RE: [alfa] Grinding valve shims vs valves

["Jeff Greenfield" <alfaguy@xxxxxxxxxxxx>]

With regards to grinding the ends of the valve stems ...

This is common practice during a valve job if the old valves are re-used.
When the valve faces and seats are ground the valve moves further up into
the head towards the camshaft. If whoever is doing this, is not familiar
with Alfas and gets a little too enthusiastic, or this is the second or
third valve job on the head, then you won't have shims thin enough to be
able adjust the valves to spec.

In order to avoid this problem, the ends of the valve stems are 'tipped' as
it is called. This should not provide any problems with the valve keepers
interfering with the shims provided it (as everything else should be) is
done in moderation. If too much material is removed here, then yes, the
keepers can and will interfere with the shims and the results will be
catastrophic.

In order to help avoid these problems, I prefer to use new valves when
having a head done over, but they still might need to be tipped depending on
the condition of the valve seats.

HTH,

Jeff

-----Original Message-----
From: owner-alfa@domain.elided [mailto:owner-alfa@domain.elided] On Behalf Of
Kevin Trent
Sent: Sunday, January 18, 2004 7:48 PM
To: alfa@domain.elided
Subject: [alfa] Grinding valve shims vs valves

At 08:10 PM 1/18/04 +0000, you wrote:

>"Ward, First of all, the shims were used, not new. The shims were
>turned down on a lathe. How much do you have to take off? If its a
>significant amount I would take it off the valve. They are through
>hardened (consistanty hard throughout) and not case hardened (just
>the very surface). Peter."

I'm not an expert, but it was my understanding you DO NOT want to take any
material off the valve stem, because it can lead to insufficient clearance
between the shim and the valve keepers, and can lead to catastrophic
results if the keepers release the valve.

Anyone know for sure?

//kct, Powell TN
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