where can i find free diagrams for a nissan twin cam 16 valve engines and transmishion?

Answer 1

http://autorepair.about.com/od/servicemanuals/Service_Manuals.htm

There are no free diagrams.

Answer 2

The number of valves really doesn't reflect the number of pistons. Most cars have 2 or 4 valves per cylinder(although I've seen one with 3 valves per cylinder). My Miata has 4 (16 total)valves per cylinder and 2 camshafts, but is an in line 4 cylinder. My old Jeep has 6 cylinders, one camshaft, but only 12 valves.....Confused? Higher number of valves is just a way to get more fuel into a cylinder and more exhaust out. Some V8's have up to 32 valves.