Engine Case 9/16" Welch Plug

Steel 9/16" welch plug for early engine cases are used to form the internal cavities in the engine case, forming a coolant passage.
Welch plug is used to seal passages created for internal oiling, on oil pump body and engine case. The welch plug expands for a permanent seal when hit with dull punch, plugs are not reusable. Check the outer diameter of the plug before installation. The welch plug are what the Harley-Davidson factory used for many years. Welch plugs manufactured since 1909 in the U.S.A.