4.22. Check of a condition of the block of the engine

Previously the block has to be carefully cleared (see Cleaning of the block of the engine).


  1. Make external survey of the block regarding identification of traces of corrosion, cracks and other damages. Check a condition of a carving of bolted openings. It will also be reasonable to make testing of the block for existence of the hidden cracks in the conditions of a workshop of car service with use of the special diagnostic equipment. In case of detection of defects the block is subject to recovery repair or replacement.
  2. Check a condition of mirrors of cylinders.
  3. Estimate sizes taking place of conicity and ovality of cylinders:
    • Measure diameter of each of cylinders in top (directly under limit of step wear), the central and lower sections in the plane of a parallel axis of a bent shaft;
    • Now measure diameters at the same three levels, but in the plane, a perpendicular axis of the block;
    • The size of conicity of the cylinder is determined by a difference between results of measurements in the top and lower sections. Ovality is called the difference of diameters in a parallel and perpendicular axis of a bent shaft in each of the planes;
  1. Working in the described manner, serially check all cylinders.
  1. Standard diameters of cylinders can have insignificant dispersion for the purpose of which compensation pistons of several standard dimensional groups are issued — number of group is beaten out on the surface of the block near each cylinder, and also on the piston bottom, behind a forward tag.
  1. At installation of pistons of the standard size track compliance of their dimensional groups to dimensional groups of the corresponding cylinders. At installation of conrod assemblies pistons have to are developed by forward tags on the bottoms on the engine forward.
  1. At detection of noticeable defects or a deviation of results of measurements from standard requirements, the block of cylinders is subject to recovery machining in the conditions of a workshop of car service. If in the course of recovery repair boring of cylinders was made, the engine has to be completed with new pistons corresponding repair (with excess) the size.
  2. If the condition of mirrors of cylinders during performance of check is found satisfactory at simultaneous observance of standard requirements to a form of cylinders and to gaps of landing of pistons in them (see Check of a condition of components of conrod and piston group), need for a pro-point of cylinders disappears. Will only be to execute a honingovaniye of their mirrors enough (see Honingovaniye of mirrors of cylinders).
  1. Check planeness of the surface of the block interfaced to a head (measurement has to be performed in three directions: on an axis of the block and two of its diagonals. Compare result of measurements to requirements of Specifications, in case of need give the block to a pro-point.