Short Blocks and Long Blocks


The heart of every engine is the combustion chamber and is composed by the inner part of the cylinder and by the top side of a piston. On the top of it, the combustion chamber is closed by the cylinder head (where the valves are housed) and is fixed to the cylinder through screws. The piston is free to move inside the cylinder by performing a rectilinear reciprocating motion. Through a tubular pin the piston is connected to the piston rod, a rigid and robust shaft, which is bounded to the crankshaft. The crankshaft is a crank and is equipped with main and pin bearings. The so constituted system is bound to the base by some supports, which are decomposable in order to facilitate the engine assembly. The crankcase constitutes the main body of the engine in which the cylinders are inserted and, consequently, the pistons. The term short block refers to the crankcase with the crankshaft, the connecting rods, the pistons, the piston rings and the bearings. The term long block is used when the short block engine is equipped with cylinder head, intake and exhaust valves, springs with caps and engine gaskets. Short blocks and long blocks have some advantages compared to the overhaul one. The first benefit is in time saving: no disassembly of the old engine; no identification or purchase of spare parts and therefore no risk of error.  You’ll also have a quality product: use of quality parts, technically correct assembly, warranty, long-term use. The last advantage is a save in money: low price compared to the spare parts; reduced use of manpower; alternative employment of the old engine to recover or revise some parts.