Nissan Variable Cam Timing (commonly known as N-VCT, VCT, NVCS or CVTC) is an automobile variable valve timing technology developed by Nissan. N-VCT was first introduced in 1987 on the VG30DE and VG20DET engine.
N-VCT varies valve timing by rotating the affected camshaft(s) relative to the sprocket; valve lift and duration are not altered. This rotation is achieved when an electric solenoid, controlled by the car's ECU, allows pressurized engine oil to flow into and through the cam and into a slave mechanism, axially advancing cam timing relative to the sprocket. Some Nissan engines only have N-VCT on the inlet cam (such as the GA16DE or RB25DE/DET) while others have it on both the inlet and exhaust cams.