Turning cam with head off?

[Guest Anonymous]

I just got my head back from the machine shop after $800 of work and I need to set the valve lash now. How do I turn the cam with the head off??? I can't turn the gear by hand, I tried threading 2 long 10mm bolts into 2 cam gear bolt holes and turning it with a bar between the two, but I just bent a bolt.

I'm new to BMWs, I've always worked on h2o VWs, and I'm totally amazed at how hard it is to turn the damn camshaft in the head!!

Any ideas? I want to get the head at #1 TDC before I throw it on the block so I can have everything roughly lined up.

Kevin Fry

71 2002

71 project 2002

81 Scirocco turbo, 83 Rabbit GTI

[Guest Anonymous]

well i just had exactly the same problem and had no real difficulty turning the cam with two bolts and a screw driver between them... used the actual cam sprocket bolts so they werent particularly long...

by the way i think those have a 10mm head on a 6mm thread.. keep trying.. also, maybe make sure you are turning in the direction of operation (ie. clockwise)

cheers

ozgeorge

[Guest Anonymous]

First, be careful not to let the assembled head sit flat on its bottom surface, as there will be at least one valve head protruding below. Find some wood pieces to prop it up, or turn it on its side to prevent bending a valve.

You should set all the eccentrics to provide max valve lash before attempting to turn the cam again. If the lash is too tight anywhere, it could help bind things up depending on the cam lift, spring type & their installed height. At least, you want to insure there is no excess valve spring tension inhibiting the rotation. On the rockers that are not currently depressing a valve, can you confirm they are free on the shaft?

Did you assemble the head yourself, or the shop?

You want to know that there is adequate lube on the journals, lobes, rocker bushes and even a light film on the valve stems/guide ID. If this is unknown, at least dribble some engine oil over the parts you can access.

If the head was warped before, the cam journals could have some mis-alignment. During assembly, it's a good idea to check how free the cam turns without the rockers. If a warped head is machined flat on the bottom, the cam bore & rocker shaft bore alignments are still crooked after the bottom is made flat. In fact, you lose some of the straightening that would have occurred from the head bolt clamping to the block. Uusally, this shaft bore alignment just makes it very difficult to remove/install rocker shafts. The cam generally has much more installed clearance.

So back to turning your cam & your desire to adjust lash. Earlier, I had suggested setting the eccentrics to max lash. Provided you are eventually able to turn the cam, leave the lash full-loose untill the head is installed. There is no reason to set the lash with the head off the block. If you did it, you'd still have to repeat it again after the head was installed, 'cuz it will change.

[Guest Anonymous]

I've never had a problem turning the cam with the head using the 2 bolts as you describe. Did you check cam rotation before installing the rockers? If it wouldn't turn easily you have a problem. I assume you used lots of assembly grease on everything (cam bearings, rocker shafts, inside of rockers, top of valves where the eccentrics rub, etc)