Technology is provided for a fuel injector mounting system for mounting an injector to an engine cylinder liner. The system includes an injector adapter having an adapter body including a first end portion threaded for engagement with a cylinder liner and an injector port formed in the adapter body opposite the first end portion. The injector port includes a plurality of concentric bores configured to receive the proximal end portion of an injector. A flange extends transversely from the adapter body and a collar engages a portion of the injector and connects to the flange to retain the injector in the adapter. A transverse passageway extends through a sidewall of the adapter body and intersects the injector port and an annular fitting is disposed on the injector adapter for fluid communication with the transverse passageway. An injector support bracket attaches a distal end portion of the injector to the engine.