My $2,300 series 2A a shop let out the door with no oil in the engine; I got it to run but doubt the oil flow to the head so I haven't been driving it except to the barn and back once in a while but yesterday I drove it about 3 miles, I shouldn't have because if the rpm gets very high you can hear it knocking but before the engine gets warm and while there is plenty of oil pressure it's ok to drive to the neighbors, like a quarter mile one way.
before i made it back home the oil press was about zero and a massive amount of oil was running out the clutch housing. I can still start it and move it around the 'yard' but it's just gonna have to wait till i get to it. I can only hope the crank and block are still ok.
It's nicer to drive than my series 3.