Self-repair of the engine can be performed in several ways. The decision to replace the cylinder block, piston/connecting rod assemblies and crankshaft depends on several factors, the main one being the condition of the cylinder block. Other considerations are price, availability of a machine shop, availability of spare parts, time to complete the job, and level of experience in doing mechanical work yourself.
Options include:
Separate parts - If a condition check has shown that the cylinder block and most of the engine components can be reused, then the most economical option may be to purchase separate parts. The crankshaft block and piston/connecting rod assemblies must be thoroughly inspected. Even if the block has minor wear, the cylinder surfaces must be honed.
Set with crankshaft - Kit (if available) consists of a ground crankshaft with new matching rebuilt main and connecting rod bearing shells.
Sometimes such a set includes remanufactured connecting rods and new pistons with rings (such a set is called "engine kit"). If the block is in good condition, and the crankshaft journals are worn or burred, then a crankshaft kit and other separate parts may be the most economical option.
Small set with block - The small set consists of a cylinder block with a crankshaft and pistons/connecting rods mounted on it. New bearings installed and all clearances properly set. Existing camshaft, valve components, cylinder heads and attachments can be fitted to the block with little or no shop machining required.
Complete set with block - "Full" or "big" kit includes small kit and oil pump, sump, cylinder head, cylinder head cover, camshaft, valve components, gears and chain (or belt) gas distribution drive mechanism. All components have new bearings, seals and gaskets. It remains only to attach the intake pipeline, exhaust manifold and attachments.
Consider carefully which option is best for you and consult your local machine shops, parts dealers and experienced engine rebuilders before purchasing or ordering new parts.