I am rebuilding my 2004 liberty 3.7L. I installed new pistons had heads cleaned and inspected. valves and seats lapped they machined heads but went to 4.580-4.584. (Low to minimum). After installing heads and new timing set I tried to rotate crankshaft manually to verify smooth operation an found that I could only go about 45 degrees before intake valve contacted #1 piston. Then rotated back counter clockwise and intake valve is contacting #2 piston. I have set all timing marks EXACTLY AS MANUAL INSTRUCTS, right and left cams with v6 marks at12:00, idler gear mark at 12:00 and crankshaft gear mark at 6:00. All marks on new chains are correctly located. WHAT'S GOING ON HERE??? I am baffled! Any thoughts?