Mnethercutt
Member
Reading the service manual, and I'm a bit confused as to how this mechanism is adjusted. The manual says you can adjust oil pressure by adding or removing shims behind the spring, but it doesn't say which option adds or lowers oil pressure. I am assuming (and we know what that makes out of u and me) that adding more shims will increase pressure, but the description of how the regulating piston works makes it sound otherwise. I'll include snippets of the sections below, but if someone could confirm that'd be great.
On the operation of the pressure regulating mechanism:
"A pressure-regulating mechanism is built into the oil pump upper body. This mechanism consists primarily of a plug which is held against a seat in the body by a spring, set to a predetermined pressure. Pressure may be adjusted by changing the number of spacers behind the spring. When oil pressure is greater than spring pressure, the valve is raised from its seat, permitting enough oil to bypass to maintain desired pressure."
On adding and removing shims:
"Note: Oil pressure is adjusted by adding or removing shims behind pressure regulating spring. Refer to specifications at the end of this group for required pressure."
(The specifications only list that pressure should be between 35 and 50 PSI. That first text almost makes it sound like removing shims will raise oil pressure to me?)
On the operation of the pressure regulating mechanism:
"A pressure-regulating mechanism is built into the oil pump upper body. This mechanism consists primarily of a plug which is held against a seat in the body by a spring, set to a predetermined pressure. Pressure may be adjusted by changing the number of spacers behind the spring. When oil pressure is greater than spring pressure, the valve is raised from its seat, permitting enough oil to bypass to maintain desired pressure."
On adding and removing shims:
"Note: Oil pressure is adjusted by adding or removing shims behind pressure regulating spring. Refer to specifications at the end of this group for required pressure."
(The specifications only list that pressure should be between 35 and 50 PSI. That first text almost makes it sound like removing shims will raise oil pressure to me?)
