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techtalk:ih:engmech07 [2019/12/04 00:52] hippysmack [Sub Documents] |
techtalk:ih:engmech07 [2019/12/04 04:30] hippysmack [Sub Documents] |
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* [[techtalk:ih:engmech07a|Timing the 76< Breather Valve]] | * [[techtalk:ih:engmech07a|Timing the 76< Breather Valve]] | ||
- | The rotary breather valve is timed to open on the downstroke of the pistons. ((1960 HD FSM pg 3a-15)) \\ | + | The rotary breather valve functions to relieve pressure in the crankcase caused by the downstroke of the pistons and it controls the flow of oil in the lubrication system. \\ |
+ | It is timed to open on the downstroke of the pistons. ((1960 HD FSM pg 3a-15)) \\ | ||
This allows crankcase exhaust air pressure to expel the scavenge oil from the crankcase breather oil trap into the gearcase. \\ | This allows crankcase exhaust air pressure to expel the scavenge oil from the crankcase breather oil trap into the gearcase. \\ | ||
- | The breather valve closes on piston upstroke, creating vacuum in the crankcase. \\ | + | The breather valve then closes on piston upstroke, creating vacuum in the crankcase. \\ |
+ | Crankcase exhaust air from the gearcase is sent out the breather tube. \\ | ||
+ | Any oil still in suspension with the air on the way to the breather tube is separated by an oil slinger on the generator drive gear. \\ | ||
+ | |||
+ | A street oil pump has 2 slots and is driven at 1/2 engine speed. ((thefrenchowl of the XLFORUM http://xlforum.net/forums/showthread.php?t=448751)) \\ | ||
+ | A racing oil pump has 4 slots and is driven at 1/4 engine speed. \\ | ||
+ | All 4 stroke engines takes two revolutions before you come back to the timing marks being all aligned. | ||
How the volume compares when the breather opens as to when it closes: ((Dr Dick of the XLFORUM http://xlforum.net/forums/showthread.php?t=1204854&page=3)) \\ | How the volume compares when the breather opens as to when it closes: ((Dr Dick of the XLFORUM http://xlforum.net/forums/showthread.php?t=1204854&page=3)) \\ |