I use an oval carbide die grinder burr in a drill press. This basically just puts a bit of a countersink in the face of the rocker that allows the tapered backside of the swivel foot to slip in there. This is quick and easy, and removes no excess metal and almost no strength.
When shimming the rocker stands, you DON'T want to just shim them out willy-nilly. They really should not be moved out any more than the valve seats have been sunk by all previous valve jobs. The geometry here is critical to valve guide lifetime, and VW did a good job of engineering this.
I worked thru the math on this about 10 years ago and discovered that VW put the rocker shaft exactly where it needed to be to minimize valve guide wear. The calculation I did was for stock springs and valves. I have not redone it for different parts. The calculations came out to within about .010" of where I figured the rockers originally were, which was actually about as close as I could measure it.
I find I can get by with about .020-.030" in shims if I also shorten the pushrods by about 1 mm. I have several engines which have gone more than 100,000 miles with no abnormal wear when done like this.
------------------------------------------------ Jim Adney snipped-for-privacy@vwtype3.org Madison, WI 53711 USA
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