The two huge problems to the RB30 relate for the oiling technique and crank collar. This isn’t specific to just the RB30 series, as being the RB20/25/26 also have mentioned concerns with the oil pump and oiling techniques. All of them are afflicted by this concern (early RB26 only). HKS https://nissanskylinerb26engine15825.webdesign96.com/28731347/what-does-motor-rb26-mean