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| techtalk:ih:oil03p [2025/02/26 19:55] – [Inspect the oil pump cover and body] hippysmack | techtalk:ih:oil03p [2025/02/26 20:36] (current) – hippysmack |
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| ===== Inspect the oil pump cover and body ===== | ===== Inspect the oil pump cover and body ===== |
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| === Look for debris while disassembling === | ==== Look for debris while disassembling ==== |
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| Grit / Debris found in the oil pump can give clues to potential motor problems.\\ | Grit / Debris found in the oil pump can give clues to potential motor problems.\\ |
| |{{:techtalk:evo:oil:oil_pump_damage_3_by_-_-_-_annotated.jpg?direct&300}}| | |{{:techtalk:evo:oil:oil_pump_damage_3_by_-_-_-_annotated.jpg?direct&300}}| |
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| === Inspect the ridge in the cover === | ==== Inspect the ridge in the cover ==== |
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| * Using a straightedge across the feed gerotor set (installed) surface; \\ Measurement should be taken with a feeler gauge from the gerotor surface to the ridge of the edge of the aluminum cover. \\ The thin, feed gerotors (26492-75) in the oil pump cover (26486-75) should extend .001"-.005" above the cover's aluminum ridge. \\ The later feed gerotors extend up to .011" above the ridge. \\ If the feed gerotors do not extend above the ridge within the specified range, \\ Remove and sand the ridge evenly until the gerotors extend properly when inserted. \\ Lay some sandpaper on a flat surface (#280 grit then #400 grit to finish). \\ Invert the cover and sand the ridge then check the measurement with a micrometer. \\ Make sure that both the inner and outer gerotors are the same thickness also. | * Using a straightedge across the feed gerotor set (installed) surface; \\ Measurement should be taken with a feeler gauge from the gerotor surface to the ridge of the edge of the aluminum cover. \\ The thin, feed gerotors (26492-75) in the oil pump cover (26486-75) should extend .001"-.005" above the cover's aluminum ridge. \\ The later feed gerotors extend up to .011" above the ridge. \\ If the feed gerotors do not extend above the ridge within the specified range, \\ Remove and sand the ridge evenly until the gerotors extend properly when inserted. \\ Lay some sandpaper on a flat surface (#280 grit then #400 grit to finish). \\ Invert the cover and sand the ridge then check the measurement with a micrometer. \\ Make sure that both the inner and outer gerotors are the same thickness also. |
| {{:techtalk:ih:oil:1977-1985_oil_pump_cover-_checking_clearance_by_hippysmack.jpg?direct&300}}((photo by Hippysmack)) | {{:techtalk:ih:oil:1977-1985_oil_pump_cover-_checking_clearance_by_hippysmack.jpg?direct&300}}((photo by Hippysmack)) |
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| === Inspect the gerotor surface for flatness in the oil pump cover and housing === | ==== Inspect the gerotor surface for flatness in the oil pump cover and housing ==== |
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| An oil pump cover found with an uneven gerotor surface should be removed. \\ If the gerotor widths measure equally but they are not equal in height when placed into the cover, the cover surface is not flat. \\ If the gerotors will not sit flat in the cover then the cover should be replaced. \\ Be sure to check the gerotors in the new/replacement cover using a straight edge to assure a level surface and the proper elevation above the ridge. \\ Be sure to check the gerotor surface in the housing also. | An oil pump cover found with an uneven gerotor surface should be removed. \\ If the gerotor widths measure equally but they are not equal in height when placed into the cover, the cover surface is not flat. \\ If the gerotors will not sit flat in the cover then the cover should be replaced. \\ Be sure to check the gerotors in the new/replacement cover using a straight edge to assure a level surface and the proper elevation above the ridge. \\ Be sure to check the gerotor surface in the housing also. |
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| === Inspect the gerotor surface in the cover and housing for deep scratches or gouges === | ==== Inspect the gerotor surface in the cover and housing for deep scratches or gouges ==== |
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| Many (most perhaps) 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 https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/ironhead-sportster-motorcycle-talk-1957-1985/194881-let-s-study-the-77-85-oil-pump-parts-and-changes-and-when/page6?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 teeth and ripped across the aluminum surface. \\ In theory, no particles of any size should be able to spin around to the small pad. \\ This is mainly 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 gerotors 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. \\ There should be some amount of reduced pressure because of the scratches (depending on how may and how deep). \\ 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 at the time. \\ 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. \\ | Gerotor rotation (cover shown) ((photos by Hippysmack https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/ironhead-sportster-motorcycle-talk-1957-1985/194881-let-s-study-the-77-85-oil-pump-parts-and-changes-and-when/page6?t=2071153&page=6)) || | Many (most perhaps) 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 https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/ironhead-sportster-motorcycle-talk-1957-1985/194881-let-s-study-the-77-85-oil-pump-parts-and-changes-and-when/page6?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 teeth and ripped across the aluminum surface. \\ In theory, no particles of any size should be able to spin around to the small pad. \\ This is mainly 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 gerotors 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. \\ There should be some amount of reduced pressure because of the scratches (depending on how may and how deep). \\ 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 at the time. \\ 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. \\ | Gerotor rotation (cover shown) ((photos by Hippysmack https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/ironhead-sportster-motorcycle-talk-1957-1985/194881-let-s-study-the-77-85-oil-pump-parts-and-changes-and-when/page6?t=2071153&page=6)) || |
| {{:techtalk:ih:oil:1977-e1983_oil_pump_body_scratches_1_by_hippysmack.jpg?direct&300}}{{:techtalk:ih:oil:1977-e1983_oil_pump_body_scratches_2_by_hippysmack.jpg?direct&300}}{{:techtalk:ih:oil:1977-e1983_oil_pump_body_scratches_3_by_hippysmack.jpg?direct&300}} | {{:techtalk:ih:oil:1977-e1983_oil_pump_body_scratches_1_by_hippysmack.jpg?direct&300}}{{:techtalk:ih:oil:1977-e1983_oil_pump_body_scratches_2_by_hippysmack.jpg?direct&300}}{{:techtalk:ih:oil:1977-e1983_oil_pump_body_scratches_3_by_hippysmack.jpg?direct&300}} |
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| === Classifying Scratches in Gerotor Surfaces === | ==== Classifying Scratches in Gerotor Surfaces ==== |
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| HD says that if there are any notable scratches on the gerotor riding surfaces in the oil pump housing or cover, then they should be replaced. \\ Hagen–Poiseuille Equation to calculate flow pressure drop: ((Hippysmack https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-general-discussion-and-problems/203901-sportster-oil-pressure-and-dynamics/page9)) \\ Without getting into the weeds on figures (that change with every individual pump), Hagen/Poiseuille determined that the laminar flow rate of an incompressible fluid along a pipe is proportional to the fourth power of the pipe's radius. That is, doubling the diameter of an outlet increases the flow rate by 16 fold (r4). The larger the outlet, the greater the flow. But in the instance of pump internal leakage, there are two outlets, upstream back to the inlet and downstream into the engine. \\ Result: In order for the pump to not produce any flow to the outlet side (downstream), total ID of the clearances and scratches would have to be twice the ID of the outlet of the pump using Hagen/Poiseuille. \\ Further comments by Hippysmack: | HD says that if there are any notable scratches on the gerotor riding surfaces in the oil pump housing or cover, then they should be replaced. \\ Hagen–Poiseuille Equation to calculate flow pressure drop: ((Hippysmack https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-general-discussion-and-problems/203901-sportster-oil-pressure-and-dynamics/page9)) \\ Without getting into the weeds on figures (that change with every individual pump), Hagen/Poiseuille determined that the laminar flow rate of an incompressible fluid along a pipe is proportional to the fourth power of the pipe's radius. That is, doubling the diameter of an outlet increases the flow rate by 16 fold (r4). The larger the outlet, the greater the flow. But in the instance of pump internal leakage, there are two outlets, upstream back to the inlet and downstream into the engine. \\ Result: In order for the pump to not produce any flow to the outlet side (downstream), total ID of the clearances and scratches would have to be twice the ID of the outlet of the pump using Hagen/Poiseuille. \\ |
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| <blockquote>In thinking about it; | |
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| | Further comments by Hippysmack. In thinking about it; |
| * Inlet side of the pump feed cavity is first fed by gravity from the oil tank and then by suction assist (vacuum pressure) created by the spinning feed gerotors. | * Inlet side of the pump feed cavity is first fed by gravity from the oil tank and then by suction assist (vacuum pressure) created by the spinning feed gerotors. |
| * Inlet side of the pump return cavity is fed solely on suction from the spinning return gerotors. \\ Oil is sucked uphill from the crankcase sump thru a small drilled oil galley in the case to the oil pump. | * Inlet side of the pump return cavity is fed solely on suction from the spinning return gerotors. \\ Oil is sucked uphill from the crankcase sump thru a small drilled oil galley in the case to the oil pump. |
| |{{:techtalk:ih:oil:1983_sportster_oil_pump_body_by_sc72.jpg?direct&300}}|{{:techtalk:ih:oil:1977-e1983_oil_pump_scratches_by_rolli.jpg?direct&300}}|{{:techtalk:ih:oil:1978_oil_pump_body_by_dirtycory.jpg?direct&300}}| | |{{:techtalk:ih:oil:1983_sportster_oil_pump_body_by_sc72.jpg?direct&300}}|{{:techtalk:ih:oil:1977-e1983_oil_pump_scratches_by_rolli.jpg?direct&300}}|{{:techtalk:ih:oil:1978_oil_pump_body_by_dirtycory.jpg?direct&300}}| |
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| === Check for cracks in the housing and cover === | ==== Check for cracks in the housing and cover ==== |
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| The cover below was cracked at the oil pressure switch end from tightening the pressure switch too tight. \\ 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. | The cover below was cracked at the oil pressure switch end from tightening the pressure switch too tight. \\ 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. |
| |{{: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}}|{{:techtalk:evo:oil:oil_pressure_switch_threads_by_hippysmack.png?direct&300}}| | |{{: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}}|{{:techtalk:evo:oil:oil_pressure_switch_threads_by_hippysmack.png?direct&300}}| |
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| === Inspect the Housing Roll Pin === | ==== Inspect the Housing Roll Pin ==== |
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| The roll pin is installed into the "shelf" between the housing bores and it normally shouldn't see any shear force. \\ A roll pin is a spring, that's what keeps it in place. It's not solid because it's NOT supposed to shear. ((kitabel of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/ironhead-sportster-motorcycle-talk-1957-1985/203361-oil-pump-split-pin-removal)) | The roll pin is installed into the "shelf" between the housing bores and it normally shouldn't see any shear force. \\ A roll pin is a spring, that's what keeps it in place. It's not solid because it's NOT supposed to shear. ((kitabel of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/ironhead-sportster-motorcycle-talk-1957-1985/203361-oil-pump-split-pin-removal)) |
| If the roll pin comes out, it will cause damage to the oil pump. If it gets lodged between the inner and outer gerotors, it'll most likely crack the outer piece (weaker of the two pieces). If it gets under the gerotors, it'll get dragged across the gerotor surface in the pump housing or cover. This will end up in scratches on the machined surface and lower oil pressure from the pump due to the scratches. With the roll pin out, the outer plate, under pressure, can spin and wallow out the feed bore in the housing around the plate. | If the roll pin comes out, it will cause damage to the oil pump. If it gets lodged between the inner and outer gerotors, it'll most likely crack the outer piece (weaker of the two pieces). If it gets under the gerotors, it'll get dragged across the gerotor surface in the pump housing or cover. This will end up in scratches on the machined surface and lower oil pressure from the pump due to the scratches. With the roll pin out, the outer plate, under pressure, can spin and wallow out the feed bore in the housing around the plate. |
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| **If needed, below are some possible ways to remove the roll pin**. | |
| | **If needed, below are some possible ways to remove the roll pin**. \\ |
| | Note: Vise Grips will most likely slip off the pin and damage it further, but more importantly damage the pump housing. Heat will most likely expand the aluminum around the pin, squeezing it harder around the pin. these are generally bad ideas for removing the pin. |
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| - You can try a side dike wire cutter and a little electrical freeze spray on the aluminum. | - You can try a side dike wire cutter and a little electrical freeze spray on the aluminum. |
| * Use a metal cutting blade on a Dremil cutting tool to cut the old pin flush with the "shelf" in the pump housing. Make sure there are no splinters left on the existing pin (needs to be flush to the shelf it sits on) and the shelf has no gouges that would push on the divider plates when installed. | * Use a metal cutting blade on a Dremil cutting tool to cut the old pin flush with the "shelf" in the pump housing. Make sure there are no splinters left on the existing pin (needs to be flush to the shelf it sits on) and the shelf has no gouges that would push on the divider plates when installed. |
| * Blow out the new hole with compressed air, press the new roll pin into the new hole and you're done. | * Blow out the new hole with compressed air, press the new roll pin into the new hole and you're done. |
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| **Generally bad ideas for removing the pin**. | |
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| * Vise Grips will most likely slip off the pin and damage it further, but more importantly damage the pump housing. | |
| * Heat will most likely expand the aluminum around the pin, squeezing it harder around the pin. | |
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| **The roll pin below was damaged by trying to remove it**. \\ It was removed using electrical side cutters by XLF member, billeuze. ((https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/ironhead-sportster-motorcycle-talk-1957-1985/203361-oil-pump-split-pin-removal/page2)) \\ Carefully protect the base and sides of the pump body. \\ Odd parts were put inside the pump for a nice height for a fulcrum for the side cutters. \\ I squeezed and pried it out. It took 4 or five pries to walk it all the way out. ((photos by billeuze)) | **The roll pin below was damaged by trying to remove it**. \\ It was removed using electrical side cutters by XLF member, billeuze. ((https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/ironhead-sportster-motorcycle-talk-1957-1985/203361-oil-pump-split-pin-removal/page2)) \\ Carefully protect the base and sides of the pump body. \\ Odd parts were put inside the pump for a nice height for a fulcrum for the side cutters. \\ I squeezed and pried it out. It took 4 or five pries to walk it all the way out. ((photos by billeuze)) |
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| {{:techtalk:ih:oil:1977-e1983_sportster_oil_pump_roll_pin_removal_pic3_by_billeuze.jpg?direct&400}}{{:techtalk:ih:oil:1977-e1983_sportster_oil_pump_roll_pin_removal_pic4_by_billeuze.jpg?direct&400}} | {{:techtalk:ih:oil:1977-e1983_sportster_oil_pump_roll_pin_removal_pic3_by_billeuze.jpg?direct&400}}{{:techtalk:ih:oil:1977-e1983_sportster_oil_pump_roll_pin_removal_pic4_by_billeuze.jpg?direct&400}} |
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| | **The roll pin below was damaged and a second roll pin was added to keep from removing the original pin**. \\ |
| | In order to add the second pin, additional slots have to be cut into both the inner and outer plates since they are both captured by the roll pin. \\ |
| | {{:techtalk:ih:oil:1980_oil_pump_pin_and_divider_plate_mod_pic1_by_billy1200.jpg?direct&400|}} {{:techtalk:ih:oil:1980_oil_pump_pin_and_divider_plate_mod_pic2_by_billy1200.jpg?direct&400|}} \\ |
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| ===== Inspect the gearshaft and bushings for damage or wear ===== | ===== Inspect the gearshaft and bushings for damage or wear ===== |
