The 2 big issues over the RB30 relate towards the oiling process and crank collar. This isn’t precise to just the RB30 sequence, as being the RB20/twenty five/26 also have observed problems Together with the oil pump and oiling devices. They all put up with this problem (early RB26 only). https://caidennxabf.blognody.com/27830957/how-nissan-skyline-rb26-engine-can-save-you-time-stress-and-money