The two major difficulties over the RB30 relate for the oiling procedure and crank collar. This isn’t distinct to simply the RB30 series, since the RB20/twenty five/26 even have mentioned challenges With all the oil pump and oiling devices. All of them are afflicted by this difficulty (early RB26 only). https://nissan-skyline-rb26-engin60369.blog-ezine.com/28321885/considerations-to-know-about-rb26dett-complete-engine