Re: 5.7 Merc Oil Pressure
Well how else would you be seeing 75 psi on your gauge with a 70 psi pump?
That's easily explained with an electric gauge and the limited accuracy of the sending unit, and the gauge itself. The only way to know the exact pressure, would be with a mechanical gauge.
Just got off the phone with customer support, and they had some very good information. The rated 70 PSI output, is at 70 degrees F, using 10W oil. He explained that the 70 PSI output will vary slightly, depending on temperature, and the viscosity of oil used. He went on to explain that the spring in the pump does indeed limit the output pressure, by effectively increasing the clearance between the gears and the wall of the pump surrounding the gears. This causes the pump to be less efficient, resulting in a drop of the output pressure. He went on to say that as long as everything else in the engine oiling system is operating as it should, there should not be any issues with the higher volume pump. He explained that these pumps are beyond what my engines require, however they will continue to work just fine.
I will report back again, once I have the WOT run on the weekend.
