BMW E36 320i 325i M50 M50B25 M52 M3 S50 S52 IRON BLOCK UPGRADED SPORT BMW M50 M52 S50 S52 Oil Pump Upgrade Kit M52 oil pump mods with all OEM parts. S54 tensioner. M50 M54 YouTube BMW E36 320i 325i M50 M50B25 M52 M3 S50 S52 IRON BLOCK UPGRADED SPORT. The BMW M50 M52 S50 and S52 engines are notorious for their well documented problems stemming from harmonics. The vibration leads to the oil pump shaft becoming weak, causing it to either break or the oil pump nut to loosen and fall off, resulting in an immediate loss of oil pressure. Worry no more! 5150 has the solution! At the core of this kit is a hardened Chromoly shaft, meticulously centerless ground to guarantee absolute precision. This shaft is designed with an exclusive square key lock system, which not only prevents the gear from ever rotating on the shaft but also reinforces the mounting area, adding additional strength. Furthermore, we replaced the problematic oil pump nut with an extended length bolt, which is EDM drilled to accommodate safety wire for a secure fit in all conditions. Don't wait until your oil pump fails, leaving you facing expensive engine repairs! Key Features: Centerless ground shaft made from hardened Chromoly. Bolt with EDM drilling, including safety wire. Grade 8 extended length hardware for secure gear attachment. Left hand threaded to prevent unexpected loosening. Double D keyed shaft and drive gear. Fully serviceable and rebuildable without the need for grinding.