At 08:49 PM 1/5/99 -0600, Joshua Van Tol wrote:

>Another mode of failure for valves, particularly exhaust valves is burning.
>A valve burns when it doesn't spend enough time on the seat, or just
>because of long wear. What happens is a pie shaped piece of metal gets
>eroded from the edge of the valve. Also, with high milage, the valve guides
>can wear out and cause all sorts of valve wear problems because the valves
>don't always land in the right spot.

And if it's number three cylinder, another likely problem (especially for
air-cooled automatics) is that the engine has run hot and cracked the head,
to the point where the valve seat has come loose and jammed open the valve.
 You can check this easily. Yank the #3 plug wire.  If there is no change
in idle speed,  listen to the exhaust.  You'll get an odd 'chuff' every
time the piston in the bad cylinder comes up on compression.  Turn off the
engine, yank the distributor cap,  and turn the engine by hand.  When the
rotor comes up to the #3 position, the engine will suddenly get easier to
turn.  This just happened to me.  I confirmed it with a compression test.
As I haven't got the time to fix it myself, it's in the repair shop, where
my bill will be anything from $1,000 to $3,500.  Happy New Year!