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techtalk:ref:oil21 [2022/09/05 05:03] – hippysmacktechtalk:ref:oil21 [2024/09/29 20:49] (current) – [Normal Oil Migration] hippysmack
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 In that case, the static pressure would go down to around .225 PSI at operating temp. \\ In that case, the static pressure would go down to around .225 PSI at operating temp. \\
  
-Lowering the oil level to the low mark on the dipstick will lower the pressure at the oil pump. \\+Lowering the oil level to the low mark on the dipstick will lower the pressure at the oil pump slightly. \\ 
 +But it is not gravity that actually pulls oil into the pump. It's vacuum created by the gears / gerotors that does most of the oil gathering. \\ 
 +A change in location elevation from sea level can also change the pressure at the oil pump. \\
 The mark is there as a minimum oil level to attain enough pressure at the pump to keep down cavitation in the oil pump. \\ The mark is there as a minimum oil level to attain enough pressure at the pump to keep down cavitation in the oil pump. \\
-A change in location elevation from sea level will change the pressure at the oil pump. \\ + 
-The roughness of the feed hose ID will lower pressure at the pump due to the affects of friction. \\ +Below are some examples of things that could lead to pump cavitation; \\ 
-Kinks in the feed hose or internal shrinkage of the inside walls of the feed hose will lower pressure at the oil pump. \\  +  * The roughness of the feed hose ID can lower pressure at the pump due to the affects of friction. 
-Changing the inlet fitting to a smaller ID will lower pressure on the hose side of the fitting. \\ +  * Kinks in the feed hose or internal shrinkage of the inside walls of the feed hose can lower pressure at the oil pump. 
-The static pressure at the inlet is changed further upon vacuum from the oil pump inlet. \\ +  * Changing the inlet fitting to a smaller ID can lower pressure on the hose side of the fitting. \\ The static pressure at the inlet is changed further upon vacuum from the oil pump inlet. \\ The hose fitting is a restriction where flow (from vacuum)of pump gear action lowers static on the hose pressure. \\
-The hose fitting is a restriction where flow (from vacuum)of pump gear action lowers static on the hose pressure. \\+
  
 {{:techtalk:ref:oil:sportster_oil_pressure_-_oil_tank_head_pressure_by_hippysmack.png?direct&400|}} ((drawing by Hippysmack)) \\ {{:techtalk:ref:oil:sportster_oil_pressure_-_oil_tank_head_pressure_by_hippysmack.png?direct&400|}} ((drawing by Hippysmack)) \\
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 |  1977-E1983 Sportster Oil Pump Feed \\ Gerotor Positions - Supply Side ((photo by Hippysmack))  |  1977-E1983 Sportster Oil Pump Feed \\ Gerotor Positions - Feed Side ((photo by Hippysmack))  |   |  1977-E1983 Sportster Oil Pump Feed \\ Gerotor Positions - Supply Side ((photo by Hippysmack))  |  1977-E1983 Sportster Oil Pump Feed \\ Gerotor Positions - Feed Side ((photo by Hippysmack))  |  
 |{{:techtalk:ref:oil:sportster_oil_pressure_-_oil_pump_supply_side_by_hippysmack.jpg?direct&400|}}|{{:techtalk:ref:oil:sportster_oil_pressure_-_oil_pump_feed_side_by_hippysmack.jpg?direct&400|}}| |{{:techtalk:ref:oil:sportster_oil_pressure_-_oil_pump_supply_side_by_hippysmack.jpg?direct&400|}}|{{:techtalk:ref:oil:sportster_oil_pressure_-_oil_pump_feed_side_by_hippysmack.jpg?direct&400|}}|
- 
  
 ====== Oil Pump Suction ====== ====== Oil Pump Suction ======
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 |  Video of no vacuum pressure w/ no oil in hose ((video by Hippysmack))  | |  Video of no vacuum pressure w/ no oil in hose ((video by Hippysmack))  |
-|{{:video:oil_pump_flow_testing_video-_vacuum_on_pump_return_port_by_hippysmack.mp4|}}|+|{{video:100-oil_pump_flow_testing_-_vacuum_on_pump_return_port_by_hippysmack.mp4|}}|
  
 ====== Oil Pump Internal Oil Leakage ====== ====== Oil Pump Internal Oil Leakage ======
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 Due to the rotating gears and gearshaft, oil is pulled through the clearances. \\ Due to the rotating gears and gearshaft, oil is pulled through the clearances. \\
 This is normal and the clearances are there to cut down on heat buildup and galling. \\ This is normal and the clearances are there to cut down on heat buildup and galling. \\
 +
 +|**Dry Gear face clearance**: The gears in the pump have a top and bottom surface and by indusrty standards is called the (sides). I generally called that the (faces) since bikers would think the sides to be the area between the teeth and the sides of the gear bore in the pump. The face clearance in gear pumps is finally established by the cover gasket thickness. The gear height also plays a factor in that clearance. The installed gear height in the pump according to the 70-78 FSM is .0005" below to .0025 above the pump body gasket surface. The lower the gear sits in the gear well in the body, the more the clearance up top and the higher it sits, the less the clearance will be. So once the gasket and cover is installed, the running clearance is set. **Running Gear Face Clearance**: So now you should have lubed the gears before finally installing them in the pump to keep wear down on startup. When you fire up the motor, oil is pulled into the face clearances by the rotation of the gears and that "oil migration" should be, by design, a minimal amount of oil. The gears turn by the breather gear pins and/or pin and woodruff key respective of breather gear type. The pin/key is not a press fit in the slot of the gears so the gears have the ability to float up or down during operation. Oil is pulled into the face clearances and should be equal amounts on top and bottom of the gears as the gears adjust their height according to the pressure of the migrating oil each side. This should reduce the clearance that was measured during assembly by roughly 1/2 in a running pump. **Slippage**: We've established the clearances and designed amount of oil to be recirculated between the feed and return chambers. That clearance keeps gear to mating surfaces apart and provides cooling across the gear faces. The amount of oil lost from the feed chamber (due to recirculation) is commonly referred to as slip or slippage or recirculation. This is the crux of oil pump efficiency deciding how much oil the pump will carry between the teeth as opposed to how much can actually be delivered to the motor and at what percentage throughout the RPM changes. But another part of pump efficiency involves the teeth to pump wall clearance not discussed here. **What feeds oil across the gear faces**: On idle, as pressure builds in the outlet chamber of the pump, some of that pressurized oil pushes to the gear faces, into the clearances and rotates around to the pump suction chamber, still under pressure. **How face oil migration affects the suction of the gears**: If the migrating oil was not under pump pressure, it would simply be referred to as an additional oil inlet as far as the suction chamber goes. But the positive pressure into the suction chamber is now reducing the amount of effective vacuum that is being created by the closing of the gears. This does two main things; It lowers suction on the hose from the oil tank which in turn lowers the amount of oil pulled into the pump per revolution. It also creates more heat to the migrating oil in the process.
 +
 +
  
 Below is a drawing of a 1986-1990 Sportster Oil Pump. \\ Below is a drawing of a 1986-1990 Sportster Oil Pump. \\
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 {{:techtalk:ref:oil:sportster_oil_pressure_-_oil_pump_oil_migration_1977-1985_by_hippysmack.png?direct&400|}} ((drawing by Hippysmack)) {{:techtalk:ref:oil:sportster_oil_pressure_-_oil_pump_oil_migration_1986-1990_by_hippysmack.png?direct&400|}} ((drawing by Hippysmack)) \\ {{:techtalk:ref:oil:sportster_oil_pressure_-_oil_pump_oil_migration_1977-1985_by_hippysmack.png?direct&400|}} ((drawing by Hippysmack)) {{:techtalk:ref:oil:sportster_oil_pressure_-_oil_pump_oil_migration_1986-1990_by_hippysmack.png?direct&400|}} ((drawing by Hippysmack)) \\
 +
  
 ===== System Pressure Loss From Internal Leakage (recirculating oil) ===== ===== System Pressure Loss From Internal Leakage (recirculating oil) =====
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 However, the efficiency of positive displacement pumps increases as the pressure increases. \\ However, the efficiency of positive displacement pumps increases as the pressure increases. \\
 At low RPM, the percentage of slip in relation to volumetric displacement is higher than at high speed. ((https://www.pumpindustry.com.au/pump-school-when-to-use-a-positive-displacement-pump/)) \\ At low RPM, the percentage of slip in relation to volumetric displacement is higher than at high speed. ((https://www.pumpindustry.com.au/pump-school-when-to-use-a-positive-displacement-pump/)) \\
 +
 ==== Affects of Viscosity ==== ==== Affects of Viscosity ====
 As mentioned above, there is always a certain amount of internal leakage in a pump that is within clearance range. \\ As mentioned above, there is always a certain amount of internal leakage in a pump that is within clearance range. \\
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   * **Scratches on gerotor riding surfaces**: \\ The surface in the housing or cover where the gerotors ride can get scratched from grit or debris traveling with the oil. \\ Debris caught between the teeth rotate across the dividers between the inlet and outlet cavities gouging the divider(s). \\ This has been noticed more on the larger divider pad although scratches do appear on both dividers (especially 1977-1990 oil pumps). \\ This has also been noted more on the return gerotors than the feed side. \\ Broken motor internals go thru the return side first, then the oil tank. \\ Heavier pieces fall below the feed outlet in the oil tank. \\ So for bits of motor internals to get to the feed side to score it up, they first had to travel to the retrun side, possibly scoring that up initially. \\ The feed gerotors are open across the large pad and it's easier to trap debris between the inner and outer teeth while dragging it across the pad. \\ Minor scratches can be from grit in the oil being dragged across the pads when gotten under the gerotors. \\ So there could be multiple scratches with multiple causes over time on the divider pads in the oil pump. \\ The gerotors are designed to ride against flat surfaces. Scratches in the riding surfaces can allow oil to recirculate (outlet to inlet). \\ This will lower the amount of flow that goes to the engine by however much oil can make it through the scratches. \\ This can also lower static pressure on the feed side especially on sustained idle or lower RPM if the scratches are deep enough. \\ \\ 1977-1990 Sportster oil pumps will have more of a tendency for deeper scratches in the cover than later oil pumps. \\ This is due to the two divider spacers (1 each on feed and return gerotor facing each other) with a spring washer between them. \\ The spring washer will allow the gerotors to jerk down or up on impact. \\ There is a space between the plates that separates feed and return gerotors held away from each other with the spring washer. \\ Debris caught between gerotor teeth can cause the gerotors to jump up/down allowing debris to get under them. \\ This allows larger debris to be dragged through both the large and small cavity divider plates leaving deeper scratches on pump cover. \\ \\ How much pressure loss would depend on the width, depth, length of the scratches, oil viscosity at the time and engine RPM. \\ Idle / Low RPM will allow the most leakage (recirculation). \\ Higher RPM brings higher pressure to the outlet side and more pressure drop toward the inlet side = less internal oil leakage. \\ Hot oil flows faster than cooler oil. Higher heat lowers viscosity even more. \\ As viscosity lowers, oil flows faster, especially at idle. \\ Deep scratches will recirculate more oil than shallow ones. \\ Deep scratches recirculate more oil on high RPM than shallow ones.      * **Scratches on gerotor riding surfaces**: \\ The surface in the housing or cover where the gerotors ride can get scratched from grit or debris traveling with the oil. \\ Debris caught between the teeth rotate across the dividers between the inlet and outlet cavities gouging the divider(s). \\ This has been noticed more on the larger divider pad although scratches do appear on both dividers (especially 1977-1990 oil pumps). \\ This has also been noted more on the return gerotors than the feed side. \\ Broken motor internals go thru the return side first, then the oil tank. \\ Heavier pieces fall below the feed outlet in the oil tank. \\ So for bits of motor internals to get to the feed side to score it up, they first had to travel to the retrun side, possibly scoring that up initially. \\ The feed gerotors are open across the large pad and it's easier to trap debris between the inner and outer teeth while dragging it across the pad. \\ Minor scratches can be from grit in the oil being dragged across the pads when gotten under the gerotors. \\ So there could be multiple scratches with multiple causes over time on the divider pads in the oil pump. \\ The gerotors are designed to ride against flat surfaces. Scratches in the riding surfaces can allow oil to recirculate (outlet to inlet). \\ This will lower the amount of flow that goes to the engine by however much oil can make it through the scratches. \\ This can also lower static pressure on the feed side especially on sustained idle or lower RPM if the scratches are deep enough. \\ \\ 1977-1990 Sportster oil pumps will have more of a tendency for deeper scratches in the cover than later oil pumps. \\ This is due to the two divider spacers (1 each on feed and return gerotor facing each other) with a spring washer between them. \\ The spring washer will allow the gerotors to jerk down or up on impact. \\ There is a space between the plates that separates feed and return gerotors held away from each other with the spring washer. \\ Debris caught between gerotor teeth can cause the gerotors to jump up/down allowing debris to get under them. \\ This allows larger debris to be dragged through both the large and small cavity divider plates leaving deeper scratches on pump cover. \\ \\ How much pressure loss would depend on the width, depth, length of the scratches, oil viscosity at the time and engine RPM. \\ Idle / Low RPM will allow the most leakage (recirculation). \\ Higher RPM brings higher pressure to the outlet side and more pressure drop toward the inlet side = less internal oil leakage. \\ Hot oil flows faster than cooler oil. Higher heat lowers viscosity even more. \\ As viscosity lowers, oil flows faster, especially at idle. \\ Deep scratches will recirculate more oil than shallow ones. \\ Deep scratches recirculate more oil on high RPM than shallow ones.   
  
-|Metal chunk lodged in return inlet. \\ The one medium scratch on big pad is some concern. \\ Small amount of recirculation oil internally. \\ Metal debris lessens amount of pickup oil at once.  \\ May be reusable with further observation ((photo by sc72 of the XLFORUM http://xlforum.net/forums/showthread.php?t=1717592&page=15))|Deep and wide channel ripped into big pad. \\ Light scratches across small pad. \\ High possibility of recirculating oil internally, \\ (feed outlet to feed inlet thru big pad scratch) \\ Owner said oil was not returning. \\ Should be replaced. ((photo by Rolli of the XLFORUM http://xlforum.net/forums/showthread.php?p=5877838&highlight=oil+pump#post5877838))|A gearshaft pin sheared and got into the return cavity. \\ It broke out a corner of the big pad. \\ The remaining flat surface of pad is undamaged. \\ Should be reusable with further observation. ((photo by DirtyCory of the XLFORUM http://xlforum.net/forums/showthread.php?t=1297584&page=2))|+|Metal chunk lodged in return inlet. \\ The one medium scratch on big pad is some concern. \\ Small amount of recirculation oil internally. \\ Metal debris lessens amount of pickup oil at once.  \\ May be reusable with further observation ((photo by sc72 of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/ironhead-sportster-motorcycle-talk-1957-1985/160106-where-to-go-from-here/page15?t=1717592&page=15))|Deep and wide channel ripped into big pad. \\ Light scratches across small pad. \\ High possibility of recirculating oil internally, \\ (feed outlet to feed inlet thru big pad scratch) \\ Owner said oil was not returning. \\ Should be replaced. ((photo by Rolli of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/ironhead-sportster-motorcycle-talk-1957-1985/201663-1983-ironhead-oil-not-returning?highlight=oil+pump#post4475667))|A gearshaft pin sheared and got into the return cavity. \\ It broke out a corner of the big pad. \\ The remaining flat surface of pad is undamaged. \\ Should be reusable with further observation. ((photo by DirtyCory of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/ironhead-sportster-motorcycle-talk-1957-1985/127032-getting-this-78-back-to-the-way-it-should-be/page2?t=1297584&page=2))|
 |{{: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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 Friction in the feed passages creates higher static (gauge) pressure. The higher the flow rate, the higher the affects from friction. \\ Friction in the feed passages creates higher static (gauge) pressure. The higher the flow rate, the higher the affects from friction. \\
 See below. \\ See below. \\
 +
 ====== Friction Loss ====== ====== Friction Loss ======
 Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. ((https://byjus.com/physics/fluid-friction/)) \\ Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. ((https://byjus.com/physics/fluid-friction/)) \\
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 Meanwhile, the inside of the motor is creating higher temps. \\ Meanwhile, the inside of the motor is creating higher temps. \\
 The oil reacts to the temp of it's surroundings (metal around it heats up, oil heats up because of it). \\ The oil reacts to the temp of it's surroundings (metal around it heats up, oil heats up because of it). \\
-So if the heat coming off the motor is blown away from it, that keeps the that heat from staying close to the motor and reaching even higher temps. \\+So if the heat coming off the motor is blown away from it, that keeps the heat from staying close to the motor and reaching even higher temps. \\
 It also keeps the oil inside from reaching higher temps but air while riding down the road doesn't actually cool the oil. \\ It also keeps the oil inside from reaching higher temps but air while riding down the road doesn't actually cool the oil. \\
 The oil inside the motor doesn't directly receive the benefit of outside air flow. \\ The oil inside the motor doesn't directly receive the benefit of outside air flow. \\
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 |  Pic of recirculation zone ((photo by Hippysmack))  |  Video showing recirculation zone ((video by Hippysmack))  | |  Pic of recirculation zone ((photo by Hippysmack))  |  Video showing recirculation zone ((video by Hippysmack))  |
-|{{:techtalk:ref:oil:sportster_oil_pressure_-_orifice_3_vena_contracta_by_hippysmack.jpg?direct&400|}} ((photo by Hippysmack))|{{:video:oil_pump_flow_testing_video-_recirculation_past_an_orifice_by_hippysmack.mp4|}} ((video by Hippysmack))|+|{{:techtalk:ref:oil:sportster_oil_pressure_-_orifice_3_vena_contracta_by_hippysmack.jpg?direct&400|}} ((photo by Hippysmack))|{{video:100-oil_pump_flow_testing_-_recirculation_past_an_orifice_by_hippysmack.mp4|}} ((video by Hippysmack))|
 ====== Flow Rates ====== ====== Flow Rates ======
 Velocity through a line can be calculated with the formula: Velocity (FPS) = (GPM x 0.3208) ÷ Area Velocity through a line can be calculated with the formula: Velocity (FPS) = (GPM x 0.3208) ÷ Area
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 ===== Flow Rate Chart for Water ===== ===== Flow Rate Chart for Water =====
 These figures are for water through orifices and do not represent oil flow through orifices. \\ These figures are for water through orifices and do not represent oil flow through orifices. \\
-Oil flow at operating temp will be differnet due to oil having a higher viscosity. \\+Oil flow at operating temp will be different due to oil having a higher viscosity. \\
 Water is basically regarded as having no viscosity. \\ Water is basically regarded as having no viscosity. \\
 The chart below is a reprint from Senninger.com. ((https://www.senninger.com/sites/senninger.hunterindustries.com/files/nozzle-flow-sheet.pdf)) \\ The chart below is a reprint from Senninger.com. ((https://www.senninger.com/sites/senninger.hunterindustries.com/files/nozzle-flow-sheet.pdf)) \\
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 Either of these, done properly, will effectively block the discharge from happening. \\ Either of these, done properly, will effectively block the discharge from happening. \\
  
-{{:techtalk:ref:oil:86-90_oil_filter_pad_mod_3_by_joergen.jpg?direct&300|}} ((photo by Jorgen of the XLFORUM http://xlforum.net/forums/showthread.php?t=1619616&highlight=jorgen+oil+pump&page=42)) \\+{{:techtalk:ref:oil:86-90_oil_filter_pad_mod_3_by_joergen.jpg?direct&300|}} ((photo by Jorgen of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-motor-engine/sportster-motorcycle-engine-conversions/149281-124-1993-xlh-build-thread/page42?t=1619616&highlight=jorgen+oil+pump&page=42)) \\
  
 So what is the trade-off of doing this mod? \\ So what is the trade-off of doing this mod? \\

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