A vehicle engine includes: a cylinder head; a cam housing fixed to a top of the cylinder head; a cam cap fixed to a top of the cam housing; a camshaft rotatably supported between the cam housing and the cam cap, the camshaft supporting a cam; a rocker arm configured to be pushed by the cam; and a valve configured to operate by being pushed by the rocker arm; and an oil pipe that is formed integrally with the cam cap. Lubricant oil is supplied through the oil pipe to a contact point between the cam and the rocker arm.