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With TDC now set, we can move on to determining the camshaft's position relative to TDC. This simple illustration reveals the relationship of the intake lobe centerline to TDC. This particular camshaft uses an intake centerline of 109 degrees, which is the number of crankshaft degrees after top dead center (ATDC). This illustration makes it easy to see that if the cam measures 113 degrees ATDC, then the intake lobe is opening and closing later (retarded). Conversely, if the intake centerline is at 104 degrees ATDC, it is opening and closing earlier, which means the cam is advanced relative to TDC.