversize, maintain the specified clearance between the oversize piston and the bore, and make sure that all pistons used are the same oversize.
The standard measurement of the piston outside diameter is taken 47 mm (1.85 in.) from the top land of the piston.
Piston-to-cylinder clearance (To set limits to new parts)

0.02-0.04 mm (0.0008-0.0016 in.)
For used parts, it is acceptable if the maximum clearance is 0.085mm or less.