4 The next step is preparing the cylinders. With some blocks, a cylinder hone can make sure the cylinders are straight and the cylinder finish is conducive for ring seal. However, if the cylinders have a lot of taper, gouges, and so on, the block will need to be bored. this provides a rough cylinder finish (usually within 0.005- to 0.010-inch of the desired finish bore size). Before boring, it’s best to check the current bore size to make sure that the block can be reused. a thin cylinder wall can cause block integrity issues.