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techtalk:ref:oil15 [2019/06/13 02:12]
hippysmack [Rocker Box]
techtalk:ref:oil15 [2019/06/13 02:13]
hippysmack [Testing per the FSMs]
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 +
 +==== 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 ===== ===== 86 and Up models =====