Sundstrand Series 90 Adjustable Charge Relief Valve Change
It gives new design to the shim so that it will give different pressure adjustments that the charge pump can go. The settings on the charge pump are 290,348 and 406 PSI. It will improve the charge relief valve poppet and plug. The charge relief may go out from the pump about .27 inches. It will go out more than the shim adjustment.
You will need to put in a gauge so it will size up the charge pressure. Let out the adjustment lock nut with a hex wrench and activate the pump at n input speed of 1700 to 2000 rpm. Then turn the adjustment plug with screwdriver and not the charge pressure. If you use clockwise settings it will increase the setting and counterclockwise will decrease the setting by 50 PSI per turn. When you get it like you want it, torque the lock nut to 34-41lb per foot and take off the charge pressure gauge.
And for a service part, the adjustable charge relief valve kit will be available. You can use it on older units.
Call for more details