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snowman snowman is offline
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Join Date: Feb 2003
Location: So California
Posts: 3,787
rcwaldo stated the most likely cause.

Question- could this also be caused by pre ignition? In other words head studs pulled or stretched due to extreem pressure generated by pre ignition due to high compression ratio. See Waynes comments above.

In any case I would use only copper shims on rebuild. Thick copper shims are available if needed.

Long lasting street engine? CR on a Porsche is effectively about 1 point higher than on a water cooled engine according to Bruce Andersons book. Using premium gas with an ignition that includes knock detection would seem to limit the CR to 9.8:1. Otherwise without the knock detector to maybe 9.3 to one max. Thats for long lasting.

Your case almost certainly needs to be re decked as well.

Last edited by snowman; 12-30-2004 at 03:52 PM..
Old 12-30-2004, 03:40 PM
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