[AT] Stripped threads in alum head

[charles bridges]

  I am working on an overhead cam engine and one of the bolts that holds the 
cam shaft cap on is stripped.  It is an alum head, and I am trying to fix it 
without pulling the head.  We are looking at 150 bucks worth of gaskets and 
a lot of work to pull the heads.

The are two steel sleeves imbedded in the top of the head where the cam 
shaft cap bolts go.  Looks like they are about a 1/4" down in the head and 
protude about a 1/4" above, which lets them go about that far up in the 
camshaft cap.  The drill bit or tap for the helicoil will not go through the 
steel sleeve.  How do you get them out to drill and tap the hole out.

The camshaft caps take 8mm bolts and of course a 8mm tap will go through the 
sleeve.  I need to drill the hole bigger in order to tap it for a helicoil.



Any suggestions will be appreciated.

Charles