The M50 (and M50TU/M52) oil pumps are a sore spot for many - especially for those who have raised their rev limits or spend a lot of time at high RPMs. The single nut holding the sprocket to the rotor shaft vibrates loose over time causing loss of oil pressure and catastrophic damage to the engine in a matter of seconds. There are many things that cause this to occur: A worn chain, worn sprockets and crank harmonics (mainly on the longer stroke engines such as 2.8 and 3.0 models). A common “fix” is to weld the nut to the shaft and ‘send it’, however, due to the chain slap from an ever-wearing chain/main crank sprocket, in less than 20,000 miles this can end up snapping the shaft instead of loosening the nut.

The overlooked design from BMW can be fixed long-term without welding the inside of your engine and without great expense (especially compared to the price of a new engine or rebuild) with a chain tensioner and a 7-bolt oil pump. The tensioning unit we currently use is in OEM application in other vehicles and is proven over many years to reduce the standard M54 chain slap on even old, worn chains. The oil pumps we modify use a custom machined hardened shaft with completely overhauled internals and a custom built sprocket. The sprocket is then held to the shaft with up to 7 hardened bolts and genuine NordLock anti-vibration washers (we will supply with 4 bolts and 3 nordlock washers - see product photos).

From us, you can buy:

• A chain tensioner and a new chain (with a guide on how to fit the tensioner)

• A completely reconditioned, modified oil pump and custom sprocket

• The full works - oil pump as above, sprocket, chain, and tensioner with guide

Everything you choose to buy comes with after-sales support. If you get stuck or can’t fit the parts yourself, you can ask us for help - we’re more than happy to support you through the process.

Please note: This product (oil pump, or oil pump and chain tensioner kit) has a surcharge built in to the price. Once you have received the new unit, you can return your old one for a refund of £80