Differences
This shows you the differences between two versions of the page.
| Both sides previous revisionPrevious revisionNext revision | Previous revision | ||
| techtalk:ih:oil03g [2024/09/24 02:32] – [Pump Body Damage] hippysmack | techtalk:ih:oil03g [2024/09/26 20:39] (current) – [Idler Shaft Removal] hippysmack | ||
|---|---|---|---|
| Line 297: | Line 297: | ||
| This makes questionable imperfections more to a higher degree of scrutiny than 77-up gerotor pumps that don't require engine uprooting. \\ | This makes questionable imperfections more to a higher degree of scrutiny than 77-up gerotor pumps that don't require engine uprooting. \\ | ||
| - | Scratches in and around the gear pockets are not neccessarily a huge problem unless they are too frequent or too deep. \\ | ||
| - | How frequent or how deep are the real questions. Answers may generally be vague or not detailed enough. \\ | ||
| - | The pump will output the volume of oil that it picks up between the teeth. \\ | ||
| - | The clearance between the gear teeth and the pump wall creates a hydraulic seal, locking the oil in the voids between the teeth. \\ | ||
| - | That hydraulic seal is made with a total clearance of .003" or less. That means .0015" MAX between each tooth and the side wall of the pump. \\ | ||
| - | Anything deeper than will break the hydraulic seal. \\ | ||
| - | This means some of that oil in the voids will get pulled into the voids and get slung back out as the gears rotate forward. \\ | ||
| - | And some will circulate around to the pressure side only to recirculate toward the suction side of the pump. \\ | ||
| - | The remainder of oil in the voids will be sent out the pressure side into the engine. \\ | ||
| - | Long short is the deeper the radial scratches are in the pump bore walls, the less pressure and flow you'll get to the motor. \\ | ||
| - | |||
| - | What causes the scratches? \\ | ||
| - | Oil is not just oil over the course of time. \\ | ||
| - | It normally picks up gas from the top end falling into the bottom end, tiny metal debris from the moving parts in the motor and condensation. \\ | ||
| - | These may produce light striations or scratches between the gear teeth and their corresponding pump walls in a circular motion. \\ | ||
| - | It picks up bigger debris/bits when damage is or was happening inside the motor from the moving parts. These make bigger scratches. \\ | ||
| - | |||
| - | Pics of oil pump bodies can be deceiving as really good cameras will make colorations/ | ||
| - | The only sure way at times is by cleaning the body with brake cleaner etc and eyeballing the areas in question. \\ | ||
| - | It's difficult to get any measuring equpiment in there. You could press some clay into the gear bore and remove it to measure scratch depth with a caliper. \\ | ||
| - | Machining marks are not a problem at all. Light scoring isn't really a problem either. \\ | ||
| - | It takes deeper scratches on the bore walls to harshly impact the flow. \\ | ||
| - | Multiple deeper scratching will only increase the amount of oil that will recirculate from the pressure side to the suction side. | ||
| - | |||
| - | This is the condition in question, recirculating oil in the pump dimenishes the amount of oil pumped to the motor. \\ | ||
| - | But that has to a lot of recirculating oil in order for the pump to not pump oil. \\ | ||
| - | Example, there was a pump that was put back together with mis-matched return gears (height difference app .070" | ||
| - | The pump was not pumping enough oil out of the motor. \\ | ||
| - | It still delivered oil to the tank but with a weak stream and oil was backing up in the cam chest. \\ | ||
| - | So just because there was oil coming into the tank didn't mean it was pumping enough oil. \\ | ||
| - | Deep multiple circular scratches in the body gear bore will under perform oil flow in the same way. \\ | ||
| Below is a compilation of just a few oil pumps with various gear well damage. \\ | Below is a compilation of just a few oil pumps with various gear well damage. \\ | ||
| Line 341: | Line 310: | ||
| ====== Idler Shaft Removal ====== | ====== Idler Shaft Removal ====== | ||
| - | If the idler shaft is damaged, you can remove it by applying heat to the pump body and the shaft should fall out. \\ | + | If the idler shaft is damaged, you can remove it by applying heat (150°F) |
| - | Then press in a new shaft making sure it is set even on both sides of the pump. | + | Heat the pump body to (150°F) to install idler gear shaft. Shaft may not protrude above either oil pump body face. ((1972-2003 XR-750 Service Manual)) \\ |
| \\ | \\ | ||
