[alfa] RE: alfa-digest V10 #12

["Les Singh" <Les.Singh@xxxxxxxxx>]

Michael

Grinding the very top of valve stems is done by engine reconditioners to
square them off after the original profile has been lost because of the
punding and rubbing by rockers in a pushrod engine. There is no other
reason why valve stems should be ground and doing it to achieve
clearance is not a good practice. Its easy enough to get thinner shims
to get the clearance and if this does not work, then I would suggest
that they have undercut the valve seats far too much. Once the valve
stems have been ground, they become next to useless for any performance
applications - need very thick shims in a good head etc. If they suggest
grinding the cam buckets, grab your engine and get it out of there fast.


You really have to be careful who you give an Alfa head to, or come to
that just about any engine as I found out after trying a recommended
engine builder in Wellington who destroyed our Formula Ford engine.

Ciao tutti
Les in Wellington, NZ

Date: Thu, 1 Apr 2004 16:57:44 +1200
> From: Michael Findlay <michael@domain.elided>
> Subject: [alfa] Grinding valve stems
>
> A couple of questions regarding grinding Alfa valve stems to
> achieve clearance after a valve job. I have my 1750 head at a
> reputable engine shop in Dunedin, New Zealand. They suggest
> that it is okay to shorten the valve stem. I passed on the
> standard warning about sodium-filled valves and there was a
> bit of head scratching. They have never heard of a valve
> blowing up and I would guess that there is a reasonable
> amount of material at the top of the stem so that they will
> not breach the internals. However, is this good practice?
> Does it affect the hardening of the valve stem? How much can
> be removed?
>
> Michael Findlay
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