4.320 Ring Compressor

The 4.320 Ring Compressor from ARP is an essential tool for engine builders, mechanics, and serious automotive enthusiasts tackling piston and ring installation on high-performance and stock engines alike. This precision instrument compresses piston rings uniformly during block assembly, preventing damage to rings and cylinder walls that can compromise compression, blow-by, and long-term engine reliability. Whether you're rebuilding a small-block Chevy, preparing an LS platform for forced induction, or restoring a classic engine, a quality ring compressor is crucial for proper ring seating and wear patterns.

The ARP 4.320 Ring Compressor is designed to accommodate pistons with a bore size of up to 4.320 inches, making it suitable for a wide range of engine platforms. The compressor works by applying even radial pressure across all ring grooves simultaneously, collapsing rings safely into their grooves without binding or cracking them during piston insertion into the cylinder bore. Engineered steel construction ensures durability through repeated use, and the compact 5.75 x 2.2 x 9.7-inch form factor allows precise control and access in tight engine compartments.

Professional engine shops, custom builders, and DIY mechanics who demand precision depend on ARP ring compressors to eliminate installation errors and protect expensive pistons and rings. This tool is indispensable for achieving optimal engine performance and longevity, making it a must-have for anyone involved in engine rebuilding or performance modifications.