A remanufactured engine is assembled essentially the same way engines are for a new car. The major reusable components are machined, bored, welded , planed, and polished to the highest possible tolerances. Crankshaft, block, and head castings are subjected to precise checks to guarantee their integrity and fit. The remanufactured components are then assembled together with entirely new, factory fresh pistons, rings, bearings, timing components, gaskets, seals, bushings, lifters, oil pump, and more. The engine is then thoroughly tested before it is given to the customer.