CUMMINS-6CT-LOCK-VALVE-1-groove

3901177 is a single-groove valve lock for Cummins 6CT engines, the small collet that seats into one groove machined on the valve stem to retain the spring under compression. The groove count matters for fitment — a lock built for a different groove configuration won't seat correctly even if it looks similar — so matching this exact reference to your valve stem pattern is important rather than optional. Orange.net.za ships this part fast, South Africa-wide.