Originally Posted by David Pozzi (Post 631702)

The return line should allow the fluid to upwell slightly/gently inside, and allow any bubbles to burst. I had trouble with a cheap tank that had an abrupt 90 deg "cap" welded inside of the return fitting, I guess to turn the flow and spin it around. This foamed the fluid like crazy! I welded in a new return fitting angled upwards 10 degrees and it was shaped with a tapered ID small to large to slow the flow gently. It was the opposite of a nozzle shape. If the return line flow can travel down and right out of the outlet to the pump, it won't help the fluid to defoam. Even a simple baffle can help, that's all the stock pumps have. The tank return fitting to the pump must not restrict the flow or force the flow to turn abruptly or it will foam the fluid.

The outlet fitting to the pump should have a radiused edge inside the tank. There is a lot of suction in the line at higher rpm's and it can cause cavitation foaming if the oil flows over sharp edges. -10 fittings and hose should work, but all edges should be smoothed. My tank had a screw in outlet fitting, male on each end, it had an ID that looked too small so I drilled it out. The idea was to allow the oil speed to increase gradually as it goes from tank to hose.