Product Description
BMW S85 Race Series Engine Build - ZNM Performance
ZNM Performance Race Series Engine Build Program
Introducing our BMW S85 engine program—built for enthusiasts who demand motorsport-grade precision, improved durability, and reliable power from the legendary high-revving 5.0L V10. This page applies to all S85-equipped models, including the E60 M5 and E63/E64 M6.
The BMW S85 is a naturally aspirated 5.0L V10 with individual throttle bodies, a high 12:1 compression ratio, and Formula 1-inspired architecture. However, factory rod bearing clearance issues, aging VANOS systems, and extreme heat cycling make these engines prime candidates for a full race-spec rebuild.
That’s where our S85 engine build program comes in. Every engine is fully disassembled, cleaned, and inspected. We install forged internals, apply precision headwork, and offer custom upgrades like stroker cranks or dry sump conversions for competition builds. Whether you're chasing a high-revving street setup or building a naturally aspirated track weapon, our Race Series S85s deliver confidence at 8,500+ RPM.
Our facility in Pompton Lakes, NJ builds engines for customers across the U.S. and internationally. All engines are fully disassembled, measured, and assembled in-house with final clearances precisely set by our team. Please inquire about international shipping options.
Key Features and Options for Our Built S85 Engines
- Forged pistons and custom lightweight connecting rods rated for high-rev abuse
- Optional billet stroker crankshafts for increased displacement and torque
- Blueprinted rotating assembly balanced to motorsport tolerances
- Rod bearing clearances adjusted to mitigate known factory weaknesses
- Built to withstand 9000 RPM+ with proper tuning and oiling upgrades
Cylinder Head Upgrades for Your S85
- Multi-angle valve job with flow-optimized porting available
- Upgraded valve springs and titanium retainers for sustained high RPM
- VANOS unit rebuilds and cam timing adjustments available
Bearing Upgrades for Your S85
- ACL and King race-grade bearings specifically chosen for S85 oiling needs
- Crank journals polished and measured with micrometer and bore gauge
- Oil clearances set to match viscosity, load, and rev targets
- Ideal for both street-driven M5/M6's and dedicated circuit builds
Frequently Asked Questions (FAQ)
Q: Is the stock S85 engine reliable above 8000 RPM long-term?
A: From the factory, S85s are prone to rod bearing wear, VANOS failures, and oil pressure issues at high RPM. Our builds address all known weak points using upgraded parts and precision machining to safely run 8500+ RPM.
Q: Can I build an S85 for forced induction?
A: Yes. We offer low-compression forged piston options and stronger rods/crankshaft options for customers running superchargers or turbo systems on the S85, with tuning support available.
Q: Do you offer dry sump systems?
A: Yes, for competition builds. We can integrate a multi-stage dry sump oiling setup to eliminate oil starvation and allow safe operation under high G-loads and sustained high RPM.
Q: What head studs do you use?
A: We offer ARP 2000 and ARP 625+ head stud kits for the S85, depending on compression ratio and target RPM.
Q: How do you set bearing clearances?
A: We manually measure each crank journal and housing bore using precision tools and set clearances based on oil viscosity, redline, and bearing material—not guesswork.
