In preparation for trying to restart the motor in my 1984 318i, which hasn’t been run in 8+ years, I pull the lower oil pan to clean out the sludge, etc. I was surprised to find a Febi branded oil pump as I don’t remember it ever being replaced (although there has been an extra oil pump sprocket in the trunk for decades). I am the only owner of the car. So my question is does anyone know who was the BMW OEM of M10 oil pumps at the time. Before I bother to take the pump apart, are the internals, i.e. springs, plunger, etc. the same/interchangeable?