Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Both sides previous revision Previous revision
Next revision
Previous revision
techtalk:ih:engmech07 [2019/10/11 23:40]
hippysmack [Breather Valve Alternatives]
techtalk:ih:engmech07 [2019/12/04 04:30] (current)
hippysmack [Sub Documents]
Line 86: Line 86:
 Documents from HD Racing from the period show no HP gain between the 2 systems when the breather is properly timed ( which didn't happen a lot). \\ Documents from HD Racing from the period show no HP gain between the 2 systems when the breather is properly timed ( which didn't happen a lot). \\
 ===== 76< Timed Breather Valve ===== ===== 76< Timed Breather Valve =====
-The rotary breather valve is timed to open on the downstroke of the pistons. ((1960 HD FSM pg 3a-15)) \\+==== Sub Documents ==== 
 +  * [[techtalk:​ih:​engmech07a|Timing the 76< Breather Valve]] 
 + 
 +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)) \\
Line 121: Line 131:
  
 |{{:​techtalk:​ih:​engmech:​cc_flow_6_by_dr_dick.jpg?​direct&​300|}}|{{:​techtalk:​ih:​engmech:​cc_flow_7_by_dr_dick.jpg?​direct&​300|}}|{{:​techtalk:​ih:​engmech:​cc_flow_8_by_dr_dick.jpg?​direct&​300|}}| |{{:​techtalk:​ih:​engmech:​cc_flow_6_by_dr_dick.jpg?​direct&​300|}}|{{:​techtalk:​ih:​engmech:​cc_flow_7_by_dr_dick.jpg?​direct&​300|}}|{{:​techtalk:​ih:​engmech:​cc_flow_8_by_dr_dick.jpg?​direct&​300|}}|
 +\\
  
 +There are only 3 rotor and tower slot widths for all 1937-76 4-cam engines (45, K, KH, XL, UL), which determine the complete breather timing interval. ((kitabel of the XLFORUM http://​xlforum.net/​forums/​showthread.php?​t=2073932&​page=87)) \\ 
 +  - Rotor .375" (88°) + tower .34375"​ (81°) = 169°: \\ all non-R 1937-71 engines; the exact opening-closing points vary between engines; 1952-71 K &c. slots are taller than 45 & UL. 
 +  - Rotor .594" (146°) + tower .34375"​ (81°) = 227°: 1972-76 XL; these slots are also taller than 45 & UL. 
 +  - Rotor .214" (99°) + tower .269 (125°) = 224°: all 1954-? KR, KHR, XLR (many mods to this)
  
 ===== 77-78 Breather Valve ===== ===== 77-78 Breather Valve =====