Timing Belt Swap - Rotating Cams and Cranks Independently?

About to swap in a new timing belt and I’m concerned about spinning the cams or crank the wrong way or independently when the belt isn’t connected. For example, with the belt off, what happens if I spin the crank shaft but not the cams? If one of them spin because I bump into them, can I just turn it clockwise until I get it back to top dead center?

Additionally, when trying to remove the crank shaft bolt with an impact wrench, what might happen if the crank shaft spins counter clockwise due to the bolt not coming free?

 

Loosen the crank bolt before removing the belt.

The 3.4 is generally considered to be non-interference but it's still not recommended to rotate the cam and crank independently.

Once the balancer, timing covers, and fan idler are off the belt can be easily removed without disturbing the timing.

 

The 3.4-liter engine is indeed a non-interference engine meaning that the valves and pistons never touch each other.

You can remove the belt and then rotate the crankshaft, and both camshafts, until the cows come home without problems. Same for the camshafts. Just remember to align the notch on the crankshaft with the mark on the engine, and then rotate each camshaft until their marks align with the marks, then install the timing belt. (When you install the timing belt, don't pay any attention to whatever arrows might be stamped on the new timing belt. They don't mean a thing. I have not the foggiest idea why they are there in the first place.) When the belt is on and tensioned, the marks on the crankshaft and both camshafts should still be aligned.

As a final check, turn the crankshaft two complete turns clockwise (after you tension it) and verify that all marks are still are aligned correctly. They won't be perfectly exactly 100% fully aligned due to a take-up of space between the belt teeth and the gears and also to very slight stretching of the belt.

Be sure to watch Timmy the Toolman's video before and during the work.