My does just as you describe.
By the way, increasing the initial air pressure will not increase the pressure; you will have a larger volume of air and less
oil in the accu. at equilibruim.
The reason it drops to around 20 psi is that you are displacing the
oil out of the accu. into the engine; the air is expanding and dropping pressure as the
oil goes into the galleries until the pressures are equal(20 psi of oil on one side 20 psi of air remaining on the other side- with the piston bottomed out after full stroke). If for example, the 70 psi oil charge moves the piston to about 2in from the end of the cylinder resulting with 70 psi air on the air side of the piston. They will equalize to about 20 psi, when the piston goes full stoke, then slowly drop to zero as the oil leaks thru the bearings.
Bottom line; everything is hunkeedory
gn
