Here is the best explanation regarding the oiling issue:
https://mrbizzle.wordpress.com/2010/02/24/84/
Do some internet searching to determine the best route for your situation, not everything on that page is required, just recommended to address the entire situation.
Some more info here as well as in the link to the Skylines Forum:
http://www.driftworks.com/forum/tech...wers-here.html
^#1,2, and 3 in the list there is what I'd recommend unless you are circuit racing or drifting.
Unless you are having machine work done on the head, in which case you might as well have #4 and #5 done in the process.