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techtalk:ref:oil07 [2020/03/29 23:06] hippysmack [Anti-Drainback Valve] |
techtalk:ref:oil07 [2020/09/09 02:55] hippysmack [Anti-Drainback Valve] |
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| This valve is usually in the form of a rubber gasket which allows the free flow of oil through the filter in the normal direction. \\ | This valve is usually in the form of a rubber gasket which allows the free flow of oil through the filter in the normal direction. \\ | ||
| But when the engine is shut down, it prevents the oil in the filter from draining back to the crankcase (oil pump in the case of Sportsters). \\ | But when the engine is shut down, it prevents the oil in the filter from draining back to the crankcase (oil pump in the case of Sportsters). \\ | ||
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| + | There is no need to install a filter with an anti-drainback valve on a Sportster. \\ | ||
| + | The oil tank sits higher than the oil filter housing. So if any oil could drain back, oil can't run uphill by itself. \\ | ||
| + | Sportsters have an inherent problem with oil gravity draining into the engine when the engine is shut off and it sits for a while (sit-sumping). \\ | ||
| + | This is due to either a worn check valve or worn clearances in the oil pump. \\ | ||
| + | So, oil in a Sportster will be pushed against the filter at all times without a drainback valve in the filter. \\ | ||
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| This is from a HD Parts and Accessories Bulletin (PAB-398) dated 11-1-1988. Low restriction oil filter (63806-83) has been obsoleted. \\ | This is from a HD Parts and Accessories Bulletin (PAB-398) dated 11-1-1988. Low restriction oil filter (63806-83) has been obsoleted. \\ | ||
