The way my system is plumbed you are correct, the
oil to pressurize the system is drawn from the
oil pan. However, the
oil is forced through the oil filter before being delivered to the engine so metal is not a problem. I agree that unfiltered oil should not be pumped into the engine and had the same concern until I studied the schematic. If you think about it, the oil route using the Preluber is the same as when drawn from the pan via the oil pump; pan -->oil pump -->oil cooler --> oil filter --> engine bearings. I run a Canton T-sump road race pan. There is a fitting on the side of the sump that I used for the preluber pickup. Therefore oil is sucked from approximately one inch up from the bottom of the pan, actually higher in the sump than the oil pump pickup is located (1/2" from the bottom). There is indeed a check valve in the Preluber unit that prevents reverse oil flow back to the pan. Unlike the Accusump, this powered system is great to use to pressurize the engine following an oil and filter change. Just turn the key to ON and allow the unit to build pressure. I have noted that following an oil and oil filter change on an engine with an oil cooler it does take several seconds to build oil pressure at the first start. Without this system the engine would have to be cranked and run without oil pressure for that several seconds until all the air is purged.
For those individuals concerned about loss of oil pressure during cornering, etc. this should never happen if the oil pickup screen was set up correctly to begin with and if there is a proper oil level on the dipstick. Since most of us run a mechanical oil presure gauge and might not be looking at it if and when the oil pressure suddenly drops to Zero, I offer the following suggestion: on the oil pressure gauge fitting on the side of the block install a 1/8 NPT T fitting to allow installation of both the mechanical capillary tube AND an electric sending unit. Plumb the sending unit to a red dash light and a buzzer. If the oil pressure takes a nose dive the light will illuminate and the buzzer will warn you immediately to kill the engine.