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2.7RACER 2.7RACER is offline
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Join Date: Jun 2004
Location: Rio Rancho, New Mexico
Posts: 1,326
You missed the line above the sentence. I was using Jack's 0.47mm spec he quoted along with my own information for HIS CIS cams.

"Actually the cam has begun to open the intake valve before TDC.
The 0.47mm spec refers to the movement of the valve at TDC Z1.
At 6 degrees after TDC (just past the 5 degree mark) the indicator should read 1.0mm.
1.0mm (0.039") is the standard for Porsches. American cam makers use 0.050".

My comment regarding 1.0mm for Porsches as compared to 0.050" for American makers is useful when comparing cam specs.
As I said for Jacks cam, he would set the timing at TDC Z1, (crossover), at 0.47mm. From Bruce Andersons Cam specs for this motor, the intake opens at 6 degees after TDC. I merely pointed out at that point, (6 degees after TDC) the dial indicator would read 1.0mm.
Basically explaining the relationship of the .47mm at TDC and 6 degrees after TDC, whch would be 1.0mm.
I'm afraid explaining cam timing without pictures is similar to writing instruction on how to tie your shoe laces.
Jim Williams surmised exactly what I was saying.
Ultimately, more pictures along with a descripition would have worked better. Thanks for your interest and comments.
'76 911S 2.7, webers, solex cams, JE pistons, '74 exhaust, 23 & 28 torsion bars, 930 calipers & rotors, Hoosiers on 8's & 9's.
'85 911 Carrera, stock, just painted, Orient Red
Old 11-29-2005, 09:51 PM
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