Quote Originally Posted by Joseph206 View Post
So, the pop it valve is just a primitive thermostat that works on , as the temp rises the pressure rises and pops the valve?????

Add: Sorry it cant be, as the temp rises the pressure goes down. I am confused on how the popit valve works.
Close. The pop-it valve the predates the vernatherm. They do the same thing but by different methods.

The pop-it valve controls the oil flow through the oil cooler based off of the pressure of the oil. Cold oil is thicker and therefore the pressure is higher, pushing the valve off of the seat and allowing oil to bypass the cooler. Bypassing the cooler, the oil just circulates through the engine (sucked out of the oil sump, through the oil pump, filter, oil galleys, out the the heads etc and back to the oil sump). When the oil gets warmer it get thinner and the pressure goes down. Lower pressure lets the pop-it valve close and the oil then goes through the cooler as well as everything else.

The vernatherm goes in a slightly different part of the oil system (though very close to the same place) and controls the oil flow going through the cooler by temperature. It works almost identically to the thermostat in your car. It also has a spring but what causes it to open and close is a bi-metallic part that changes with temperature. It can more easily regulate the flow to the cooler because it tends to open slower and will meter flow (verses the pop-it valve is more either open or closed)