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Eagledriver Eagledriver is offline
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Join Date: May 2003
Posts: 3,231
I assume those cam numbers are "S" cams. I think this is common for that combination. I had to have my valve pockets deepened about .030 inches on the intake and .020 on the exhaust with the same setup you have.

If you look in the original factory manuals they allow a very tight tolerance (I think it was 1mm). I think I could have achieved this tolerance with slightly retarding the cams and using the thicker base shims. I wasn't comfortable with that so I did the above cutting. I suspect the engines from the factory had the very tight tolerances that you are seeing.

Ted Robinson at German Precision can cut the pockets deeper for you. There is lots of metal on the bottom of those pistons to accomidate the cutting.

72 Carrera RS replica, Spec 911 racer
Old 10-23-2005, 05:46 PM
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