Abstract: An engine having a variable valve timing mechanism may include a camshaft having a cam formed thereon for moving an intake or exhaust valve, a variable rotation unit disposed on the same axis with the camshaft to rotate the camshaft to have a retard angle chamber and an advance angle chamber for controlling a retard angle and an advance angle of the camshaft, a variable valve bolt having a fastening portion for fastening the variable rotation unit to the camshaft, and an oil control valve for making selective supply of hydraulic oil to the retard angle chamber and the advance angle chamber, and a valve controller disposed on an outer side of the variable rotation unit for controlling the oil control valve in the variable valve bolt.

Abstract: An engine having a variable valve timing mechanism may include a camshaft having a cam formed thereon for moving an intake or exhaust valve, a variable rotation unit disposed on the same axis with the camshaft to rotate the camshaft to have a retard angle chamber and an advance angle chamber for controlling a retard angle and an advance angle of the camshaft, a variable valve bolt having a fastening portion for fastening the variable rotation unit to the camshaft, and an oil control valve for making selective supply of hydraulic oil to the retard angle chamber and the advance angle chamber, and a valve controller disposed on an outer side of the variable rotation unit for controlling the oil control valve in the variable valve bolt.

Abstract: An oil supply device includes a plurality of hollow cam shafts, cam shaft journals, and a shaft side path. The hollow cam shafts have through holes that pass in a longitudinal direction from interior to exterior thereof. The cam shaft journals are provided on every position at which the through holes are formed. Each of the cam shaft journals has a path connected with an associated through hole and is coupled with a cylinder head. The shaft side path is formed to supply oil into each hollow cam shaft after the oil sequentially passing from an oil pump through an associated cam shaft journal and an associated through hole.