Use a spatula to remove any remaining gasket material from the cylinder block, being careful not to damage the surface.
Remove the main bearing caps and take the bearings out of the cylinder block and caps. Please indicate which cylinder the bearing belongs to and the part from which it was removed (from the cover or cylinder block); put them separately from each other.
Using special Allen keys, unscrew and remove all threaded plugs from the cylinder block channels.
If the engine is heavily soiled, it should be taken to a car repair shop to be washed with a strong jet of steam or in a hot chamber. Almost all stores sell brushes for cleaning oil channels and holes. Rinse the internal passages with a stream of warm water until the water runs clear, then thoroughly dry the cylinder block and lubricate the treated surfaces with oil, which will protect them from corrosion. If possible, blow compressed air through the block and internal passages to speed up the drying process.
If the block is only slightly dirty, it is enough to wash it with a stiff brush and warm water with detergent. Take your time and do this job thoroughly. Regardless of the cleaning method, thoroughly clean the oil channels and holes, dry the block and lubricate the treated surfaces with oil.
The threaded holes in the cylinder block should be cleaned with a tap to ensure correct tightening torque readings during assembly. Cleaning with a tap will clean the threaded holes from dirt, traces of corrosion and sealant residue, and restore the threads. If possible, blow out the holes with compressed air to remove any remaining material after tapping. Thoroughly clean the threads of the cylinder head bolts and main bearing caps.
Information copied from the portal: Mazbook
Reinstall the main bearing caps and tighten the bolts finger tight.
Install new plugs into the cylinder block, having first lubricated them with high-temperature sealant. Make sure that the plugs are seated correctly and are not warped, otherwise leaks may occur. To install the plugs you will need a special tool. This operation can be performed with the same level of quality using a hammer and a mandrel whose diameter corresponds to the hole in the plug.
If the engine will not be assembled at this time, cover the cylinder block with a plastic cover to protect it from contamination.