The invention relates to a composite, a crankcase, a reciprocating internal combustion engine, and a method for producing a reciprocating internal combustion engine. A problem faced in the production of engine blocks is that requirements concerning component cleanliness and residual soiling standards have recently been greatly increased. Therefore, the problem addressed by this invention is that of simplifying engine block cleaning after casting, and allowing current and future residual soiling standards to be adhered to, while providing a solution to the challenges of current and future high-powered engines specifically for the load regions, namely the head plate and the cylinder pipe, and providing potential for locally improving properties in the crankcase in the additional load regions, namely the head and crankshaft bearing screw connection. This problem is solved inter alia by virtue of a composite that consists of at least two cylinders and one planar cylinder head support surface that connects these, wherein said composite consisting of at least two cylinders and the planar cylinder head support surface that connects these is made as a single piece, said planar cylinder head support surface having a recess for each cylinder, and the composite being able to be inserted into or placed onto a crankcase of a reciprocating internal combustion engine; and is solved in that at least one coolant guide is arranged between said cylinders.