Why does compression in cylinders grow?
By restoring the cylinders geometry, compression grows by 10 to 20 % as early as in the first 500 to 1,000 km of running. We witnessed cases when the compression increased from 4 – 6 atmospheres to 10 – 12 atmospheres. Usually, low compression values are caused by mechanical damage (piston burnout, valves, etc.), rather than by natural wear.