its hard to see the pump screen in the picture but one should be able to inspect the oil pan for signs of scuffing around the pump pick up area to determine if any loose parts have been there.(if screw and washer has been there,they rotate around and draw a circle on the pan) once the washer spins off the screw it goes to the center of the screen and spins till it wears the screen,then the gear drive pump locks. in hind sight a simple convex screen instead of concaved desigh would help save these engines.
if anyone ever needs i do have sleeves that fit these engines that allows you to sleeve it for the the 3liter piston.
larry perkins