Differences
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techtalk:ref:oil15 [2019/06/13 02:20] hippysmack [Testing between the oil pump and the filter] |
techtalk:ref:oil15 [2019/06/13 02:28] hippysmack [Testing at the rocker box] |
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| Don't get scared when you look down after its hot and its on zero. ((vyper202 of the XLFORUM http://xlforum.net/forums/showthread.php?t=1698960)) \\ | Don't get scared when you look down after its hot and its on zero. ((vyper202 of the XLFORUM http://xlforum.net/forums/showthread.php?t=1698960)) \\ | ||
| - | * Residual crankcase pressure and working pressure from the lifters resides in the rocker boxes. | + | * Residual crankcase pressure and working pressure from the oiling tubes resides in the rocker boxes. |
| * On a cold startup, the pressure is higher due to the thicker oil present. | * On a cold startup, the pressure is higher due to the thicker oil present. | ||
| * As the engine warms up, the oil thins out and the pressure is reduced in the rocker boxes. | * As the engine warms up, the oil thins out and the pressure is reduced in the rocker boxes. | ||
| - | * Excess crankcase pressure (air and oil mist) is vented differently between pre and post 91 engines. | + | * Pulsating crankcase pressure (air and oil mist) resides over the entire breathing system as well as the rocker boxes. \\ (even though the crankcase pressure is vented through the cam cover). |
| - | * On pre 91 engines, excess crankcase pressure is vented through the cam cover. | + | * So, it is possible to notice different pressures with a pressure gauge testing from the rocker box. |
| - | * On post 91 engines, excess crankcase pressure is routed up the pushrod tubes and vented thru the rocker boxes to exit a hole in each head. | + | |
| - | * So, it is possible to notice different pressures from them with a pressure gauge testing from the rocker box. | + | |
| * However, a gauge tapped into any rocker box will most likely measure air pressure instead of oil pressure. | * However, a gauge tapped into any rocker box will most likely measure air pressure instead of oil pressure. | ||
| * As air will compress and oil will not, therefore the readings should be lower than if you were testing at the oil pressure switch. | * As air will compress and oil will not, therefore the readings should be lower than if you were testing at the oil pressure switch. | ||
| + | * Also oil ends up in the bottom of the rocker box to the head drains and air resides in the top of the box. | ||
| ===== 86 and Up models ===== | ===== 86 and Up models ===== | ||
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| * On a cold startup, the pressure is higher due to the thicker oil present. | * On a cold startup, the pressure is higher due to the thicker oil present. | ||
| * As the engine warms up, the oil thins out and the pressure is reduced in the rocker boxes. | * As the engine warms up, the oil thins out and the pressure is reduced in the rocker boxes. | ||
| - | * Excess crankcase pressure (air and oil mist) is vented differently between pre and post 91 engines. | + | * Pulsating crankcase pressure (air and oil mist) is vented differently between pre and post 91 engines. |
| * On pre 91 engines, excess crankcase pressure is vented through the cam cover. | * On pre 91 engines, excess crankcase pressure is vented through the cam cover. | ||
| * On post 91 engines, excess crankcase pressure is routed up the pushrod tubes and vented thru the rocker boxes to exit a hole in each head. | * On post 91 engines, excess crankcase pressure is routed up the pushrod tubes and vented thru the rocker boxes to exit a hole in each head. | ||
