4.135 Ring Compressor

The ARP 4.135 Ring Compressor is a precision engine building tool designed for serious mechanics and engine builders working with high-displacement and performance engines. This specialized compressor addresses a critical challenge during piston installation: controlling ring spread while seating pistons into cylinder bores without damaging delicate ring grooves or cylinder walls. Whether you're assembling a stroker motor, rebuilding a race engine, or performing a complete long-block refresh, this tool ensures proper ring positioning and prevents costly installation errors.

The 4.135-inch size indicates this compressor is engineered for mid to large-displacement applications, making it suitable for various performance platforms requiring oversized pistons. ARP's precision engineering ensures consistent ring compression with minimal taper, allowing controlled, even band pressure around the entire circumference of the ring stack. The compact footprint—measuring 5.85 by 2.2 by 9.55 inches and weighing just 0.45 pounds—makes it portable and easy to position for work-bench or in-engine assembly.

Engine builders, performance shops, and DIY enthusiasts tackling serious engine work benefit most from this ARP tool. Its design minimizes ring binding and allows smooth downward travel, critical for preventing ring breakage during installation on engines with tight tolerances or aftermarket pistons. This tool is an essential addition for anyone looking to enhance their engine assembly process.