Oil Pressure Control

[Mike Guenther]

Ben - soapy water and a soft brush.

Boswoj -"Same reason that fuel pressure regulators work - if all other factors are equal, higher pressure means higher velocity and higher GPM."

The purpose of a regulator is to maintain a desired pressure. It can only do this within the rated flow capability of the specific regulator. Controlling downstream pressure they’re called regulators, controlling upstream pressure they’re called back pressure regulators or relief regulators. The regulators’ only purpose is to maintain the set point pressure. As the flow increases the set point delivered usually drops off (droop). Once the flow reaches the capacity of the regulator the pressure will drop off significantly depending on the downstream demand. Piloted regulators, ( a regulator that controls a regulator), will have better (less) droop characteristics but will be slightly slower than a direct operated regulator at responding to changes in downstream pressure caused by changes in demand for flow. The purpose of controlling the pressure delivered is to get a controlled flow through a given system without fluctuations due to changes upstream. On a fuel system the pump delivers an output that would change pressure significantly with changes in demand for fuel. The regulator supplies a constant pressure so that the rate of flow into say the float bowls of a carburetor is fairly constant and sufficient for demand yet not too much pressure that the float valve can’t shut it off. Want to know more about regulators? Go to www.fisherregulators.com Enjoy!

[JeffG]

There is certainly an oil velocity that is too high for efficient cooling. It would probably have something to do with the flow regime and developing a tunnel inside a slowly moving outer layer of fluid, which acts as insulation. Most high quality oil coolers have turbulators on the inside surface to promote mixing and maximize heat transfer.

Cavitation must be avoided in the case of a coolant pump, hence slower speeds and the use of restrictors to elevate the fluid pressure in the pump. Funny how adding a restriction can increase the flow rate!!

[Karl Bocchieri]

Get your oil cooler ultrasonicaly cleaned. The oil cooler on a 2nd gen RX-7 is a great unit but after 60,000 miles on a street car they tend to get gunked up. Simple hot tanking it does not get out all the stuff. The shop I brought mine to runs hot chemicals through it while it's in a ultrasonic tank. The vibrations break up all the crud and then it's flushed out. Best $50 bucks I spent, with my dual pass radiator, my temps never go above 190.