Pure Performance McLaren 4.0L M838 Stroker Kit

The Pure Performance high-performance stroker kit for McLaren M838 engines offers an opportunity to enhance your vehicle’s performance. By increasing the displacement of your McLaren 570, 650, or 675 from 3.8L to 4.0L, akin to the engines found in the 720, 765, and 750 models, this kit provides a significant boost.

Included in the package are all the necessary components to convert your 3.8L McLaren engine to 4.0L, ensuring increased horsepower, improved throttle response, and specifically engineered parts to handle the additional stress on your engine.

This kit features a billet crankshaft with the standard 720 McLaren stroke, custom-designed sleeves by Pure Performance, bespoke pistons, and Billet 4340 connecting rods and pins. Additionally, it comes with essential components like friction washers, piston rings, main bearings, thrust bearings, rod bearings, main bolts, head studs, and all required gaskets.

Early on, it was observed that many McLaren engines experienced rod failures, particularly in cars with performance enhancements such as tunes and exhaust modifications. The increased torque generated often pushed the piston and rod combination beyond their intended limits. McLaren’s unique piston design, featuring a short strutted skirt and piston-guided rod, reduces friction but poses challenges for high-power engines. This design can cause the piston and rod to deviate from their optimal alignment, leading to bent rods and potentially catastrophic engine failures.

To address this issue, Pure Performance developed a proprietary connecting rod and piston design to improve the engine’s ability to handle high horsepower and torque. The new design replaces McLaren’s piston-guided small skirt rod with a sturdier alternative that helps maintain piston alignment within the bore. Furthermore, Pure Performance engineered connecting rods that guide and maintain the rods at a 90-degree angle to the crankshaft, preventing unexpected bending in high-torque situations.

These modifications are standard in all Pure Performance high-horsepower McLaren builds. The rod-guided pistons ensure proper alignment, mitigating the risk of bent rods and engine failures. While Pure Performance estimates that their internals can handle over 2000hp, current clutch technology limits power delivery to around 1350hp in McLaren vehicles. Consequently, all stage 2 McLaren engine builds from Pure Performance feature rod-guided pistons.

Does Not Include Labor – Reach out for a quote.

For inquiries and purchases, please contact us directly at sales@bmwengine.com