NOT the primary timing chain This timing chain is not the main mechanism operating the cam sprockets. Th e main mechanism is belt driven and runs off the intake cam sprocket. This chain runs the exhaust cam shaft from sprockets located at the rear of the camshafts. - This timing chain is not the main mechanism operating the cam sprockets. Th e main mechanism is belt driven and runs off the intake cam sprocket. This chain runs the exhaust cam shaft from sprockets located at the rear of the camshafts. -