Ford Windsor 427 SB excessive oil pressure

[eschaider]

Although a restriction would increase oil pressure, as Bob has suggested, it is improbable but not impossible to have that occur in a brand-new crate engine from Ford. It is far more likely that the spring pressure on the oil pressure relief is set too high or the relief valve is jammed in the oil pump.

If the oil pressure relief is not at fault, the only other possible explanation (other than a stiff spring) is, as Bob has already suggested, a blockage in your internal oil galleys. Bob's point about wasted energy is spot on; however, it is usually indiscernible from a driver's perspective if it only makes a difference between 550 RWHP and 545 RWHP.

If you do have an oil galley blockage somewhere in the lubrication system, it will become apparent in short order. The engine parts that are being starved for lubrication frequently exit the block at high velocity, leaving an unmistakable exit path visible.

The issue about the ability to shear off a roll pin is real. Solid dowel pins are pretty robust and unlikely to break. Roll pins, on the other hand, are more fragile and susceptible to damage. If this is a concern, the easy fix is replacing the roll pin with a solid dowel pin. McMaster-Carr will be your friend.

It is worthwhile remembering that high-volume oil pumps will automatically operate at a higher pressure than their lower-volume kindred unless the additional volume is bled off the high-volume pump output through the oil pressure relief — and then you have a high-volume pump performing as if it were a low volume pump!

This begs the obvious question, 'Why did you bother to use a high-volume pump in the first place?'

My personal opinion is your oil pressure is probably just right for a high-volume pump or a lower-volume pump with a zesty pressure relief spring. Your oil pan may need some increased capacity, depending on how big it currently is.

[Davidless]

Thanks for all the info

The Ford long block I bought comes with a high volume pump, nothing I changed.
The engine will be set up with an external oil filter and the supplied filter is a high volume racing filter and the pan holds 9 quarts.

Today I spun the pump with a drill and could get it up around 85 psi.

When using the test stand at idle, warm oil, gage read 80 psi and fluctuated when revving the engine.

Not sure I understand about reducing the bypass spring force, in that case what’s the sense of using a high volume pump?

I find it hard to believe that I have the only long block from Ford that has this problem. Based on my serial number they should be able to see if there were any problems similar to mine.

Guess I will wait and see what the engineers at Ford say about it, after all they have to give me a 24 month warranty, just don’t want to remove the engine from my car if this isn’t right to begin with.

Thanks again for the reply’s.

David

[bobcowan]

Originally Posted by Davidless

Thanks for all the info

Not sure I understand about reducing the bypass spring force, in that case what’s the sense of using a high volume pump?

David

Do not equate pressure with volume.

[patrickt]

There are times when you want a high volume pump. In contrast to your small block, my stroked flat tappet FE has .003 main clearances and .0028 rod clearances. It also has a remote filter and an oil cooler. It runs 15w40 oil and my hot idle pressure is 15psi, sometimes less. This is when idling at 650 and my oil pressure comes up instantly with revs and generally will be in the mid 40's at 2000 RPM when really hot. The lifter galleries are plugged (solid cam) and I have .060 restrictors up top in the heads. And I run a Melling high volume pump.

[eschaider]

Originally Posted by bobcowan

Do not equate pressure with volume.

Pressure and flow rate (volume) are linked at the hip, although they do not have a first-order relationship. The relationship between pressure and flow is a second-order relationship.

Flow increases as the square of pressure. To double the flow through an orifice, you will need to raise the pressure of the fluid pre-orifice by a factor of four (2 squared).

It is not just simplistic to say they are not related, it is wrong. They are linked at the hip.

[eschaider]

From post #5

Originally Posted by eschaider

... My personal opinion is your oil pressure is probably just right for a high-volume pump or a lower-volume pump with a zesty pressure relief spring. Your oil pan may need some increased capacity, depending on how big it currently is.