In all cases, the intermittent rotation of the fuel distribution shaft prevents the shaft from rotating at a time when the discharge of a highly pressurized fuel pulse applies a high side load to the shaft which in turn can generate {HEAD ~ high frictional forces} between the fuel distribution shaft and {TAIL ~ the surrounding housing} 
In all cases , the intermittent rotation of the fuel distribution shaft prevents the shaft from rotating at a time when the discharge of a highly pressurized fuel pulse applies a high side load to the shaft which in turn can generate { HEAD ~ high frictional forces } between the fuel distribution shaft and { TAIL ~ the surrounding housing }
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