Ouch, sounds like someone blew a plug out at some point in that van's past and used a plug shim to get the new one in.  Usually just a temporary fix, but I had a friend who drove his for another 50k before addressing the replacement head.  Your options are:

a) install a new shim with the new plug (this may be difficult and prone to failure)
b) install a new aluminum head

Smarter heads than I may have other suggestions.

MT

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of Harry Hoffman
Sent: Tuesday, November 02, 2010 1:53 PM
To: vanagon@GERRY.VANAGON.COM
Subject: spark plug threads

Hi All,

So, I started to tune up my vanagon but replacing the spark plugs. I took the second plug out and out with the plug came the steel (?) thread that lined the spark plug hole.

I can still see threads in the hole but now the plug just drops in the hole.

What are my options? Pulling the head and getting it re-threaded?

Cheers,
Harry