Patrick, you don't need the cooler on that motor you have. The radiator is going to to your water system plenty cool enough that the
oil will never get that hot.
By the way, the reason your
oil temp is running around 50c is because you are measuring that temperature out of the pan. The blowby air is keeping it cooler because the
oil gets stuck near the sender and gets cooled. Most likely the oil temp sensor is on a splitter with the oil pressure sensor. You would have to install it in the pan to get a better reading.
Best of luck, James