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ss3011 · 03-08-2016, 07:44 PM

ATF is about the same viscosity as 20 weight oil . Lacquer thinner is very low viscosity, and without any lubricity , I am surprised the pump did not seize during the test . We used to use a test fluid at HydraMatic when we would test pumps, it simulated 200 deg Dextron 3 fluid . We got rid of it and used Heated Dex3 because it was more accurate to test pump efficiency with the pump and fluid running at operating temperatures. Clearances don't change much if the pump body and the gears are a similar material, but make a big difference if the pump body is aluminum, and the gears are steel . Also it is more efficient to have the regulator designed to bypass back to the suction side of the pump gears , a blowoff regulator would tend to aerate the oil in the pan . Aerated oil does not provide a good lubrication film for bearings . One of the purposes of a dry sump tank is to separate the air from the oil, so the pump is pumping clean oil. What would be great if someone would develop a Variable Displacement pump for these engines, then you would only pump what you actually need .

03-08-2016, 07:44 PM	#2
ss3011 Senior Member Join Date: Feb 2002 Location: Southeast Michigan Posts: 909 Likes: 70 Liked 239 Times in 114 Posts	Re: oil pump help ATF is about the same viscosity as 20 weight oil . Lacquer thinner is very low viscosity, and without any lubricity , I am surprised the pump did not seize during the test . We used to use a test fluid at HydraMatic when we would test pumps, it simulated 200 deg Dextron 3 fluid . We got rid of it and used Heated Dex3 because it was more accurate to test pump efficiency with the pump and fluid running at operating temperatures. Clearances don't change much if the pump body and the gears are a similar material, but make a big difference if the pump body is aluminum, and the gears are steel . Also it is more efficient to have the regulator designed to bypass back to the suction side of the pump gears , a blowoff regulator would tend to aerate the oil in the pan . Aerated oil does not provide a good lubrication film for bearings . One of the purposes of a dry sump tank is to separate the air from the oil, so the pump is pumping clean oil. What would be great if someone would develop a Variable Displacement pump for these engines, then you would only pump what you actually need .