The correct ball check lift for your water ball checks according to the Stanley Dealer Bulletin " number 42 dated May 13, 1918 is 0.057" I have adjustable ball checks on my water pump ball check caps and they are made with 24 tpi stainless adjusters. An early SACA "The Steam Automobile" had the article on how to make them. I have found that one full turn from closed, or 0.041" lift works best for my water pumps. They make very little noise and they work at all speeds. If your check ball seats get beat in, then a milling cutter has to be plunged into the bore to reduce the seat width to an efficient size. Otherwise, the water cannot escape the beat in seat fast enough to work well. With too much lift, the check balls will hammer them selves in and also will not operate properly at higher speeds.
I set my condensing car's "slower speed pump" ball checks at 0.050" and my non- condensing cars' "higher speed pump" ball checks at 0.041".
The width of the seat shouldn't be any more that 1/32" wide. A sharp edge? I have never done that, but the bump of a small hammer and a brass driver quickly seats the check ball. I do not use copper washers under the caps. If you have an issue with leakage, wrap a couple of turns of teflon tape around the cap before screwing it down. That also helps preserve the threads too. The Stanley dealer Bulletins are available from the Stanley Museum. There is a pretty heftly pile of Bulletins to go through. Through the last 25 years I have added to them with information that I have picked up along the way. Using it's index, I have added the new information where it belongs and noted the new information in the index.
The optimum diameter for the bore that the ball seats on, is 0.707 x OD of ball. (COS 45) This will ensure that the contact angle is 45°.
Lift should be restricted to no more then 1/6 th ball diameter
The minimum diameter of the bore that the ball moves in, is 1.31 x OD of ball. This will just give enough clearance for the liquid to flow past the ball. It is recommended that 2 x OD of ball is used to provide reasonable flow conditions around the ball.