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techtalk:ih:oil03c [2019/08/05 13:01] ixl2relax [IH: Oiling & Lubrication - Sub-03A] |
techtalk:ih:oil03c [2021/11/07 22:12] hippysmack [Scratches on Gerotors or Mating Surfaces] |
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====== IH: Oiling & Lubrication - Sub-03C ====== | ====== IH: Oiling & Lubrication - Sub-03C ====== | ||
====== 77-85 Oil Pump Damage and Repair ====== | ====== 77-85 Oil Pump Damage and Repair ====== | ||
- | ====== Cracks in Housing or Cover ====== | ||
- | This cover was cracked at the oil pressure switch end. \\ | ||
- | The crack was welded over and a Dremil tool was used to reshape the cover. \\ | ||
- | Due to warpage during welding, the threads need to be chased with a tap to straighten them back out. \\ | ||
- | | Repair on oil pump cover ((photos by Farmer00-1 of the XLFORUM http://xlforum.net/forums/showthread.php?t=554323)) || | ||
- | |{{:techtalk:ih:oil:cracked_oil_pump_cover_1_by_acb2.jpg?direct&300|}}|{{:techtalk:ih:oil:cracked_oil_pump_cover_2_by_acb2.jpg?direct&300|}}| | ||
- | ====== Scratches on Gerotors or Mating Surfaces ====== | ||
- | * Many used oil pumps have scratches on both the gerotors and pump surfaces that the gerotors ride on. | ||
- | * But, there is one certain spot that seems to be scratched more times than others. ((Hippysmack of the XLFORUM http://xlforum.net/forums/showthread.php?t=2071153&page=6)) | ||
- | * It's on the larger of the two pads in the pump body and the cover seem to usually have more wear. | ||
- | * Sometimes, the small pad is scratched or damaged also but not always. | ||
- | * The gap between the inner and outer gerotors on both the feed and return sides tends to be scratched as in the pics below. | ||
- | * Debris caught between these two gears cannot slide over and fall to the other cavity and out of the pump. | ||
- | * It gets locked between the gears and ripped across the aluminum surface. | ||
- | |||
- | |{{:techtalk:ih:oil:77-85_oil_pump_cover_11_by_hippysmack.jpg?direct&500|}}|{{:techtalk:ih:oil:77-85_oil_pump_cover_12_by_hippysmack.jpg?direct&500|}}| | ||
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- | |{{:techtalk:ih:oil:77-85_oil_pump_cover_7_by_hippysmack.jpg?direct&500|}}|{{:techtalk:ih:oil:77-85_oil_pump_cover_8_by_hippysmack.jpg?direct&500|}}| | ||
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- | * In theory, no particles of any size should be able to spin around to the small pad due to the pressure generated by the spring washer and the gerotor spacing there. | ||
- | * Also, any debris picked up from the source side cavity should drop down into the feed side cavity and out of the pump. | ||
- | * The side toward the motor is where oil is transferred to and from the pump. | ||
- | * The inner and outer gears come together on the other side (right side). | ||
- | * This spacing relationship doesn't change between the motor side or the outside of the pump due to the offset gearshaft. | ||
- | |||
- | * But in reality, debris gets caught in or between the gears and gets dragged over the aluminum flats. | ||
- | * Some then find their way under the gerotors while the spring washer flexes from the stress. | ||
- | * The debris spins around under the gerotors and wears scratches in the flats (pads) or worse. | ||
- | |||
- | |{{:techtalk:ih:oil:77-85_oil_pump_cover_9a_by_hippysmack.jpg?direct&500|}}|{{:techtalk:ih:oil:77-85_oil_pump_cover_10a_by_hippysmack.jpg?direct&500|}}| | ||
- | | Gerotor rotation ((photos by Hippysmack http://xlforum.net/forums/showthread.php?t=2071153&page=6)) || | ||
- | |||
- | |{{:techtalk:ih:oil:83_oil_pump_by_sc72.jpg?direct&300|}}|{{:techtalk:ih:oil:77_oil_pump_gearshaft_pin_broke_by_77_iron.jpg?direct&500|}}| | ||
- | | Oil pump from an 83 model ((photo by sc72 of the XLFORUM http://xlforum.net/forums/showthread.php?t=1717592&page=15)) | Gearshaft pin broke off into this 77 model ((photo by 77 iron of the XLFORUM http://xlforum.net/forums/showthread.php?t=1831941&page=2)) | | ||
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- | * There should be some reduced pressure because of the scratches. | ||
- | * Pressure generated to the output cavity can squirt back to the input side through these scratches. | ||
- | * How much pressure loss would depend on the width, depth, length of the scratches and oil viscosity. | ||
- | * To make the pump inoperative or not make pressure (from the scratches alone); | ||
- | * The scratches would have to be proportional to the relative volume of all four gerotor reservoirs combined. | ||
- | * Then, the check valve would have to accept less pressure flow than the backpressure from the pump. | ||
- | * The gerotor surface in the cover would have to be eat up pretty bad to make the pump completely ineffective. | ||
- | * The pump would have less pressure loss with multi-weight or straight weight oil when cold than hot. | ||
- | * They'll both flow faster when hot. | ||