1) MAIN CAP BOLTS

It is best practice to replace main cap bolts rather than reuse them. Main Bolt Set [Genuine BMW] bolts are suitable for moderate performance engines. For high-performance or boosted engines, upgrading to Main Stud Kit [ARP] is recommended to prevent main cap walk and protect block threads. Installation may require line honing.

2) CONNECTING ROD BOLTS

It is essential to replace the original connecting rod bolts. Con Rod Bolt Set [Genuine BMW] is ideal for use with standard connecting rods; genuine connecting rod bolts are single-use torque-to-yield bolts. 2000 Series Con Rod Bolt Set [ARP] are also suitable for standard connecting rods and offer increased strength and reliability; ARP rod bolts may be reused upon inspection. 2000 Series Con Rod Bolt Set [ARP] (FREE with purchased forged MPR con rods) is required when using forged MPR connecting rods and ensures maximum durability for high-performance or race builds.

3) CYLINDER HEAD BOLTS

It is essential to replace original cylinder head bolts. Cylinder Head Bolts [Elring] (M10x110mm) are OEM, single-use torque-to-yield bolts suitable for standard and moderate performance engines and are suitable for standard OEM-style head gaskets. They are not recommended for performance cut-ring head gaskets. Cylinder Head Stud Kit [ARP] (M10) is a direct-fit upgrade offering increased clamping force and are reusability upon inspection. This kit is most popular for performance and boosted engines. Cylinder Head Stud Kit [ARP] (M11) provides the highest clamping force and is intended for high-boost applications; installation requires drilling and tapping the block for larger threads and can also be used as an upgrade when repairing damaged M10 threads.

4) MAIN BEARINGS

Standard Bearings [KOLBENSCHMIDT] (STD size) are OEM-quality and suitable for standard rebuilds. RACE SERIES BEARINGS [ACL] provide maximum reliability in high-performance, high-RPM engines with improved load capacity and durability. Standard crankshafts can use STD or STD-HX options, while +0.025mm and +0.25mm bearings are for custom clearances or machined crankshafts.

5) BIG END BEARINGS

Standard Bearings [KOLBENSCHMIDT] (STD size) are OEM-quality and suitable for standard rebuilds. RACE SERIES BEARINGS [ACL] provide maximum reliability in high-performance, high-RPM engines with improved load capacity and durability. Standard crankshafts can use STD or STD-HX options, while +0.025mm and +0.25mm bearings are for custom clearances or machined crankshafts.

6) EXHAUST MANIFOLD STUDS

Original exhaust studs can be reused, though replacement is best practice. Standard Exhaust Stud Set [Genuine BMW] is OEM-quality and suitable for standard exhaust manifolds. Modern Exhaust Stud Set [Genuine BMW] features longer threads and a hex protrusion, allowing use with thicker exhaust or turbo manifolds and easy installation with a torx socket. High Performance Inconel Stud Kit is KAZZ Engineering’s strongest option; 45mm Inconel studs with CNC-machined M7x1.0 to M8x1.25 ends and a hex broached tip allow easy installation with a 4mm Allen wrench, offering maximum strength for high-performance applications.

7) EXHAUST MANIFOLD NUTS

Original exhaust nuts can be reused, though replacement is best practice. Standard exhaust nuts [Genuine BMW] are OEM-quality and suitable with standard genuine M7x1.0 exhaust manifold studs. The High Performance Nuts (M8) are included (and only suitable) with the purchase of the High Performance Inconel Exhaust Stud Kit.