Hey all, I have a 2011 Acadia 2wd that I had to replace the cam phasers on. I've been reading all over the internet how the 3.6L is not a an interference motor but severe engine damage can occur if a timing chain breaks. Now then, I got the phasers replaced and I was going from stage 1 timing to stage 2 and I got the crank turned about 1/2 to 3/4 of the way to the next dot and the engine feels like its hitting something. I stopped rotating and it looks like cyl 5 has its valves open. Are these interference motors or not? And how can I start the timing over if need be without destroying the engine?

If severe damage occurs due to timing chain break it'* an interference engine.You need to get it in time close enough or it will hit.

To do this job, I'd mark everything then return it before putting the chains back on.

You've gone beyond this step, so it might be a good idea to scope each cylinder and see what is happening inside, probably starting at #5.