Advertised cam duration 0.006" or 0.004" lifter rise

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Retlaw01XJ
Movin on up ^
Movin on up ^
Posts: 307
Joined: November 23rd, 2011, 10:40 pm
Stroker Displacement: 4.6
Vehicle Year: 2001
Vehicle Make: Jeep
Vehicle Model: Cherokee

Advertised cam duration 0.006" or 0.004" lifter rise

Post by Retlaw01XJ »

Profiled my stock 2001 cam the other day. Specs were generally within a degree of those published. :D
But...
Don't most aftermarket companies spec their advertised duration at 0.006" lifter rise?
The stock cam only matched published specs at 0.004" lifter rise. That makes comparison with other cams more difficult.

My results:
Intake duration at 0.004"= 252 deg (published = 253.3 deg)
Intake duration at 0.006"= 243.5 deg
Intake duration at 0.050"= 189 deg

Exhaust Duration at 0.004"= 258.5 deg (published= 259 deg)
Exhaust Duration at 0.006"= 251.5 deg
Exhaust Duration at 0.050"= 192 deg

Calculated centerlines were right on when using .004 and .006" points, but lobe centerline shifts when using the 0.050" open/close points.
Max lift is also shifted from the published centerlines.... apparently the lobe is asymetrical.
Walt K
Eastern Pa
2001 Cherokee 4.6 stroker 90 day build
Buick GS's and Saab turbos for other days...
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