Abstract The lubricating oil distribution significantly impacts the lubrication and cooling of the connecting rod small end bearing during the splash lubrication. This study investigates the oil supply for the small end bearing with splash lubrication utilizing the smoothed-particle hydrodynamics. The oil distribution and inlet volume are analyzed under various engine speeds. The results reveal that the oil moves close to the piston surface and hardly enters the oil bores, resulting in oil wastage. The oil entering the bores might be thrown out due to the inertia, causing the oil inlet volume to fluctuate. With increasing engine speeds, the total oil inlet volume under the quasi-steady-state gradually diminishes, exacerbating the lubrication conditions.