timing belt broke ,no loud noises . on 2004 Nissan Frontier

How can I tell which lobes (valve) is open/closed with out taking off the valve covers?.I am trying to align my cam sprocket.THANKS A BUNCH

Asked by for the 2004 Nissan Frontier
I have never seen the older engine (VG30E) not do serious damage even braking the valve guides in the head when the t/belt breaks. The VG33E is an interference engine as well.
Take out all the spark plugs. Remove the upper timing cover. There are punch marks on the rear timing cover the passenger side sprocket has a corresponding mark at approximately 11:00, the driver's side sprocket has alignment marks at approximately at 2:00 o'clock, the crank pulley should be at TDC. You will have to delicately move the crankshaft pulley bolt getting the pistons down the bore so as not to make contact with valves.
Your engine has hydraulic lifters. Its going to be difficult on a V6 to move the pistons, and both camshafts and not at some stage make piston to valve contact.