Chipped exhaust valve, what to do?

[Shane]

After recently removing my cylinder head to replace the injector
buckets properly and to clean out the debris left after they crumbled
to pieces I noticed that the #3 cylinder exhaust valve is chipped
quite badly. We recently just rebuilt this engine and the head was
fine about 700 kms ago when we first put it together. I'm wondering
if there was any specific reason for this happening and if I should
replace just that one valve or just do all of them? The head was
ported and compression ratio was increased by milling the head and
the timing was always set correctly so that the valves were not
knocking. I'm just wondering if the valve chipped due to age or was
it caused by something else? Thanks for the help..

Shane
84' GTI

[Anton382]

Although it looks like a chip it sounds like its "Burnt", this can happen due
to many reasons, mixture too lean, piece of some type of crap getting between
the valve and the seat which actually causes a blow torch effect on the valve,
You see this quite regularly on air cooled engines where the temp is quite
high at times. If the others look O-K there should be no reason why you
couldn't just replace that valve. You should however inspect the seat
carefully, many times when a valve is burned or damaged it also takes the seat
with it. Also whoever replaces the valve shoul grind that seat or at a minimum
"Lap" it in with the new valve to insure a good seal. With only 700 kms on the
last valve job the rest of them should be fine. I think this is just a freak
thing on that one cylinder. I would take it back to whoever did it in the first
place, it sounds like you invested a lot of money in it, they shoul at least
take care of this one valve for you.

Good Luck,

Butch
88 Cabriolet (Daughters)
VW Manx Dune Buggy

[ViperWank]

Was the valve dropped prior to install and the heat cause it to come apart the
rest of the way? What is the valves composition?

[art clemens]

Solid lifter head right? Valve clearance got too far out.

[Bob Roberts]

If the valve was ground it can change the tempering of the metal. They are
supposed to be hand lapped only. This could make them brittle.

Or not.

Bob

"Shane" <be...@yesic.com> wrote in message
news:a2t7sscs7fihkrqs7...@4ax.com...