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techtalk:ref:engmech04a [2019/08/05 00:55] hippysmack [Dissecting the Hayden KVP38 Crankcase Breather Valve] |
techtalk:ref:engmech04a [2024/01/14 21:47] (current) hippysmack |
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| - | The parts of the "Background" information in the patent material are shown in italics below. \\ | + | In preamble, the Hayden crankcase breather valve is of good quality. \\ |
| - | Comments on this information is shown in bold below. ((Hippysmack of the XLFORUM http://xlforum.net/forums/showthread.php?t=2073932&page=39)) \\ | + | Most that have tried it are satisfied with it's operation. \\ |
| + | The foregoing is to clarify it's operation as it relates to Sportster engine breathing. \\ | ||
| + | The umbrella valve that it uses is the same umbrella that [[https://www.jamesgaskets.com/product/jgi-26856-89/|James Gaskets sells for all 1991-1999, Evolution® & Sportster® models]]. \\ | ||
| + | For that reason, it doesn't seem to be the umbrella that is the 'improvement' (same umbrella that James sells to many, many Sportsters). \\ | ||
| + | The 'improvements' appear to be machined ramps to and from the umbrella, the spacer and the shimming of the umbrella. \\ | ||
| - | //A crankcase breather valve for ventilation and pressure control within the crankcase of an internal combustion engine in which pistons stroke upwardly and downwardly in a synchronous movement. The valve is inserted into a breather hose which conducts gases into and out of the crankcase. The valve comprises a resilient valve member, preferably an elastomeric umbrella-type seal, spaced above a seal seat and forming a gap there between through which gases may flow either direction during portions of the pistons' stroke cycle. The valve construction permits three operating modes: firstly to permit the egress of positive pressure gas out of the crankcase and through the gap while the pistons stroke downwardly; secondly, to permit the ingress of a small amount of gas back through the gap into the crankcase when the crankcase pressure changes from positive to negative; and thirdly to check further ingress of gas into the crankcase at greater crankcase suctions, developed when the piston's are moving upwardly.// | ||
| + | The segments of the "Background" information in the patent material are shown in italics below. \\ | ||
| + | Comments on this information is shown in bold below. ((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/page39?t=2073932&page=39)) \\ | ||
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| + | {{:techtalk:ref:engmech:hayden_breather_valve_drawing_by_hippysmack.jpg?direct&300|}} ((drawing by Hippysmack)) | ||
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| + | //A crankcase breather valve for ventilation and pressure control within the crankcase of an internal combustion engine in which pistons stroke upwardly and downwardly in a synchronous movement. The valve is inserted into a breather hose which conducts gases into and out of the crankcase. The valve comprises a resilient valve member, preferably an elastomeric umbrella-type seal, spaced above a seal seat and forming a gap there between through which gases may flow either direction during portions of the pistons' stroke cycle. The valve construction permits three operating modes: firstly to permit the egress of positive pressure gas out of the crankcase and through the gap while the pistons stroke downwardly; secondly, to permit the ingress of a small amount of gas back through the gap into the crankcase when the crankcase pressure changes from positive to negative; and thirdly to check further ingress of gas into the crankcase at greater crankcase suctions, developed when the piston's are moving upwardly.// | ||
| **The breather valve has 3 functions**. \\ | **The breather valve has 3 functions**. \\ | ||
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| **The gear driven breather's last year was 1978. \\ | **The gear driven breather's last year was 1978. \\ | ||
| - | They left out the '79 style internal reed valve. \\ | + | They left out the '79 style internal reed valve and the fact that Sportsters lost the timed breather in '77. \\ |
| - | They are representing ironhead technology up to 1992. \\ | + | They are representing ironhead technology up to 1992 (not true for Sportsters). \\ |
| They also cite excessive suction in the oil tank and lack of an oil head at the scavenge port in the sump as being sensitive to crankcase pressure. \\ | They also cite excessive suction in the oil tank and lack of an oil head at the scavenge port in the sump as being sensitive to crankcase pressure. \\ | ||
| Some points of interest:** \\ | Some points of interest:** \\ | ||
| Line 38: | Line 47: | ||
| * **Vacuum in the air above is pulled from above, not below and the oil in the tank is much heavier than the air above.** \\ | * **Vacuum in the air above is pulled from above, not below and the oil in the tank is much heavier than the air above.** \\ | ||
| * **Crankcase pressure cannot suck oil from the tank unless it's already been compromised by other means. \\ (worn or defective OEM breather valve)** | * **Crankcase pressure cannot suck oil from the tank unless it's already been compromised by other means. \\ (worn or defective OEM breather valve)** | ||
| - | * **The patent is suggesting that too much vacuum (negative pressure) can cavitate the oil pump.** | + | * **The patent is suggesting that too much vacuum (negative pressure) can cavitate the oil pump.** \\ This is true. |
| - | * **It also says the OEM umbrella is normally closed. But it isn't sealed and we do know they do let air back into the crankcase.** | + | * **It also says the OEM umbrella is normally closed**. \\ But it isn't sealed all the time (transients) and we do know they do let a slight amount of air back into the crankcase. \\ This helps to equalize mean pressure somewhat. |
| * **According to the patent information, the drain hole in the breather valve system has a dual purpose.** | * **According to the patent information, the drain hole in the breather valve system has a dual purpose.** | ||
| - **It drains oil that gets past the umbrella.** | - **It drains oil that gets past the umbrella.** | ||
| Line 76: | Line 85: | ||
| The Hayden assembly shims the James umbrella to prevent that movement and to adjust the air gap around it. \\ | The Hayden assembly shims the James umbrella to prevent that movement and to adjust the air gap around it. \\ | ||
| ** | ** | ||
| - | **It's the same umbrella that James sells for all 1991-1999, Evolution® & Sportster® models. https://www.jamesgaskets.com/product/jgi-26856-89/ \\ | ||
| - | For that reason, it doesn't seem to be the umbrella that is the 'improvement'. \\ | ||
| - | Same umbrella that James sells to many, many Sportsters. \\ | ||
| - | The 'improvements' appear to be machined ramps to and from the umbrella, the spacer and the shimming of the umbrella.** \\ | ||
| //Various modifications are apparent to those skilled in the art. For instance, variances in the materials of manufacture of the valve head will clearly affect the gap used. Further, use of a reed-type valve, spaced above a seal seat and being enclosed within a housing, can be seen to provide an equivalent valve in these instances.// | //Various modifications are apparent to those skilled in the art. For instance, variances in the materials of manufacture of the valve head will clearly affect the gap used. Further, use of a reed-type valve, spaced above a seal seat and being enclosed within a housing, can be seen to provide an equivalent valve in these instances.// | ||
