Power steering bother

[David Pozzi]

How big is the hose from tank to pump inlet? It needs to be -10 minimum, AND have no restrictions or sharp edges or you can get cavitation & foaming.
In the photo, it looks small.

[Spiffav8]

Originally Posted by David Pozzi

How big is the hose from tank to pump inlet? It needs to be -10 minimum, AND have no restrictions or sharp edges or you can get cavitation & foaming.
In the photo, it looks small.

You're just a problems solver aren't ya.

[RocketsGarage]

Originally Posted by David Pozzi

How big is the hose from tank to pump inlet? It needs to be -10 minimum, AND have no restrictions or sharp edges or you can get cavitation & foaming.
In the photo, it looks small.

It's hard to see from the picture but it's a -10 from the reservoir to the pump.

[David Pozzi]

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.

[Vince@Meanstreets]

also make sure your pressure and return lines are not swapped.

[RocketsGarage]

Anyone recommend a direct replacement high performance pump for this setup? Vintage Air Front Runner.

[dontlifttoshift]

I don't think it is a pump problem. Is the fluid level above the return port in the reservoir?

If you want to change the pump, I would buy this one from Jones.



http://www.jonesracingproducts.com/ps.html#psalr

The reservoir is larger and stronger than a stock plastic one and has two pipe thread ports for the return, one on the side and one on the bottom, to make plumbing easier. It fits fine on a front runner.

[frojoe]

Originally Posted by David Pozzi

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.

Excellent points here David.. for the oulet, a radius'd inner edge and taper with big end on the reservoir side will definitely help to be friendlier to the fluid near the wall of the reservoir around the fitting, allowing the fluid to have a less harsh 90* turn that is gets violently sucked around.

[RocketsGarage]

I think we got it. Swapped out the rack (only thing that hadn't been changed), Changed the flow valve from 3 GPM (DSE recommended) to 2 GPM (Morrison recommended). That required re-plumbing the pressure line. Seems to have done the trick.

[David Pozzi]

Thanks for letting us know.