Differences

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--- techtalk:ih:oil03p [2021/11/11 00:16]
hippysmack [77-85 Oil Pump Inspection]
+++ techtalk:ih:oil03p [2024/05/07 23:32] (current)
hippysmack [Inspect the oil pump cover and body]
@@ Line 2: / Line 2: @@
 ====== IH: Oiling & Lubrication - Sub-03P ======
 ====== 77-85 Oil Pump Inspection ======
 With the replacement of the gear driven oil pump by the new gerotor style pump; \\ HD issued a recommendation to dealers regarding servicing of the new style oil pumps. ((HD Service Bulletin #M-711 dated June 3, 1977)) \\ Zero gerotor (gear) side clearance must be maintained by the flat spring between the upper and lower separator plates for adequate oil pressure. \\ For the spring to function properly, the upper face of the lower feed gerotors must extend slightly above the cover to prevent any side clearance. \\ (which would allow oil to get past the gerotors and reduce oil pressure) \\ If you have reduced oil, no oil pressure (oil light comes on or stays on) or otherwise need to disassemble the oil pump for any reason, \\ The gerotors and their corresponding operating surface in the housing and the cover should be checked and serviced accordingly.
+**Before inspecting any of the parts, clean all the oil and debris from them first**. \\
+Cracks or otherwise damage are sometimes hard to see unless the parts are clean. \\
 ===== Inspect the oil pump cover and body =====
 === Look for debris while disassembling ===
 Grit / Debris found in the oil pump can give clues to potential motor problems. \\
 While removing each part starting from the cover, make note of the color of the oil, any grit or metal particles and what color they are. \\
@@ Line 19: / Line 20: @@
   * Which side of the pump is it in, feed or return?: \\ Debris in the return side came out of the motor into the pump. \\ Debris in the feed side came from the oil tank (which most likely came from the motor to the oil tank). \\ For long term diagnosis, this may not find a smoking gun problem. \\ But in cases of sudden failure, it may be an important clue as in where to start looking for problems.
   * Silicone should not be used anywhere on a Sportster motor. \\ If so, you may find pieces of it in the oil pump or in the small orifics and oil galleys within the motor. \\ The push / pull of crankcase pressure can implode gaskets and especially sealants like silicone. \\ This will stop up the oil paths in the motor and if caught early enough, can be flushed out before catastrophic damage happens.
-  * Visually inspect the inside of the check valve to make sure the little disc up inside it is fully closed. \\ Loose metal particles can get stuck between the disc and the valve body keeping the disc from closing. \\ If you find metal debris in the check valve, there may also be metal that made it's way past the check into the motor.
-|Silicone 'gummy bear' sheet found in the feed side|Oil check valve stuck open with metal debris ((photo by Screwloose of the XLFORUM http://xlforum.net/forums/showthread.php?t=1979566))|
+|Silicone 'gummy bear' sheet found in the feed side ((photo by (-_-) of the XLFORUM, annotated by Hippysmack https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/efi-sportster-motorcycle-talk-2007-and-up/198113-help-me-figure-out-weird-engine-braking/page3?t=2074835&page=3))|
-|{{:techtalk:evo:oil:oil_pump_damage_3_by_-_-_-_annotated.jpg?direct&300|}} ((photo by (-_-) of the XLFORUM, annotated by Hippysmack http://xlforum.net/forums/showthread.php?t=2074835&page=3))|{{:techtalk:ih:oil:1977-1985_oil_pump_check_valve_by_screwloose.jpg?direct&300|}}|
+|{{:techtalk:evo:oil:oil_pump_damage_3_by_-_-_-_annotated.jpg?direct&300|}}|
 === Inspect the ridge in the cover ===
       * 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.
@@ Line 31: / Line 30: @@
 === Inspect the gerotor surface for flatness in the oil pump cover and housing ===
 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. \\
@@ Line 39: / Line 37: @@
 === Inspect the gerotor surface in the cover and housing for deep scratches or gouges ===
 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 http://xlforum.net/forums/showthread.php?t=2071153&page=6)) \\
+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. \\
@@ Line 69: / Line 66: @@
 They'll both flow faster when hot. \\
-|  Gerotor rotation (cover shown) ((photos by Hippysmack http://xlforum.net/forums/showthread.php?t=2071153&page=6))  ||
+|  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:77-85_oil_pump_cover_9a_by_hippysmack.jpg?direct&300|}}|{{:techtalk:ih:oil:77-85_oil_pump_cover_10a_by_hippysmack.jpg?direct&300|}}|
@@ Line 75: / Line 72: @@
 === Classifying Scratches in Gerotor Surfaces  ===
 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: \\
@@ Line 88: / Line 93: @@
   * Elongated scratches in these pads allow a constant amount of generated pressure on the outlet side to squirt back to the inlet side of the pump. \\ This will lower the pressure to the extent of how deep the scratches are. \\ Deep scratches allow more oil pressure or oil flow to recirculate from the outlet back to the inlet within the oil pump. \\ This makes for less oil gauge pressure on the feed side as well as less oil flow to the motor. \\ This makes for less oil flow back to the oil tank.
   * How many scratches or how deep the scratches need to be before the pump housing/cover needs to be replaced has never been publicized by the MoCo. \\ They apparently didn't want to get into the weeds... as I've done here.
-  * Backpressure is greater on the feed side than it is the return side. \\ The feed path from the pump has many turns and restrictions that build pressure. \\ Since oil is not compressible, it can't absorb any of that pressure. \\ So excess pressure is sent backwards from the restrictions. \\ This is how oil can recirculate form the feed outlet back to the feed inlet through out of service clearances and oil pump pad wear. \\ When the pressure is reverted backward, it runs back to the inlet side of the pump. \\ If backpressure is allowed to constantly run back to the inlet side, it will send oil back up the feed hose. \\ If you normally would have say 4psi at idle on the pump outlet, you'd now have 2 psi on the outlet and 2 psi going back to the inlet.
+  * Backpressure is greater on the feed side than it is the return side. \\ The feed path from the pump has many turns and restrictions that build pressure. \\ Since oil is not compressible, it can't absorb any of that pressure. \\ So excess pressure is sent backwards from the restrictions. \\ This is how oil can recirculate from the feed outlet back to the feed inlet through out of service clearances and oil pump pad wear. \\ When the pressure is reverted backward, it runs back to the inlet side of the pump. \\ If backpressure is allowed to constantly run back to the inlet side, it will send oil back up the feed hose. \\ If you normally would have say 4psi at idle on the pump outlet, you'd now have 2 psi on the outlet and 2 psi going back to the inlet.
   * Consequently, more oil will recirculate thru the feed side than the return side if both big pads have identical width and depth elongated scratches. \\ The backpressure from the feed side would push more oil faster under the gerotors than the return side with less backpressure. \\ If the oil tank vent line is stopped up, backpressure on the return side of the pump will be greater and send more oil under the gerotors back to the sump.
   * I'd guesstimate that there are a whole lot of Sportsters on the road with motors having gerotor pumps with various degrees of scratches. \\ The fact that there hasn't been a lot of talk on degrees of scratches in the oil pump says that most probably don't worry too much about them. \\ But then, you end up seeing that one complete teardown due to an oil pump problem and you get to wondering yourself.
@@ Line 99: / Line 104: @@
 Any marked reusable should still be pressure tested and observed if you'll be using them. \\
-|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|}}|
 === Check for cracks in the housing and cover ===
 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. \\
-|  Repair on oil pump cover ((photos by acb2 of the XLFORUM http://xlforum.net/forums/showthread.php?t=554323))  ||  Oil Switch Torque ((drawing by Hippysmack))  |
+|  Repair on oil pump cover ((photos by acb2 of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/ironhead-sportster-motorcycle-talk-1957-1985/77330-oil-pump-1977-up?t=554323))  ||  Oil Switch Torque ((drawing by Hippysmack))  |
 |{{: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|}}|
 === Inspect the Housing Roll Pin ===
 The roll pin is installed into the "shelf" between the housing bores and it normally shouldn't see any shear force. \\
-All internals depend on the strength of the solid pins, and the drive gear. \\
+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 outer separator plate has a slot in it that installs over the roll pin. \\
+The scavenge gerotor is not quite as tall as the "shelf" where the inner plate sits. \\
+Normally, there is a slight gap between the return gerotor set and the inner plate. Inner plate sits against the shelf, not the return gerotors. \\
+When you button up the pump and the spring washer tightens the turning of the gearshaft, it's tightening against the feed gerotors, not return. \\
+So the return side should be free to move up and down with RPM and float off the plate. \\
+The separator (divider) plates have a slot on their OD that installs over the roll pin. \\
 Normally the only force on the roll pin is stationary pressure from the outer plate wanting to turn with the feed gerotor under it. \\
-However, sudden jolts or back pressure on the pump can strengthen that stationary pressure against the roll pin and either pull it out or shear it off. \\
+However, sudden jolts or back pressure on the pump can strengthen that stationary pressure against the roll pin. \\
+The roll pin in the oil pump housing can be damaged (by the parts in the pump getting in a bind) or by a previous hamfisted pump assembly. \\
+The pin can be punished by the divider plates enough to wallow the hole it's in and/or damaging the hole enough to loosen the pin. \\
+This may be due to foreign matter in the feed or return cavities. \\
+Any foreign objects that enter the pump can increase the pressure against the plates to move. \\
+Or the pin can be damaged from simply trying to remove it. \\
+The hole in the center of the divider plates is off center. The roll pin locates the plates to the housing and the off centered drive shaft. \\
+**Check the roll pin**. \\
 Give the roll pin a slight tug with needle nose pliers to make sure it is good and pressed in and doesn't want to wiggle. \\
 If there is any looseness or wiggle, pull it out and replace it now so you don't find it inside the motor later. \\
+There is nothing wrong with the roll pin in this photo. \\
 {{:techtalk:ih:oil:77-85_oil_pump_body_7_by_hippysmack.jpg?direct&300|}} ((photo by Hippysmack)) \\
+\\
+\\
-===== Inspect the gearshaft and bushings for damage or wear =====
+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 needed, below are some possible ways to remove the roll pin**. \\
+  - You can try a side dike wire cutter and a little electrical freeze spray on the aluminum.
+  - You could try running a small tap into the roll pin to cut threads for a small screw, then screw the bolt into the center. \\ Once the bolt hits bottom of the hole, it may push the pin up and out or at least loosen the pin. ((Andy Hog 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))
+  - You may or may not need to cut the buggered part off, but you could try to fill the pin with oil and insert a close fitting punch into the hole. The hit the punch with a hammer. The hammer blow may move the pin upward. ((sungod 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))
+  - This is tedious but would work, if done properly and with a steady hand. \\ This method may also be used if the existing hole is broken out or the is wallowed to where a new pin would not tighten up to the existing hole. You could carefully cut the old pin flush with a Dremil tool, leave the old pin where it is and install a new pin elsewhere. Note: if you drill a new pin hole you must cut new slots in the 2 plates that the pin locates. ((needspeed 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/page2)) You can't rotate the plates into a different position because the hole in the plates that the shaft goes through is not exactly in the middle (off centered).
+    * First, remove the guts inside and install both divider plates over the old pin to locate them properly. Then drill a small hole (smaller than the pin hole) thru the top plate, thru to the bottom plate and stop when it is dimpled by the drill bit. Remove the plates and finish drilling the second plate. Then use a Dremil tool or file to cut a slot from edge of plate to hole (on ea plate)
+    * Reinstall both plates and drill thru the new slots in both to make a dimple in the pump housing, remove plates.
+    * Drill hole in pump housing to depth of new pin (correct bore size for new pin). \\ It's good to have an index drill bit set (especially for smaller bits). Most drill bits will wallow a hole bigger than what it is written on the bit. Start with a slightly smaller bit than (projected installed OD of the pin dia) into the plates and just enough into the housing to make a dot. Then pull it back apart and square up the housing using the same drill bit. Measure it and drill with bigger bit if needed for the pin. If you drill too wide, the pin won't stay. Roll pins are sized by the dia of the hole needed (1/8" roll pin for 1/8" hole) but the pin will measure bigger than that. Just need to make sure the hole doesn't wallow.
+    * 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.
+**Generally bad ideas for removing the pin**.
+  * 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.
+**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)) \\
+{{:techtalk:ih:oil:1977-e1983_sportster_oil_pump_roll_pin_removal_pic1_by_billeuze.jpg?direct&400|}} {{:techtalk:ih:oil:1977-e1983_sportster_oil_pump_roll_pin_removal_pic2_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|}} \\
+===== Inspect the gearshaft and bushings for damage or wear =====
     * Check the gearshaft teeth for pits, breakage or wear. Replace the gearshaft as necessary. \\ Also do not forget to check the teeth on the oil pump drive gear on the pinion shaft. \\ If the teeth on it are thin, replace the drive gear. \\ Pinion shaft runout can wear the drive gear teeth down thin enough to break off and float with the oil.
     * Clean areas where the shaft sits in a bushing with steel wool if needed. \\ If it's not possible to smooth the areas out, replace the shaft.
@@ Line 142: / Line 189: @@
 ===== Gerotor shear pins =====
   * The solid shear pins in the gearshaft may be different lengths and/or different OD. \\ There is no spec for the pins in the service manual.
   * The pins main function is to turn the gerotors. \\ Pin construction is designed to be the weak point and let go if the pump gets jammed with solid objects. \\ (like bits of metal etc in the gears, or if the oil pump bushings seize etc).
-  * Just putting a new shear pin back in without fully rebuilding the pump and checking for jamming or seizing is begging for the same thing to happen again. ((Hopper of the XLFORUM http://xlforum.net/forums/showthread.php?p=1232889))
+  * Just putting a new shear pin back in without fully rebuilding the pump and checking for jamming or seizing is begging for the same thing to happen again. ((Hopper of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/ironhead-sportster-motorcycle-talk-1957-1985/49875-heeeeeeeeeeelpppp-meeeeeeeeee-motor-dying-in-4th-gear/page2#post1049264))
   * The gerotors are much taller than the pin thickness.
   * So the height of the slot allows a fudge factor on quick throttle blips and the gerotors won't be affected. \\ The gearshaft will rise some on higher throttle and there is built in "up and down" clearance in the pump to allow this. \\
-  * The pins are not pressed into the gearshaft and the holes in the gearshaft for the pins are different depths on several used gearshafts inspected. \\ Knowing this, it makes sense to be aware that the holes in the shaft can wallow out or the loose fit of the pins can wear the pins faster. \\ You can buy a handful of new pins only to find they are all different dims as well. \\ If you find real slop in the pin fit to the pins, either replace the pins and/or the gearshaft. \\ Do not buy hardened pins as that will defeat the purpose of the "shear pin" design. If the pins only protrude slightly into the gerotor slots, use longer pins. \\
+  * The pins are not pressed into the gearshaft and the holes in the gearshaft for the pins are different depths on several used gearshafts inspected. \\ Knowing this, it makes sense to be aware that the holes in the shaft can wallow out or the loose fit of the pins can wear the pins faster. \\ You can buy a handful of new pins only to find they are all different dims as well. \\ If you find real slop in the pin fit to the gearshaft, either replace the pins and/or the gearshaft. \\ Do not buy hardened pins as that will defeat the purpose of the "shear pin" design. If the pins only protrude slightly into the gerotor slots, use longer pins. \\
 The pics below are used parts but show the pin locations and how they look installed with a gerotor on the shaft. \\
@@ Line 154: / Line 200: @@
 {{:techtalk:ih:oil:1977-1985_oil_pump_gearshaft_pins_by_hippysmack.jpg?direct&300|}} {{:techtalk:ih:oil:77-85_oil_pump_gearshaft_pin_location_3_by_hippysmack.jpg?direct&300|}} {{:techtalk:ih:oil:77-85_oil_pump_gearshaft_pin_location_5_by_hippysmack.jpg?direct&300|}} \\
 ===== Inspect both gerotor sets =====
-Clean both gerotor sets with solvent, brake cleaner et., and inspect them closely for cracks. \\
+Clean both gerotor sets with solvent, brake cleaner etc. \\
+\\
+**Inspect inner and outer pieces of both gerotor sets closely for cracks (most cracks are going to run vertically)**. \\
 It may be hard to see cracks from a distance or when the gerotors are oily / dirty. \\
-The outer return piece below was cracked but not all the way through. Being cracked at all is still a problem (could result in lower oil pressure). \\
+Cracks can happen when debris gets pinned between the inner and outer gerotors. \\
-Replace any gerotors with damaged teeth, nicks or cracks. The problem will only get worse. \\
+As they spin around and pinch something between them, the offending item tries to bind or lock up the gerotors while the geasrshaft still wants to spin. \\
-{{:techtalk:ih:oil:1983l-1985_outer_gerotor-_cracked_by_attaxic.jpg?direct&300|}} ((photo by Attaxic of the XLFORUM http://xlforum.net/forums/showthread.php?t=2078758&page=4)) \\
+Technically, the solid shear pins on the gearshaft should also be checked for damage if you find a cracked gerotor. \\
+The pins should shear before that much pressure is put on the gerotors. \\
+If aftermarket hardened pins are used instead of OEM pins, they could hold up and not shear which transfers gearshaft energy to the gerotors instead. \\
+This is another example of parts designed to fail before others down line do. \\
+(L - below) The outer return piece below was cracked but not all the way through. Being cracked at all is still a problem (could result in lower oil pressure). \\
+Replace any gerotors with damaged teeth, nicks or cracks. \\
+The problem will only get worse (gerotor will break into pieces) and oil pressure will be lower until the gerotor breaks. \\
+(R - below) The inner feed gerotor broke into 4 separate pieces starting from the slot in the gerotor where the gearshaft pin catches it. \\
+{{:techtalk:ih:oil:1983l-1985_outer_gerotor-_cracked_by_attaxic.jpg?direct&300|}} ((photo by Attaxic 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/page4?t=2078758&page=4)) {{:techtalk:ih:oil:1977-1985_inner_feed_gerotor_broken_by_freewheeler.jpg?direct&300|}} ((photo by Freewheeler of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/ironhead-sportster-motorcycle-talk-1957-1985/174337-homebrew-ironhead-sheared-oil-pump-pin?threadid=1869407)) \\
 \\
 **Check inner to outer gerotor clearance on each gerotor set**. \\
 Each gerotor set is made with an inner and outer piece. Mesh the two pieces together (as they normally would sit in operation). \\
+This clearance has a direct relationship to oil pump flow and oil pressure. \\
+The wider the clearance the more the gerotors lose their ability to hold enough pressure to the outlet cavity. \\
+They also the ability to transfer oil from the feed cavity back to the inlet cavity and recirculate oil within the oil pump. \\
   * Arrange so there is 1 inner tooth facing the center of the wide outer radius. \\ Use a feeler gauge between the inner tooth and outer radius there for a maximum of .004" clearance between them. \\ If the clearance is larger than .004", replace the affected gearotor set. Repeat for the other gerotor set.
 {{:techtalk:ih:oil:1977-1985_oil_pump_gerotors_-_checking_clearance_by_hippysmack.jpg?direct&300|}} ((photo by Hippysmack)) \\
 \\
-  * Measure the height of each inner and outer gerotor set. \\ Each inner and outer piece (feed side) should be the same height, each inner and outer (return side) should be the same height. \\ Replace gerotors as a set respectively if the inner and outer pieces are not the same height. \\ A micrometer will reveal tighter measurements rather than the caliper used below. \\ However, there are so many small variances in these pumps that less than .001" increments isn't going to be the hill to trash your pump on. \\
+  * **Measure the height of each inner and outer gerotor set**. \\ Each inner and outer piece (feed side) should be the same height, each inner and outer (return side) should be the same height. \\ Replace gerotors as a set respectively if the inner and outer pieces are not the same height. \\ A micrometer will reveal tighter measurements rather than the caliper used below. \\ However, there are so many small variances in these pumps that less than .001" increments isn't going to be the hill to trash your pump on. \\
 {{:techtalk:ih:oil:77-85_gerotor-_measuring_feed_set_height_by_hippysmack.jpg?direct&300|}} ((photo by Hippysmack)) {{:techtalk:ih:oil:77-85_gerotor-_measuring_return_set_height_by_hippysmack.jpg?direct&300|}} ((photo by Hippysmack)) \\
 ===== Inspect the Seals and O-rings =====
 It's never a bad idea to replace seals and O-rings every time you go into the oil pump. \\
@@ Line 186: / Line 249: @@
 {{:techtalk:ih:oil:1977-1985_oil_check_valve_assembly_pic_1_by_hippysmack.jpg?direct&300|}} ((photo by Hippysmack)) {{:techtalk:ih:oil:12036_and_12036a_outer_plate_seals.jpg?direct&300|}} ((photo by Hippysmack)) \\
 ===== Inspect the oil check valve =====
 [[techtalk:ih:oil01#oil_pump_check_valve|Click Here]] to read more about the oil pump check valve in the Sportsterpedia. \\
     *  Make sure it's not clogged and the internal spring closes the cup / disc properly. \\ The spring loaded cup inside the valve should be free to move and should return to it's closed, seated position. \\ It the check valve is damaged in any way, the complete valve assembly should be replaced. \\ There are no replaceable parts to it.
+    * Loose metal particles can get stuck between the disc and the valve body keeping the disc from closing. \\ If you find metal debris in the check valve, there may also be metal that made it's way past the check into the motor.
-{{:techtalk:ih:oil:77-85_oil_check_valve_1_by_hippysmack.jpg?direct&300|}} ((photo by Hippysmack)) {{:techtalk:ih:oil:77-85_oil_check_valve_drawing_by_hippysmack.jpg?direct&300|}} ((photo by Hippysmack)) \\
+(R) below, the check valve was stuck open with metal debris. \\
-===== Inspect the spring washer =====
+{{:techtalk:ih:oil:77-85_oil_check_valve_1_by_hippysmack.jpg?direct&300|}} ((photo by Hippysmack)) {{:techtalk:ih:oil:77-85_oil_check_valve_drawing_by_hippysmack.jpg?direct&300|}} ((photo by Hippysmack)) {{:techtalk:ih:oil:1977-1985_oil_pump_check_valve_by_screwloose.jpg?direct&300|}} ((photo by Screwloose of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-era-specific-and-model-specific/ironhead-sportster-motorcycle-talk-1957-1985/184257-oil-pump-porn?t=1979566)) \\
+===== Inspect the spring washer =====
 The spring resides between the separator plates (between the feed and scavenge gerotors) and is supposed to keep pressure against both plates. \\
 The inner plate stops at the housing bore "shelf" and doesn't push against the return gerotors. \\