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techtalk:ref:oil20 [2022/06/08 16:21] hippysmack [Crankcase Pressure / Venting the Oil Tank] |
techtalk:ref:oil20 [2022/09/10 02:52] hippysmack [Oil Tank Pressure] |
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| ====== REF: Oiling & Lubrication ====== | ====== REF: Oiling & Lubrication ====== | ||
| ====== Oil Tank Pressure ====== | ====== Oil Tank Pressure ====== | ||
| + | See also, [[techtalk:ref:oil21#oil_tank_head_pressure|Oil Tank Head Pressure]] in the Sportsterpedia. \\ | ||
| There should not be any noticeable pressure in the oil tank due to the generated pressure being vented back into the cam chest. ((Hippysmack of the XLFORUM http://xlforum.net/forums/showthread.php?p=5736179#post5736179)) \\ | There should not be any noticeable pressure in the oil tank due to the generated pressure being vented back into the cam chest. ((Hippysmack of the XLFORUM http://xlforum.net/forums/showthread.php?p=5736179#post5736179)) \\ | ||
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| ====== Crankcase Pressure / Venting the Oil Tank ====== | ====== Crankcase Pressure / Venting the Oil Tank ====== | ||
| - | **Venting the oil tank**: \\ | + | ==== Air Pressure and Oil Level ==== |
| - | The oil tank is by design, vented to the cam chest and out the engine breather vent(s). | + | |
| - | Neither the oil cap nor the oil tank should be vented without a one way check valve. \\ | + | |
| - | The tank is vented to the cam chest on purpose to remove condensate (that gets pumped in) from the oil tank out the single one way engine breather valve. \\ | + | |
| - | Venting the oil tank \ cap also will negatively influence crankcase pressure by letting in extra air. \\ | + | |
| - | 1/2 of the return flow is air because the return pump is twice as big as the feed pump. ((ryder rick of the XLFORUM http://xlforum.net/forums/showthread.php?t=1904589&page=4)) \\ | + | |
| - | That air is full of condensate. A slightly negative (to atmospheric) pressure in the tank facilitates vaporization of the condensate. \\ | + | |
| - | **Air pressure and oil level**. \\ | ||
| Air inside the tank doesn't get there because of CC pressure alone. Ambient air resides in the upper portion of the tank above the oil level. \\ | Air inside the tank doesn't get there because of CC pressure alone. Ambient air resides in the upper portion of the tank above the oil level. \\ | ||
| The air was there first. Then the oil was added. If you add too much oil, there will be even less air in the tank. \\ | The air was there first. Then the oil was added. If you add too much oil, there will be even less air in the tank. \\ | ||
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| {{:techtalk:ref:oil:oil_pressure_drawing_1_by_hippysmack.jpg?direct&450|}} ((drawing by Hippysmack)) {{:techtalk:ref:oil:oil_pressure_drawing_4_by_hippysmack.jpg?direct&450|}} ((drawing by Hippysmack)) | {{:techtalk:ref:oil:oil_pressure_drawing_1_by_hippysmack.jpg?direct&450|}} ((drawing by Hippysmack)) {{:techtalk:ref:oil:oil_pressure_drawing_4_by_hippysmack.jpg?direct&450|}} ((drawing by Hippysmack)) | ||
| + | \\ | ||
| Since it's not the oil pump scavenger's job to separate the oil/air mist, both crankcase pressure and oil end up in the oil tank. ((Hippysmack of the XLFORUM http://xlforum.net/forums/showthread.php?p=5736179#post5736179)) \\ | Since it's not the oil pump scavenger's job to separate the oil/air mist, both crankcase pressure and oil end up in the oil tank. ((Hippysmack of the XLFORUM http://xlforum.net/forums/showthread.php?p=5736179#post5736179)) \\ | ||
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| {{:techtalk:ref:oil:oil_pressure_drawing_2_by_hippysmack.jpg?direct&450|}} ((drawing by Hippysmack)) | {{:techtalk:ref:oil:oil_pressure_drawing_2_by_hippysmack.jpg?direct&450|}} ((drawing by Hippysmack)) | ||
| {{:techtalk:ref:oil:oil_pressure_drawing_3_by_hippysmack.jpg?direct&450|}} ((drawing by Hippysmack)) | {{:techtalk:ref:oil:oil_pressure_drawing_3_by_hippysmack.jpg?direct&450|}} ((drawing by Hippysmack)) | ||
| + | \\ | ||
| The piston movements in the HD engine are not in apposing positions to balance out the displacement of air. \\ | The piston movements in the HD engine are not in apposing positions to balance out the displacement of air. \\ | ||
| They are mounted on the same crank pin and oscillate into a small volume crankcase. \\ | They are mounted on the same crank pin and oscillate into a small volume crankcase. \\ | ||
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| See more here [[techtalk:ref:engmech04|Evo Crankcase Pressure]] on engine breathing, crankcase pressure and blowby in the REF section of the Sportsterpedia. \\ | See more here [[techtalk:ref:engmech04|Evo Crankcase Pressure]] on engine breathing, crankcase pressure and blowby in the REF section of the Sportsterpedia. \\ | ||
| - | **If the oil tank vent line is plugged up**, the oil pump will still send air/oil pressure into the tank. \\ | + | ==== Stopped Up Vent Line ==== |
| + | If the oil tank vent line is plugged up, the oil pump will still send air/oil pressure into the tank. \\ | ||
| The air pressure can't leave the tank but the oil is recirculated from the tank into the engine by the feed side of the pump. \\ | The air pressure can't leave the tank but the oil is recirculated from the tank into the engine by the feed side of the pump. \\ | ||
| Pressure will build in the tank until the cap blows, oil leaks from the cap or the oil tank splits (plastic). \\ | Pressure will build in the tank until the cap blows, oil leaks from the cap or the oil tank splits (plastic). \\ | ||
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| And that can lead to wetsumping with more oil in the sump than usual. \\ | And that can lead to wetsumping with more oil in the sump than usual. \\ | ||
| - | **Removing the oil cap with the engine running**. \\ | + | ==== Removing the Oil Cap with the Engine Running ==== |
| Removing the oil cap on a hot idling engine (so far rigid S models only), may lower engine speed if the breather valve(s) aren't working properly. ((Hippysmack of the XLFORUM http://xlforum.net/forums/showthread.php?p=5763694#post5763694)) \\ | Removing the oil cap on a hot idling engine (so far rigid S models only), may lower engine speed if the breather valve(s) aren't working properly. ((Hippysmack of the XLFORUM http://xlforum.net/forums/showthread.php?p=5763694#post5763694)) \\ | ||
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| Read more on [[techtalk:ref:engmech04#fluid_drag|Fluid Drag]] above. \\ | Read more on [[techtalk:ref:engmech04#fluid_drag|Fluid Drag]] above. \\ | ||
| - | **2004-Present Sportsters use the oil pump and oil tank to expel most of the crankcase air into the cam chest**. \\ | ||
| - | Some goes out the pinion shaft bearing clearances but the only other outlet for piston downstroke air is the oil pump. \\ | ||
| - | The source of air intake to the crankcase on piston upstroke is the pinion shaft bearing clearance. \\ | ||
| - | The oil pump is steadily pushing oil and air out of the crankcase into the oil tank. \\ | ||
| + | ==== Venting the Oil Tank ==== | ||
| + | |||
| + | The oil tank is by design, vented to the cam chest and out the engine breather vent(s). | ||
| + | Neither the oil cap nor the oil tank should be vented without a one way check valve. \\ | ||
| + | The tank is vented to the cam chest on purpose to remove condensate (that gets pumped in) from the oil tank out the single one way engine breather valve. \\ | ||
| + | Venting the oil tank \ cap also will negatively influence crankcase pressure by letting in extra air. \\ | ||
| + | 1/2 of the return flow is air because the return pump is twice as big as the feed pump. ((ryder rick of the XLFORUM http://xlforum.net/forums/showthread.php?t=1904589&page=4)) \\ | ||
| + | That air is full of condensate. A slightly negative (to atmospheric) pressure in the tank facilitates vaporization of the condensate. \\ | ||
| + | |||
| + | * **1977-2003 Sportsters use oil pump scavenge and the oil tank to remove __some__ of the crankcase air into the cam chest**. \\ However, there are also holes in the cam walls for crankcase air to escape into the cam chest and head drains to the crankcase. \\ These holes carry crankcase air out to the cam chest without using the oil pump. \\ The oil pump does still have bigger feed gerotors that will pick up crankcase air to the oil pump also. \\ But the crankcase is not bottled up like 2004-up motors. | ||
| + | |||
| + | * **2004-Present Sportsters use oil pump scavenge and the oil tank to move __most__ of the crankcase air into the cam chest**. \\ Some goes out the pinion shaft bearing clearances but the only other outlet for piston downstroke air is the oil pump. \\ The source of air intake to the crankcase on piston upstroke is the pinion shaft bearing clearance. \\ The oil pump is steadily pushing oil and air out of the crankcase into the oil tank and then into the cam chest / rocker boxes to the head vents. | ||
| + | |||
| + | 1977-2003 Venting: \\ | ||
| + | {{:techtalk:ref:oil:1998-2003_sportster_oil_tank_oem_crankcase_pressure_2_to_tank_by_hippysmack.png?direct&400|}} ((drawing by Hippysmack)) {{:techtalk:ref:oil:1998-2003_sportster_oil_tank_vented_crankcase_pressure_to_tank_by_hippysmack.png?direct&400|}} ((drawing by Hippysmack)) \\ | ||
| + | |||
| + | 2004-up Venting: \\ | ||
| {{:techtalk:ref:oil:2004-2006_sportster_oil_tank_oem_crankcase_pressure_to_tank_by_hippysmack.png?direct&400|}} ((drawing by Hippysmack)) {{:techtalk:ref:oil:2004-2006_sportster_oil_tank_vented_crankcase_pressure_to_tank_by_hippysmack.png?direct&400|}} ((drawing by Hippysmack)) \\ | {{:techtalk:ref:oil:2004-2006_sportster_oil_tank_oem_crankcase_pressure_to_tank_by_hippysmack.png?direct&400|}} ((drawing by Hippysmack)) {{:techtalk:ref:oil:2004-2006_sportster_oil_tank_vented_crankcase_pressure_to_tank_by_hippysmack.png?direct&400|}} ((drawing by Hippysmack)) \\ | ||
