Short block

This is a 3S-GTE shortblock on an engine stand waiting to be cleaned.

The same engine after cleaning. Carbon deposits can be removed with a wire brush and the surface is then polished with a very fine sandpaper. Many times this kind of work is done by a machine shop as part of a more involved engine rebuild. Rebuilding an engine helps restore power and economy and/or improve or increase performance

Short block is an automotive term describing an engine sub-assembly.

A short block is the portion of the cylinder block below the head gasket but above the oil pan. An in-block cam engine will also include the camshaft and timing gear and any balance shafts. The overhead cam style of engine will not include the aforementioned parts on the shortblock.

A shortblock is usually purchased as a quicker way to rebuild an engine, rather than do all the work separately. This is more convenient and possibly more cost effective. Short blocks purchased in this way may also have undergone performance improving engine work. Machine shop work can increase performance by boring the engine (increasing the diameter of the cylinders (which increases internal volume), balancing the rotating assemblies (such as the crankshaft), installing a higher performance camshaft, etc. When engines are bored they require larger pistons and new piston rings. This kind of work can be done by amateurs (sometimes referred to as "shade tree mechanics," or can be done by professional machine shops or engine rebuilders.

A short block is considered destroyed when it either warps or cracks, often due to overheating.

See also

• Long block