"Old one just did not have good pressure after oil was warmed up."
Oil pressure is actually a misnomer. What you're reading on your oil gauge, if you've diagnosed this problem with an oil gauge - is actually how quick oil bleeds through the clearances in your engine. Tighter clearances, the higher your oil gauge reads. That's why it reads less when the engine's warmed up. When it's cold, the fitment is tighter and the gauge reads higher. When you put in thicker oil...the gauge reads higher.
The pressure side of the pump works the same all the time. When there's backpressure from the system it bleeds off into the camchest. The scavenger pump returns it to the oil bag. When your gauge starts reading lower it means you're still getting the same amount of flow - it just doesn't read as high of a number on the gauge. Believe me, if you had low oil pressure...your lifters would sound like solids.
Now you have all these clearances and you've installed a spanky new pump that's pumping oil like the engine was new. You've increased the flow...and now your breather valve is spitting it through the screen creating a higher mist than you had before. I'm also assuming you didn't enlarge the breather hole to accomodate the 25% increase in engine cubic inches, either.
While you're at it - check your return line, let's make sure you haven't sheered a scavenger key. Change the oil, pull the return line at the bag and point it into a clear jar and fire your ride up, see what kind of return you have. Bypass any external oil filter you've installed. See if the oil is too-bubbly, or worse, frothy. If it is...your camchest is overwhelmed with too much oil. If you're getting just a dribble...you've sheered a scavenger key.
I'd also be suspect of the "aftermarket" oil pump not being correct.
By: 47Knuckle-Dragger on: 4-14-2009
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