firstly why would a piston ring have anything to do with oil pressurem, all your piston rings do is keep the oil out the cylinder. Its your bottom end and obviously your oil pump that generate the pressure. secondly its prob just the sender unit had it on mine b4 i went for the defis 8) would tick over at 2 turn the car off fill up turn it back on and it wouldnt even register 1 that made my mind up that the sender had to go for something more accurate. ok so dont panic and no your compressions are ok well within the safe range