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mark houghton mark houghton is offline
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Join Date: Jul 2008
Location: Central Washington State
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I spent some quality time last night reading Bruce's and Wayne's books on the care and feeding of the 911, relative to cams, and I kinda walked away with the impression from their quotes that high lift cams aren't compatible with CIS for a couple reasons: domed pistons and possible collision with valves, and valve overlap with both intake and exhaust valves being open briefly at the same time, causing oscillations in the CIS fuel delivery (as in a bouncing metering arm, I guess).

I guess the key word here is "high lift", as he (they) were referencing "S" cams. Apparently 964 or SC cams aren't considered high lift, as evidenced by the fact that many people run them in their 930's. I will eventually be running with an SC330 grind, which I understand has the duration of a 964 with the lift of the SC, and was made to run in place of the SC cam for stock lift applications.

Comments?
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Mark H. 1987 930, GP White, Wevo shifter, Borla exhaust, stock everything else. The result of a massive Pelicanite good will fire recovery effort. Truely an open book, ready for the slippery slopes to modification.
Old 11-24-2009, 10:47 AM
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