After putting about 2 miles on my re-built Z6 motor, the car shut off. I saw that the cam gear was sheared off the camshaft.

I pulled the V/c and noticed the cam was damaged and so were the caps and the head itself.



Has anyone seen such a thing before? There was oil in the head, and it was torqued to specs. Any ideas why this happened?

 

Never seen it happen before but I guess it isnt impossible. Not sure how those engines are internally but is it possible you mixed up caps for it? Is it an OEM cam?

 

Some stupid possibilities:
-Mixed up the caps
-Didn't use assembly lube
-Didn't prime the oil pump before starting


But I think it's more of a clearance issue. Was it hard to manually turn the cam with a ratchet once the caps were torqued down?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rdssk8rcs1 &raquo;</TD></TR><TR><TD CLASS="quote">Never seen it happen before but I guess it isnt impossible. Not sure how those engines are internally but is it possible you mixed up caps for it? Is it an OEM cam?</TD></TR></TABLE>

OEM cam, its possible the caps were mixed up.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Legion &raquo;</TD></TR><TR><TD CLASS="quote">Some stupid possibilities:
-Mixed up the caps
-Didn't use assembly lube
-Didn't prime the oil pump before starting


But I think it's more of a clearance issue. Was it hard to manually turn the cam with a ratchet once the caps were torqued down?</TD></TR></TABLE>

I used assembly lube, and primed the engine by cranking it with the dizzy unplugged. Everything was torqued to Helm manual and it seemed to turn fine.
Upon further inspection the other journals look scored also. I should have plastigauged it.
Thanks for the replies, I appreciate it very much.

 

looks like a lube/improper cap situation to me.

 

I bought the head used, and I had the machine shop check to see if it needed to be
milled. I did not give him the rocker assy with the caps. It is possible that the caps were off of a different head. I learned the hard way that
the caps are Not interchangable.

 

Bearing clearances could have been extremely tight, not letting oil in.

or

You mixed up the caps,which have numbers on them to show where they belong. Doing that, probably blocked the oil passage hole to the bearing that seized.