There were 2 types of early water pumps. One as shown in the picture has the piston that is actuated by a cam on the driveshaft. The other type, which in my opinion was problematic, had a “connecting rod” that was connected to the cam on the driveshaft. Exhaust gas which had oil residue was the lubricating mechanism. As wear took place, the “connecting rod’ would sag, and at some point, bind, with the result being catastrophic. I had an early 1922 with that type and when it let go, it blew a hole where the exhaust cutout was on the side of the mid section.
George
