The shop manual for my old '84 F150 300 cid I6 engine states that the oil pump "Relief Valve Spring Pressure Lbs. @ Specified Length" should be "20.6 - 22.6 @ 2.49".
I am wondering if there is a way to translate that to what oil pressure should open the relief valve (though presumably the valve opens partly to fully over a range of pressure).
Given that the pressure spec is 40-60 psi at 2000 rpm, the relief pressure must be a lot higher than the "Spring Pressure." My '95 F150 with same engine and pressure spec, maxes out cold pressure around 55 psi, but I think I have a weak relief valve spring (for example my 1990 Ford 460 V8 maxes out cold around 75 and has similar hot spec: 40-65 psi).
Hey, the other weird thing is they give the pressure spec as a single number (275 kPa), followed by a range for psi (40-60). If I recall correctly 100 kPa is about 14.5 psi, so their kPa figure is about 40 psi. Strange.
I am wondering if there is a way to translate that to what oil pressure should open the relief valve (though presumably the valve opens partly to fully over a range of pressure).
Given that the pressure spec is 40-60 psi at 2000 rpm, the relief pressure must be a lot higher than the "Spring Pressure." My '95 F150 with same engine and pressure spec, maxes out cold pressure around 55 psi, but I think I have a weak relief valve spring (for example my 1990 Ford 460 V8 maxes out cold around 75 and has similar hot spec: 40-65 psi).
Hey, the other weird thing is they give the pressure spec as a single number (275 kPa), followed by a range for psi (40-60). If I recall correctly 100 kPa is about 14.5 psi, so their kPa figure is about 40 psi. Strange.