Differences
This shows you the differences between two versions of the page.
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techtalk:ref:engmech04l [2020/10/04 22:17] hippysmack created |
techtalk:ref:engmech04l [2023/12/22 15:03] (current) hippysmack |
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| It will create more backpressure inside the engine until a stronger force is applied from inside. \\ | It will create more backpressure inside the engine until a stronger force is applied from inside. \\ | ||
| That stronger force would be the air created on downstroke. In a perfect world, the downstroke won't be impeded so the force won't slow down. \\ | That stronger force would be the air created on downstroke. In a perfect world, the downstroke won't be impeded so the force won't slow down. \\ | ||
| - | The higher positive pressure assists in oil scavenging (the pressure inside builds a little more from that restriction). ((Hippysmack of the XLFORUM http://xlforum.net/forums/showthread.php?t=2073932&page=9)) \\ | + | The higher positive pressure assists in oil scavenging (the pressure inside builds a little more from that restriction). ((Hippysmack of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-motor-engine/sportster-motorcycle-bottom-end/197307-sportster-crankcase-pressure-engine-breathing-wetsumping-and-mods/page9?t=2073932&page=9)) \\ |
| But it only bottles up pressure on downstroke and only to a point. That little more positive pressure is an extra push on the lower end toward the sump scavenge port. \\ | But it only bottles up pressure on downstroke and only to a point. That little more positive pressure is an extra push on the lower end toward the sump scavenge port. \\ | ||
| Another result would be air moving out at a faster rate thru the smaller hole. The smaller hole creates higher pressure. Higher pressure equates to faster flow. \\ | Another result would be air moving out at a faster rate thru the smaller hole. The smaller hole creates higher pressure. Higher pressure equates to faster flow. \\ | ||
| - | {{:techtalk:evo:carb:91-03_breather_bolts_1_by_hippysmack.jpg?direct&300|}} ((photo by Hippysmack)) {{:techtalk:evo:engmech:04_up_breather_bolt_2_by_folkie.jpg?direct&300|}} ((photo by Folkie of the XLFORUM http://xlforum.net/forums/showthread.php?p=5756327#post5756327)) {{:techtalk:evo:engmech:04_up_breather_bolt_1_by_folkie.jpg?direct&300|}} ((photo by Folkie of the XLFORUM http://xlforum.net/forums/showthread.php?p=5756327#post5756327)) \\ | + | {{:techtalk:evo:carb:91-03_breather_bolts_1_by_hippysmack.jpg?direct&300|}} ((photo by Hippysmack)) {{:techtalk:evo:engmech:04_up_breather_bolt_2_by_folkie.jpg?direct&300|}} ((photo by Folkie of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-intake-and-exhaust/sportster-motorcycle-air-intake-carburetor-efi-fuel-and-exhaust/28874-stock-air-cleaner-box-modifications/page20#post4310316)) {{:techtalk:evo:engmech:04_up_breather_bolt_1_by_folkie.jpg?direct&300|}} ((photo by Folkie of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-intake-and-exhaust/sportster-motorcycle-air-intake-carburetor-efi-fuel-and-exhaust/28874-stock-air-cleaner-box-modifications/page20#post4310316)) \\ |
| ==== Head Drainage ==== | ==== Head Drainage ==== | ||
| The debated question on head breathing systems is; \\ | The debated question on head breathing systems is; \\ | ||
| - | When the engine is running at high speed, is there any kind of pressure being created that might slow down the drainage from the top? ((NRHS Sales of the XLFORUM http://xlforum.net/forums/showthread.php?t=53769&highlight=valve+guide&page=31)) \\ | + | When the engine is running at high speed, is there any kind of pressure being created that might slow down the drainage from the top? ((NRHS Sales of the XLFORUM https://www.xlforum.net/forum/vendors/nrhs-high-performance/32415-oil-usage-and-timing/page31?t=53769&highlight=valve+guide&page=31)) \\ |
| - | The oil feed to the top end is pressurized and the return is gravity fed. ((jrclark19 of the XLFORUM http://xlforum.net/forums/showthread.php?t=53769&highlight=valve+guide&page=31)) \\ | + | The oil feed to the top end is pressurized and the return is gravity fed. ((jrclark19 of the XLFORUM https://www.xlforum.net/forum/vendors/nrhs-high-performance/32415-oil-usage-and-timing/page31?t=53769&highlight=valve+guide&page=31)) \\ |
| The drain for the top end is at least 2-3 times larger than the hole in the pushrods. \\ | The drain for the top end is at least 2-3 times larger than the hole in the pushrods. \\ | ||
| - | It's been said that CC pressure moving up the pushrod tubes interferes with drain oil traveling down the tubes. ((Hippysmack of the XLFORUM http://xlforum.net/forums/showthread.php?t=2073932&page=2)) \\ | + | It's been said that CC pressure moving up the pushrod tubes interferes with drain oil traveling down the tubes. ((Hippysmack of the XLFORUM https://www.xlforum.net/forum/sportster-motorcycle-forum/sportster-motorcycle-motor-engine/sportster-motorcycle-bottom-end/197307-sportster-crankcase-pressure-engine-breathing-wetsumping-and-mods/page2?t=2073932&page=2)) \\ |
| However, drain oil mainly goes into the head / cylinder drain holes from the rocker arms spraying the valves. \\ | However, drain oil mainly goes into the head / cylinder drain holes from the rocker arms spraying the valves. \\ | ||
| And liquid oil is much heavier than air moving up the passage. \\ | And liquid oil is much heavier than air moving up the passage. \\ | ||
| Line 52: | Line 52: | ||
| ==== Testing the Head Drains ==== | ==== Testing the Head Drains ==== | ||
| - | Test performed by cjburr of the XLFORUM ((http://xlforum.net/forums/showthread.php?t=53769&highlight=valve+guide&page=31)) \\ | + | Test performed by cjburr of the XLFORUM ((https://www.xlforum.net/forum/vendors/nrhs-high-performance/32415-oil-usage-and-timing/page31?t=53769&highlight=valve+guide&page=31)) \\ |
| //Disclaimer: \\ | //Disclaimer: \\ | ||
| Line 78: | Line 78: | ||
| Oil was introduced into the head with a with a turkey baster. \\ | Oil was introduced into the head with a with a turkey baster. \\ | ||
| (which is probably a higher volume of oil than it normally sees from the splash oiling) \\ | (which is probably a higher volume of oil than it normally sees from the splash oiling) \\ | ||
| - | However, if the drains were plugged, oil would overfill to the point of spewing oil at the seams and submerge the seals. ((cjburr of the XLFORUM http://xlforum.net/forums/showthread.php?t=53769&highlight=valve+guide&page=33)) \\ | + | However, if the drains were plugged, oil would overfill to the point of spewing oil at the seams and submerge the seals. ((cjburr of the XLFORUM https://www.xlforum.net/forum/vendors/nrhs-high-performance/32415-oil-usage-and-timing/page33?t=53769&highlight=valve+guide&page=33)) \\ |
| - | | Head ready for testing. ((photo by cjburr of the XLFORUM http://xlforum.net/forums/showthread.php?t=53769&highlight=valve+guide&page=31)) | Oil poured in and draining. ((photo by cjburr of the XLFORUM http://xlforum.net/forums/showthread.php?t=53769&highlight=valve+guide&page=31)) |Oil level at the intake valve when it starts to drain to \\ the exhaust side. ((photo by cjburr of the XLFORUM http://xlforum.net/forums/showthread.php?t=53769&highlight=valve+guide&page=31)) | | + | | Head ready for testing. ((photo by cjburr of the XLFORUM https://www.xlforum.net/forum/vendors/nrhs-high-performance/32415-oil-usage-and-timing/page31?t=53769&highlight=valve+guide&page=31)) | Oil poured in and draining. ((photo by cjburr of the XLFORUM https://www.xlforum.net/forum/vendors/nrhs-high-performance/32415-oil-usage-and-timing/page31?t=53769&highlight=valve+guide&page=31)) |Oil level at the intake valve when it starts to drain to \\ the exhaust side. ((photo by cjburr of the XLFORUM https://www.xlforum.net/forum/vendors/nrhs-high-performance/32415-oil-usage-and-timing/page31?t=53769&highlight=valve+guide&page=31)) | |
| |{{:techtalk:ref:engmech:head_drainage_test_1_by_cjburr.jpg?direct&300|}}|{{:techtalk:ref:engmech:head_drainage_test_2_by_cjburr.jpg?direct&300|}}|{{:techtalk:ref:engmech:head_drainage_test_3_by_cjburr.jpg?direct&300|}}| | |{{:techtalk:ref:engmech:head_drainage_test_1_by_cjburr.jpg?direct&300|}}|{{:techtalk:ref:engmech:head_drainage_test_2_by_cjburr.jpg?direct&300|}}|{{:techtalk:ref:engmech:head_drainage_test_3_by_cjburr.jpg?direct&300|}}| | ||
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| But it may not be necessary as it does drain really well and the spring seat above it might negate any advantage you got from doing so. \\ | But it may not be necessary as it does drain really well and the spring seat above it might negate any advantage you got from doing so. \\ | ||
| - | |Oil level at the exhaust valve when draining stops. ((photo by cjburr of the XLFORUM http://xlforum.net/forums/showthread.php?t=53769&highlight=valve+guide&page=31)) | This is as high as the level got at the intake valve. ((photo by cjburr of the XLFORUM http://xlforum.net/forums/showthread.php?t=53769&highlight=valve+guide&page=31)) | This is the drain in the exhaust pocket. ((photo by cjburr of the XLFORUM http://xlforum.net/forums/showthread.php?t=53769&highlight=valve+guide&page=31)) | | + | |Oil level at the exhaust valve when draining stops. ((photo by cjburr of the XLFORUM https://www.xlforum.net/forum/vendors/nrhs-high-performance/32415-oil-usage-and-timing/page31?t=53769&highlight=valve+guide&page=31)) | This is as high as the level got at the intake valve. ((photo by cjburr of the XLFORUM https://www.xlforum.net/forum/vendors/nrhs-high-performance/32415-oil-usage-and-timing/page31?t=53769&highlight=valve+guide&page=31)) | This is the drain in the exhaust pocket. ((photo by cjburr of the XLFORUM https://www.xlforum.net/forum/vendors/nrhs-high-performance/32415-oil-usage-and-timing/page31?t=53769&highlight=valve+guide&page=31)) | |
| |{{:techtalk:ref:engmech:head_drainage_test_4_by_cjburr.jpg?direct&300|}}|{{:techtalk:ref:engmech:head_drainage_test_5_by_cjburr.jpg?direct&300|}}|{{:techtalk:ref:engmech:head_drainage_test_6_by_cjburr.jpg?direct&300|}}| | |{{:techtalk:ref:engmech:head_drainage_test_4_by_cjburr.jpg?direct&300|}}|{{:techtalk:ref:engmech:head_drainage_test_5_by_cjburr.jpg?direct&300|}}|{{:techtalk:ref:engmech:head_drainage_test_6_by_cjburr.jpg?direct&300|}}| | ||
