99.75mm Ring Compressor

The ARP 99.75mm Ring Compressor is a precision engine assembly tool designed for professional mechanics and engine builders working with pistons in the 99.75 mm bore range. This tapered aluminum compressor is engineered to safely compress piston rings during piston installation, preventing ring damage and ensuring proper positioning within cylinder bores. Whether you're rebuilding a high-performance engine, servicing OEM equipment, or performing routine engine maintenance, this ring compressor delivers the controlled compression necessary for reliable assembly.

Constructed from black anodized aluminum, the 99.75mm Ring Compressor features a tapered design that gradually compresses rings as the piston is inserted into the cylinder bore, distributing pressure evenly and reducing the risk of ring breakage or binding. The tapered geometry allows rings to expand naturally as they exit the compressor and enter the cylinder, ensuring proper seating and ring groove alignment. Weighing just 0.66 lbs with compact dimensions of 5.75 x 2.25 x 9.65 inches, this tool is lightweight yet robust enough for repeated professional use. The anodized finish provides corrosion resistance and durability in shop environments.

This ring compressor is ideal for engine builders, diesel technicians, and automotive professionals rebuilding engines with 99.75 mm bore specifications—a common size in many performance and industrial applications. Installation is straightforward: slide the compressor over the piston with rings installed in their grooves, tighten the band to compress the rings, and guide the piston assembly into the bore. The tool's precision bore sizing ensures compatibility and prevents over-compression, which can crack rings or damage bore walls. ARP's reputation for manufacturing excellence guarantees this compressor will perform reliably across countless engine assemblies.