If your M50, M52, or M54 engine takes a few seconds to build oil pressure after sitting, there's a good chance that your factory oil filter housing drain back valve has failed. Over time, the factory plastic check valve degrades, allowing oil to drain completely out of the housing and back into the oil pan while sitting. Every cold start essentially becomes a dry start, resulting in a loud ticking noise and causing unnecessary wear on your engine's internals.

Unfortunately, BMW does not offer this check valve as a standalone part, forcing you to purchase a costly, complete oil filter housing assembly just to fix one failed plastic component. Thankfully, our team of BMW enthusiasts took note of this common failure mode and designed a permanent, cost-effective fix.

Our Billet Oil Filter Housing Drain-Back Valve is designed as a direct-fit upgrade for your factory oil filter housing. CNC-machined from high-strength billet aluminum, this upgraded valve restores positive sealing to keep the oil filter housing fully primed. Maintaining this hydraulic prime ensures rapid oil pressure stabilization upon startup, directly mitigating dry-start bearing wear and top-end lifter starvation without requiring the purchase of a complete OEM housing assembly.

Upgrade your engine build with Turner's WPC-treated Race Series Bearings, engineered for serious performance enthusiasts. Starting with ACL’s high-performance bearing shells, these Race Series bearings are built to withstand extreme RPMs and stress. Utilizing a "Duraglide" tri-metal construction and a high-strength overlay plate, these bearings offer superior oiling and heat resistance for high-RPM operation.

Our WPC-treated bearings take ACL’s already impressive design and enhance it even further. The WPC treatment process strengthens and smooths the bearing surface by firing high-speed, ultra-fine particles at the bearing shells, reducing friction and improving durability. This advanced surface treatment ensures smoother operation and improved heat dissipation, which are critical for any high-performance engine.

Key Features:

Duraglide Tri-Metal Construction: ACL's Race Series bearings feature a high-strength overlay for enhanced performance. Optimized Oiling: Designed to promote better oil flow during high-RPM conditions. Precise Fitment: Manufactured with OEM-level precision using micron tolerance machining. WPC-Treated for Strength: Surface treatment adds strength and reduces friction for improved engine performance. No Flash Plating: Allows for better heat transfer and bearing retention. Thermal Discharge Process: Smoother, stronger components through WPC’s unique thermal discharge technology. Enhanced Heat and Friction Resistance: Built to combat the biggest enemies of high-performance engines. Don’t settle for standard bearings—choose Turner Motorsport WPC-treated Race Series Bearings for the ultimate engine performance upgrade. Perfect for your next engine rebuild or rod bearing service!

The MINI N14 engine uses a traditional pencil coil design that operates using conservative dwell times and relatively low discharge energy. On stock vehicles, this system is sufficient. However, as cylinder pressures increase via higher boost, upgraded turbos, or ethanol-blended fuels, the strength required to bridge the spark gap increases substantially.

Under these conditions, standard N14 coils reach their electrical limits, resulting in high-RPM spark blowout, misfires, or reduced flame front propagation. To solve this issue, our team engineered the B-Series Coil Conversion Kit, which adapts modern BMW B48/B58 ignition technology to the N14 using proprietary brackets, standoffs, and wiring harness adapters. Our performance B48 ignition coils feature a significantly lower primary resistance and an optimized secondary winding structure, allowing them to store and release up to 2.3x more spark energy than the factory N14 ignition coil.

This clean, coil-on-plug upgrade drops directly into your valve cover without bulky external boxes or messy wiring. Whether you need an ignition service or are building a tuned N14, upgrade to B-Series ignition coils and experience improved spark energy and long-lasting performance.

Heat is the enemy of lap times and engine longevity. BMW calibrated the factory oil thermostat on the N54, N55, and S55 platforms for rapid warm-up and emissions targets, running oil temperatures uncomfortably hot under prolonged load. When you’re pushing full throttle down the straight or stacking laps in midsummer, you need thermal headroom long before factory thresholds are reached.

The Turner Motorsport Oil Cooler Thermostat Housing drops your thermostat threshold to 70°C, circulating oil through the cooler early to build a buffer against heat saturation. Engineered for hard-driven road course and track day cars, the housing is protected with a Type III black hardcoat anodized finish for maximum resilience against thermal cycling and harsh track environments. Build flexibility is built right in: retain your OEM hard lines for a simple, direct-fit cooling upgrade, or adapt to full braided lines using our Turner AN Adapter for dedicated competition oiling systems.

If you own an M57-equipped BMW, you already know this twin-turbo diesel powerplant is an absolute torque monster. What you might also know is that all that low-end grunt and high-compression diesel vibration wreaks absolute havoc on your accessory drive system.

From the factory, both the E90 335d and E70 X5 35d utilize a rigid alternator pulley. With each cylinder's fire, the crankshaft experiences a violent micro-acceleration. Because the alternator has a heavy internal rotor spinning at high speeds, it wants to keep spinning at a constant rate. When the engine suddenly slows down (even minutely between firing cycles), the alternator fights the belt. This constant tug-of-war results in extreme stress on your engine's belt-driven components. At best, it’s an annoying, unrefined chirp at idle; at worst, it’s a ticking time bomb for your expensive harmonic balancer.

To solve this issue, many enthusiasts choose to run a clutched alternator pulley (also called an overrunning alternator pulley). A clutched pulley allows the alternator to "freewheel" or coast when the engine slows down, completely isolating its rotational inertia from the belt drive to prevent component wear. While the N52's clutched pulley (12317560483) is a straight bolt-on, the offset is incorrect for the E70 X5 35d's accessory drive. Thankfully, our engineers designed this zinc-coated spacer to provide the precise amount of spacing needed to perfectly align the new pulley with existing belt drive components.

If you own an M57-equipped BMW, you already know this twin-turbo diesel powerplant is an absolute torque monster. What you might also know is that all that low-end grunt and high-compression diesel vibration wreaks absolute havoc on your accessory drive system.

From the factory, both the E90 335d and E70 X5 35d utilize a rigid alternator pulley. With each cylinder's fire, the crankshaft experiences a violent micro-acceleration. Because the alternator has a heavy internal rotor spinning at high speeds, it wants to keep spinning at a constant rate. When the engine suddenly slows down (even minutely between firing cycles), the alternator fights the belt. This constant tug-of-war results in extreme stress on your engine's belt-driven components. At best, it’s an annoying, unrefined chirp at idle; at worst, it’s a ticking time bomb for your expensive harmonic balancer.

To solve this issue, many enthusiasts choose to run a clutched alternator pulley (also called an overrunning alternator pulley). A clutched pulley allows the alternator to "freewheel" or coast when the engine slows down, completely isolating its rotational inertia from the belt drive to prevent component wear. While the N52's clutched pulley (12317560483) is a straight bolt-on, the offset is incorrect for the E90 335d's accessory drive. Thankfully, our engineers designed this zinc-coated spacer to provide the precise amount of spacing needed to perfectly align the new pulley with existing belt drive components.