2000 SC 1.9 losing rocker arms !!!

I am working on a 2000 Sc with a 1.9 DOHC. my friend called me and said the car wouldn't start. The car cranked over and sounded like an engine with a broken timing chain/ belt. It spun over very fast, but then started and ran, although very poorly. It also had alot of noise coming from under the valve cover. Upon removal of the valve cover, I found 5 rocker arms completely off from the rear cam. The front cam is fine. Unfortunately one valve was bent, so I know that I have a fun little project ahead of me. My question is the cause of all of this. One guy told me that the oil is too thick and since the back cam is the last thing to get oil, that maybe the lifters didn't get pumped up and let the rockers slip out. ( temps are in the single digits here and it has 10 w 40) I am thinking it's out of time. I don't have the front cover off yet. But could just one cam get out of time ? And would it still run? Any help would be appriciated.

wow, um there are many variables. but one thing, what do you mean by rocker arms? dohc engines use direct cam to hydraulic lifter to operate valves.

On this particular engine, the lifter sets in the head across from the valve and it has a roller rocker that sits one end on the lifter and one end on the valve. The cam then rides against the roller, pushing the valve down. These are what came out of place. Last night, I got the front cover off, the chain is tight, but I haven't had time to make sure that everything is in time. I know the chain has to come off to get the head off, but I want to find the cause as I go.

ok i stand corrected. the newer dohc heads got roller rockers, while older heads got the cam to lifter operation. then i also understand that those heads are junk. see the engine could have been ruined under high rpms. say they go into high rpms and a valve to two float and the piston hits it and knocks everything else loose. ive been around many saturn owners that modify their cars and not a single one of them likes the newer head from like 99 or 00 on. they are a poor design. i couldnt say for sure what happened to the engine since i have heard of this case before.