An accumulator clamp for an accumulator assembly in an engine assembly is disclosed. The accumulator assembly further includes an accumulator body and a fuel line adapter connected thereto, and the accumulator assembly is mountable into a cylinder head accumulator bore of a cylinder head. The accumulator clamp includes a clamp body having a clamp accumulator bore receiving an end of the accumulator body, and a bolt bore on either side of the clamp accumulator bore for receiving threaded portions of accumulator mounting bolts that secure the accumulator assembly to the cylinder head. The bolt bores include bolt slots through the walls of the accumulator body so that the threaded portions of the accumulator mounting bolts are insertable into and removable from the bolt bores through the bolt slots to allow installation and removal of the accumulator assembly without disassembling components of the engine assembly around the cylinder head.