What the . . . ? Fattie adjusting screws!

On Fri, 10 Dec 2004 10:04:23 -0800 "Mike Rocket J. Squirrel Elliott"
et> wrote:

>On 12/9/2004 10:13 PM Colin wrote:

>> The 8mm
>> rocker arms can be ground down .060" under the threaded area that
>> accepts the swivelfoot adjusters to help you achieve sufficient
>> clearance.
>
>How did you grind them? John Connolly sez to grind them lengthwise, not
>crosswise, or the rockers will be weakened.

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.

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Jim Adney
Madison, WI 53711 USA
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