Large Valve Spring Compressor Designed to compress valve springs on overhead valve engines. Includes two valve spring adapters, which fit valve spring retainers up to 1 (25 mm) and 1-3/16 (30 mm). Unique, direct action compressor lever gives better visibility of valve spring retainers located in difficult access areas. Jaw opening of 1-3/8 to 5-5/8 (35 mm to 142 mm); throat clearance of 5-7/8 (150 mm). No. 4572 Large valve spring compressor.