Yes, the sludge trap has been cleaned. I am familiar with the fact that S/S oil has detergent properties so, without a filter, will need to be changed often. I was a little more concerned about having S/S oil as I have heard, perhaps wrongly, that it can cause roller & ball "skid" in bearings, namely the drive side. No problem with the timing side as this is, as you know, a plain bearing. Might stick to straight old fashioned 20/50 & change often.
Thanks for your help.
Stu