The engine will be completely stripped down and washed before being inspected to see what parts are within tolerance. After inspection everything gets put into a cold acid bath so all oil and water ways are clean and free from debris, especially if the engine is badly damaged due to something like an oil pump failure.
After cleaning the block is rebored/honed and the crankshaft reground/polished, with new pistons and bearings being ordered to suit. The cylinder head is pressure tested, skimmed with valves faces and valve seats re-cut.
It is then all re-assembled using new gaskets, oil seals and oil pump. All engines come with a new timing belt or timing chain kit fitted. Upon completion is sprayed to make it look as good as new again!