Schuman oil pumps

[Ratsun]

Anyone here had much to do with schuman oil pumps?
I spent big $ and having some issues
The pump I bought is for a Sbf
Below is the product description


Small Block Ford 289 302 5.0 high performance oil pump Pro Maxx Series standard volume gear pressure balanced; 140% Check ball; External bypass Pro Maxx series pumps are intended for use in race applications only. They are not for street use. Schumann part number EW140SV

Problem is I had it put on a special test bench and with the relief set at 80 psi it will start bleeding off at around 50 psi and the faster you turn it it will just keep making pressure way past 100psi
Also the oil bleeds off through the external bypass hole and also comes out the rear of the pump where the spring sits,
Any one used them?

[Dave Koehler]

Not familiar with that pump.
Does the bypass crack at 50 and then begins to really flow at a higher pressure?
Reset your bypass pressure spring to suit your needs?
Sounds normal for something that bypasses.
The internal pump spring bypasses at a higher pressure I assume, yes?
At what rpm do you see the 100 lbs?
trying to decide what problem you perceive.

[In-Tech]

I believe what Dave is eluding to is that your "test bench" is not real world, meaning the application is not the same as a static fuel injection type application. Many have seen fuel pressure still rise above a bypassing regulator as the pump speed increases volume more than the delta of the bypass.

An engine will "bypass" more oil as the engine rpm increases due to many factors.

[The Radius Kid]

What is the temperature of the oil used in the test?

[Ratsun]

The spring in the oil pump is the strongest one and should not open until 82psi, the bypass will flow 140% of what the pump is capable of making so should never see pressure greater then the bypass pressure, it starts to bypass oil at 50psi and will continue bypassing oil the harder you spin it however the pressure will continue to rise, it bypasses the oil thru the bypass hole and also spews oil out the end of the pump where the welch plug would normally be

[Ratsun]

Here is a link to the pump
http://www.schumannoilpumps.com/Ford-Oi ... s_8273.prt

[turdwilly]

I put the Schuman 351W HV pump in the 427 I just finished up, hasn't been on the dyno yet so no feedback to give you on it, but I used a Schuman 3/4" inlet standard volume pump in the SBC I did a few years ago.

I used the standard spring that came in the pump as delivered (came with 2 additional springs iirc) & on the dyno with 10w30 conventional oil & after a 20 minute warm up, shut down & run the valves, it held about 60 psi on the first pull. On the last of several subsequent pulls, it held about 54 psi at max rpm of 7200. I've never seen what the pressures are in the vehicle, but it has been running for a few years now with no issues. This is an OEM GM 400 block with .0025" on mains & rods, solid roller with no restrictors & .0013-.0015" lifter bore clearance.

[Zmechanic]

Are you simulating the flow that would normally be coming out of it too? If you are asking the bypass to dump the entire volume of oil the pump can displace, it will be far less effective.