With injectors and pumps being at the tight tolerances coming off the manufactures floor, then taking a used oil that has been so called strained or filtered crude at best (coffee filter), through the injectors and pumps possibly scratching them or damaging them beyond repair and performance levels, I don't really think this is a good idea. Please don't missunderstand me, I know people have done it and used the so called filtered oil, but then people jump off of the Golden Gate Bridge also without a parachute. Just my .02