Differences

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--- techtalk:ref:oil15 [2019/06/13 02:10]
hippysmack [Between the oil pump and the filter (86-Up)]
+++ techtalk:ref:oil15 [2019/06/13 02:20]
hippysmack [Testing between the oil pump and the filter]
@@ Line 48: / Line 48: @@
 {{:techtalk:ref:oil:installing_an_oil_gauge_8_by_hippysmack.jpg?direct&300|}}
 {{:techtalk:ref:oil:installing_an_oil_gauge_9_by_hippysmack.jpg?direct&300|}} \\
+==== Testing at the rocker box ====
+A Sportster does produce oil pressure in the rocker box: reportedly 3-5 psi at hot idle and 15psi+ on cold startup on an ironhead. ((simeli of the XLFORUM http://xlforum.net/forums/showthread.php?t=263589&highlight=lower+oil+pump&page=4)) \\
+Depending on the gauge selected, there may be little to no oil pressure registered on a high range gauge testing form the rocker box. \\
+(the gauge may show some pressure when the oil is cool and thick but may not show any after 5 minutes of running) ((mycle1000 of the XLFORUM http://xlforum.net/forums/showthread.php?t=263589&highlight=lower+oil+pump&page=3)) \\
+Due to the low oil pressure at the rocker box, \\
+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.
+    * 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.
+    * Excess 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 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.
+    * As air will compress and oil will not, therefore the readings should be lower than if you were testing at the oil pressure switch.
 ===== 86 and Up models =====
@@ Line 68: / Line 86: @@
 {{:techtalk:ref:oil:installing_an_oil_gauge_3_by_hippysmack.jpg?direct&300|}}{{:techtalk:ref:oil:installing_an_oil_gauge_4_by_hippysmack.jpg?direct&300|}} \\
-==== Between the oil pump and the filter ====
+==== Testing at the rocker box ====
-and prior engines use an oil filter in the return side of the system after the oil exits the engine. \\
-So an oil pressure gauge between the pump and filter would not tell you much about the engine feed oil. \\
-In 1986, the oil pressure switch was moved to an external feed side oil filter. \\
+A Sportster does produce oil pressure in the rocker box. \\
-Future feed oil from Evo oil pumps comes out of the pump to the filter pad. \\
-Consequently it's not possible to block the pump outlet with a pressure gauge without starving the engine of oil. \\
-So installing a gauge on the oil pump fittings is not going to be very helpful. \\
-Also, installing a pressure gauge straight into a gauge will result in the pump building up enough pressure to destroy the gauge. \\
-However, it is possible to install gauge in the feed line from the pump to the filter pad using a tee fitting. \\
-That way, as the pressure builds, it will both enter the gauge and the flow into the engine. \\
-{{:techtalk:ref:oil:installing_an_oil_gauge_2_by_hippysmack.jpg?direct&300|}}
-{{:techtalk:ref:oil:installing_an_oil_gauge_6_by_hippysmack.jpg?direct&300|}}{{:techtalk:ref:oil:installing_an_oil_gauge_7_by_hippysmack.jpg?direct&300|}} \\
-==== Rocker Box ====
-A Sportster does produce oil pressure in the rocker box: reportedly 3-5 psi at hot idle and 15psi+ on cold startup on an ironhead. ((simeli of the XLFORUM http://xlforum.net/forums/showthread.php?t=263589&highlight=lower+oil+pump&page=4)) \\
 Depending on the gauge selected, there may be little to no oil pressure registered on a high range gauge testing form the rocker box. \\
 (the gauge may show some pressure when the oil is cool and thick but may not show any after 5 minutes of running) ((mycle1000 of the XLFORUM http://xlforum.net/forums/showthread.php?t=263589&highlight=lower+oil+pump&page=3)) \\
 Due to the low oil pressure at the rocker box, \\
 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.
@@ Line 103: / Line 103: @@
     * 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.
+    * Also oil ends up in the bottom of the rocker box to the head drains and air resides in the top of the box. \\
+==== Testing between the oil pump and the filter ====
+and prior engines use an oil filter in the return side of the system after the oil exits the engine. \\
+So an oil pressure gauge between the pump and filter would not tell you much about the engine feed oil. \\
+In 1986, the oil pressure switch was moved to an external feed side oil filter. \\
+Future feed oil from Evo oil pumps comes out of the pump to the filter pad. \\
+Consequently it's not possible to block the pump outlet with a pressure gauge without starving the engine of oil. \\
+So installing a gauge on the oil pump fittings is not going to be very helpful. \\
+Also, installing a pressure gauge straight into a gauge will result in the pump building up enough pressure to destroy the gauge. \\
+However, it is possible to install gauge in the feed line from the pump to the filter pad using a tee fitting. \\
+That way, as the pressure builds, it will both enter the gauge and the flow into the engine. \\
+{{:techtalk:ref:oil:installing_an_oil_gauge_2_by_hippysmack.jpg?direct&300|}}
+{{:techtalk:ref:oil:installing_an_oil_gauge_6_by_hippysmack.jpg?direct&300|}}{{:techtalk:ref:oil:installing_an_oil_gauge_7_by_hippysmack.jpg?direct&300|}} \\

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