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On Mon, 2005-11-14 at 09:08, Jim Adney wrote: > On 14 Nov 2005 at 14:26, Matthew Jones wrote: > > > Someone once told me the valve head was welded to the stem, and that's where > > they broke, because it was a weak point. Fits the symptoms but thinking about > > it they would never make them that way! > > They actually do! If you take a magnet to one you will find that there are 3 or > 4 different "zones" from the head to the stem which have different magnetic > properties. It's amazing, but the head materials are quite special, so they are > attached somehow. As odd as this seems, I think it is a rather standard process > for making valves. > Mahle is actually making valves with hollow stems and stamped from metal. They are in the testing stages right now. They have engines that have gone over 100K miles with them. Probably be in production in a couple years. The lighter the valve, they higher the rpms for the engine. -- Russ Wolfe '71 FB AT '66 FB MT '64 T34 (not running) '65 T1 (not running) '05 KIA Sorento SUV russw@classicvw.org http://www.classicvw.org ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ List info at http://www.vwtype3.org/list | mailto:gregm@vwtype3.org ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~