camshaft sprocket just won't go on!

[tjn]

I am replacing the head on my 1990 535i and everything has been going well (thanks to the bentley and this forum)! Unfortunately, I am at a dead-still. After putting the head back on and tightening the head bolts (once) I am supposed to put the camshaft sprocket and chain on its guide... the problem is- no matter how hard I try- it will not go on!! I have tried everything I can think of, and nothing is making it fit right and flush (if the dowel is located right on at the bottom- the top will nut fit into place). I have tried to get as much chain slack as I can- but its minimal enough that I can't work it much. Can anyone offer suggestions on what to do? I am really hoping to get my car up and running again by the end of this weekend.
Thanks!
tim

[Martin in Bellevue]

The chain tensioner is out, right?

I rotated the cam just slightly forward to get the chain & sprocket to the cam.

[tjn]

Yeah... the tensioner is out, and I've already tried playing with rotation of sprocket and chain to no avail, but I will try moving the cam a bit to see if it helps.
Wish me the best... I'll take another try at it tommorow morning.
thanks,
Tim

[Dave535Phoenix]

I am replacing the head on my 1990 535i and everything has been going well (thanks to the bentley and this forum)! Unfortunately, I am at a dead-still. After putting the head back on and tightening the head bolts (once) I am supposed to put the camshaft sprocket and chain on its guide... the problem is- no matter how hard I try- it will not go on!! I have tried everything I can think of, and nothing is making it fit right and flush (if the dowel is located right on at the bottom- the top will nut fit into place). I have tried to get as much chain slack as I can- but its minimal enough that I can't work it much. Can anyone offer suggestions on what to do? I am really hoping to get my car up and running again by the end of this weekend.
Thanks!
tim

I know this won't help tjn 3 months later, but just in case someone does a search.

I had the same issue when installing my head; there was just not quite enough slack in the cam chain to allow the sprocket to be installed. One bolt and the positioning dowel would line up, but not the other three holes.

After about 45 minutes I finally solved the issue. I installed the one mounting bolt that would thread in, then got a smallish screwdriver that would fit through a non-aligned mounting hole. By gently prying around, I was able to get just enough slack to let that bolt thread in. I think just getting the second hole to line up was enough. If not, lather, rinse, repeat.

The chain was still very tight on the sprocket. Working the tensioner up and down a bit found the missing slack. Once the slack was back, the sprocket could be removed-replaced without any drama.

Theorizing now, I think the chain wasn't fully seated on the crankshaft sprocket caused by my hand-rotating of the engine opposite of it's normal roation (oops). That would account for the slack being off, and how easily the chain was skipping on the crankshaft sprocket while I tried to get the timing right.

Dave

[632 Regal]

did you try to rotate the crank a little to give you clack in the direction needed?