It is not a bad idea next time you do a plenum pull to upgrade these things. Once the tar leaks out and usually makes a mess, there is a pushrod with a spring on it that helps this speed the process. The pushrod slams backwards each time the vtc dissengages. Believe it or not but there is not backing what so ever on the vtc. Once the tar is gone, the only thing from stopping the pushrod from coming out is the electrical post slightly bent to stop it. This electrical post where the wires are soldered on and is a very soft metal. The pushrod has two journals that run down the shaft. This allows for oil to flow pretty freely out the back may cause the crank case to have more of an atmosperic pressure then Positive Crankcase Ventilation (PCV). Basically, your Crankcase will be venting out the back of your motor through the VTC is what I am getting at.
