SHOtimer:
Scott, I assume the K&N part number is the breather valve that goes into the oil fill hole? thanx again for the help
Doug
The oiling system is designed to pump 5\30 oil thru metered orfices at at normal operating pressures, If the pressure is raised from using a heavier weight oil it will pump at less volume. So.... do you want more oil or less oil?
That was the panel K&N filter part number for your air filter as a direct replacement for the existing air filter. Sorry about the confusion. I recommend that you
do not install an externally vented breather on your engine due to what the Ford technician incorrectly stated about high crankcase pressure. Simply, he was wrong.
The oil pump in the SHO engine, and most internal combustion engines, is a positive displacement pump (PDP) that will pump a given volume of oil for each revolution of the engine crankshaft. It doesn't really care what the viscosity of the pumped fluid is, it will always pump the same volume per revolution. The higher pressure/lower volume relationship holds for cetrifugal pump designs, not PDPs.
Heavier weight oil? Do you mean the base stock? Because at operating temperatures, the 5W-30 and 10W-30 should both be performing as 30W oils. The benefit to the lower base weight oil is easier starting in cold (very cold) temperatures. The Ford users manual for the SHO states that the 10W-30 is good down to 0F (as in zero degrees Fahrenheit).
I don't believe that there are any metering orifices in the SHO's oil path. The system pressure is created and maintained by the clearances in the many bearings that the oil is forced into. It is when these clearances increase due to excessive wear that the oil pressure light illuminates due to low pressure in the system.
If there were a metering orifice downstream of the pump's output, it would just make the pump work harder and the pressure upstream of the orifice be quite high because, please remember, the pump is a positive displacement pump. It will always pump the same volume of any fluid per each revolution of the engine's crankshaft. I hope this clears up a few things.