The reciprocating engine comprises a rocker valve gear, pistons which are fastened to a connecting rod and connected by crankshaft journals to a crankshaft, a balancer, and a camshaft which is driven by the crankshaft and in turn actuates rockers, the mentioned elements being arranged in a crankcase having a cylinder head and cylinder head cover. The cylinder head is provided with integrally cast or screwed-on receivers serving for the attachment of the hollow camshaft without requiring separately fastened bearing blocks. Correspondingly, the cylinder-head comprises further integrally cast or screwed-on receivers which serve for the attachment of the hollow rockers without requiring separately fastened bearing blocks.