The ZRP Stroker crankshaft for the BMW S14B20 engine increases stroke to achieve a higher cubic capacity. Its 80 mm stroke increases the distance traveled by the pistons and the volume displaced within the cylinders. The final cubic capacity depends on the selected bore.
Part number C-BMW-001 is fully CNC-machined from solid 4340 aerospace-grade steel. Its design features Aero-Wing-profiled counterweights, direct oil supply to the crankpins, and surface treatments designed to improve abrasion resistance.
Technical Specifications
- Brand: ZRP
- Manufacturer Part Number: C-BMW-001
- Engine Application: BMW S14B20
- Configuration: Stroker, increased stroke and cubic capacity
- Manufacturing: CNC machined from solid stock
- Material: 4340 billet steel, aerospace grade
- Stroke: 80.00 mm
- Journal diameter: 54.99 mm
- Rod journal diameter: 47.991 mm
- Weight: 20.30 kg
- Balancing: Performed on Sunnen equipment, with inspection report provided
Design and oiling
- Aero-Wing counterweight: profile designed to reduce drops caused by air and oil turbulence in the crankcase.
- Direct oil ducts: oil supply designed to improve crankshaft oiling.
- Chamfered oil holes: finish on the oiling line inlets.
- Bearing contact radius: geometry designed to better distribute mechanical stresses.
- Lightweight crankshaft journals with a conical profile: a design that contributes to weight reduction.
Manufacturing Processes and Inspections
- Full CNC machining: precise production of geometries and bearing surfaces.
- Plasma ion nitriding: surface hardening of the treated areas.
- Multi-stage heat treatments: to achieve the desired mechanical properties.
- Shot blasting: mechanical surface treatment.
- Magnetic particle inspection on each part: detection of surface or near-surface defects.
- Heat treatment to improve abrasion resistance.
- Micro-polishing of bearing surfaces: a finish designed to extend the service life of the bearings.
- Ultrasonic and X-ray inspections: verification of material integrity.
Mounting in Stroker S14B20 configuration
The transition to an 80 mm stroke requires specifying a compatible set of connecting rods and pistons. Be sure to check the position of the pistons at top dead center, the compression ratio, the bearing clearances, and the clearances in the cylinder block before assembly.
The choice of bore determines the cubic capacity achieved with
