PG Turbos?? Re: <VV> Re: TURBO BENT VANES

[D. Barry Ellison]

Your description of head gasket area is EXACTLY what I found my most recent noises to be.  We (me and my motor head brother) thought it was a wrist pin.  So, being the 3rd tear down in about a year, I put it aside until 2 weeks ago.
 
Turns out, it wasn't the wrist pin but there was a tiny valve seat or piston ring piece embedded in the head from one of the two recent failures (dropped valve 1st time and broken rings/piston the 2nd).  As it was pounded in to the head, the area around it was raised, and piston head contact.  There were 30 pieces of valve seat in the chamber which I picked them all out the 1st time, so oops - I guess I missed one.
 
All the times I pull these heads apart, the head gasket surface has been compromised.  The head gasket get compressed into the head, creating the exact 'fence' you mention.  I smooth it up each time - now, I'm down to just about no gasket surface whatsoever, increasing compression and likelyhood for pinging.  :(  NOT what I wanted.
 
Now I'm wondering if that's a rare thing or not?  Do I just have crappy, overworked and overheated heads?
 
But the good news is, it's almost back together - maybe this weekend if I avoid Lowe's Motor Speedway.Barry in SC2 lates, 2 earlies> cause the extruded metal to actually contact the piston crown, > causing what sounded a lot like a wrist pin knock when it was > actually the piston hitting this extruded bead of aluminum.> > The gasket had actually sunk down into the metal which was supposed > to be the flat and thus the highest part of the chamber, only now > this "rolled up" bead of aluminum was now sticking up like a fence