Integrated combined casting method for diesel engine body sand core

According to the diesel engine body sand core integration and combination casting method, the integral core bar with the deformation prevention function is designed, the oil and water channel double-pipe integral sand core with the long and thin oil channels and the long and thin water channels is integrally manufactured at a time, size deviation caused by independent casting of two holes is avoided, internal skin seams formed by casting of a plurality of sand cores are avoided, and product quality is improved. Leakage and oil-water pollution caused by deformation, bending, gaps and the like of the cast-in steel pipe are avoided; the surface of the oil and water channel double-pipe integral sand core is coated with different coatings in a combined mode, so that the cleanliness of the inner wall of a long and thin high-temperature cavity channel pipeline is improved, and the production efficiency in the cleaning stage is improved; the internal size and the surface quality of the air cavity are improved by manu