2001 Cadillac Catera Timing Cams

I personally have never set the cam timing freehand. The dealer has a special tool kit for performing it, that includes some cam locking tools and a crank locking tool as well. I know with the tensioner and idler adjustments, a considerable amount of variation in settings can be achieved, all of which can have varying effects. You can have one, or the other bank of cams off, or both banks can be off, and you use the idler adjustments to dial them in. You do use the marks(1, 2, 3, 4), and the crank is at 6. There is a depression in the oil pump cover that aligns with the crank mark. A new belt also has marks that align with the sprocket marks, at least the GM belt does.

If the crank sprocket mark is at 6, and the 1-2-3, and 4 marks on the cam sprocket are up, and from left to right(looking at engine from front), I believe it is TDC. My question is, did it lose time? If so, you have bent valves. You can even bend valves in this engine by hand, if rotated out of sync.