Cylinder Block

1. Check the cylinder block for scores, rust and corrosion. Also check for cracks or any other defects. Replace the block if defective.
2. Measure the cylinder bore with a cylinder gauge at the three levels indicated, in the directions A and B.

   Level 1: No.1 piston ring position at TDC

   Level 2: Center of cylinder

   Level 3: Bottom of cylinder

   Fig 1: Measuring Cylinder Bore

   Courtesy of HYUNDAI MOTOR CO.
3. 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. New oversize pistons and rings should be installed.

   Standard value 

   Cylinder bore: 86.7 mm (3.41 in.)

   Out-of-round and taper of cylinder bore:

   Max. 0.02 mm (0.0008 in.)

4. If a ridge exists at the top of the cylinder, cut it off with a ridge reamer.
5. Oversize pistons are available in two sizes.

   Piston service size and mark mm (in.) 

   0.25 (0.010) O. S: 0.25

   0.50 (0.020) O. S: 0.50

6. To rebore the cylinder bore to the oversize, maintain the specified clearance between the oversize piston and the bore and make sure that all used pistons are the same oversize. The standard measurement of the piston outside diameter is taken at a level of 15.5mm (0.61 in.) above the bottom of the piston skirt and across the thrust faces.

   Piston-to-cylinder clearance 

   0.01 ~ 0.03 mm (0.0004 ~ 0.0012 in.)

   Fig 2: Measuring Point On Piston Skirt

   Courtesy of HYUNDAI MOTOR CO.
7. Check for damage or cracks in the cylinders.
8. Check the top surface of the cylinder block for flatness. If the top surface exceeds the limit, grind to the minimum limit or replace.

Standard value 

Flatness of gasket surface: Max. 0.03 mm (0.0012 in.)

Service limit 

Flatness of gasket surface: 0.05 mm (0.0020 in.)

Fig 3: Checking Top Surface Of Cylinder Block

Courtesy of HYUNDAI MOTOR CO.