Measuring Cylinder Bore Out-of-Round
Courtesy of GENERAL MOTORS COMPANY
- Measure both the thrust and non-thrust cylinder diameter at 10 mm (0.394 in) below the deck surface (1). Record your measurements.
- Calculate the difference between the 2 measurements. The result will indicate out-of-round at the upper end of the cylinder.
- Measure both the thrust and non-thrust cylinder diameter at 125 mm (4.921 in) below the deck surface (2). Record your measurements.
- Calculate the difference between the 2 measurements. The result will indicate out-of-round at the lower end of the cylinder.
- Compare your results with the Engine Mechanical Specifications (LTG)
, Engine Mechanical Specifications (LKW)
, . If the cylinders exceed these specifications, the cylinder block may be oversized to 0.25 mm (0.010 in). There is only one size of oversized pistons and rings available for service. Refer to Cylinder Boring and Honing .