Gen 1 SBC oil filter bypass

[turbo camino]

This filter bypass can't cause higher pressure than what the pump pressure relief allows, even if the filter is collapsed and completely blocked.

[RT Machine]

This filter bypass can't cause higher pressure than what the pump pressure relief allows, even if the filter is collapsed and completely blocked.

Exactly, and this valve is really a pressure differential valve , if you have had any hydraulics experience, you will know this, when the oil is cold and has much higher viscosity, it takes more pressure to push it through the filter media, if this pressure exceeds the pressure acting on the back side of the bypass valve by about 12 psi [ or whatever the spring is set at] , then the valve will open to enable enough correct oil flow to the oil galleries, its a safety device to prevent restriction to flow.

[68rs406]

As I said in my post, in my case it was the pump bypass that was the issue, allowing elevated pressure. Just using it as an example of a burst and failed filter.

[Walter R. Malik]

Any benefits to plugging this on a street engine with a stock roller 350 block?
Obviously warm up would have to be done properly every time, and routine maintenance would have to be consistent with filter changes.

Hate the idea of oil bypassing the filter at all, even a remote mounted setup with a couple filters plumbed in parallel. Good idea or bad?

On a normally driven street engine you would want some kind of by-pass because dirty oil is better than very little oil in a nearly plugged filter or cold oil situation; a lot of builders simply use a stronger or double spring in the by-pass valve for a regular street, high performance engine.
In a high performance engine where the engine is warmed first before using it and the oil is most always clean, then plugging that so there is no by-pass oil at all can be a good thing.

[68rs406]

On a normally driven street engine you would want some kind of by-pass because dirty oil is better than very little oil in a nearly plugged filter or cold oil situation; a lot of builders simply use a stronger or double spring in the by-pass valve for a regular street, high performance engine.
In a high performance engine where the engine is warmed first before using it and the oil is most always clean, then plugging that so there is no by-pass oil at all can be a good thing.

That was kind of the rationale I went with when deciding to use no filter bypass on mine, this motor rarely sees cold temps and is warmed up sufficiently before driving, and the oil is regularly changed. In anything but a situation like that I would just leave the factory system in place.

[gmrocket]

This filter bypass can't cause higher pressure than what the pump pressure relief allows, even if the filter is collapsed and completely blocked.

Exactly, and this valve is really a pressure differential valve , if you have had any hydraulics experience, you will know this, when the oil is cold and has much higher viscosity, it takes more pressure to push it through the filter media, if this pressure exceeds the pressure acting on the back side of the bypass valve by about 12 psi [ or whatever the spring is set at] , then the valve will open to enable enough correct oil flow to the oil galleries, its a safety device to prevent restriction to flow.

Right, it’s a differential sensing bypass.

If the pressure drop across the filter element is higher than the bypass spring setting, it will open and allow oil to bypass the filter media.

It may also bypass some oil if it’s cold and rpm is high even though the pump is also relieving oil within the oil pumps pressure relief

Most filters have their own internal bypass,, some HP filters do not have a built in bypass, or they also have an extra fine screen over the bypass to catch debris if it opens..like the fram HP2’s

I block it for both those reasons

[gmrocket]

I don't want to start a war, but why would you want to block the pressure relief valve? I have seen it done a bunch on SBC, and BBC engines ? I always put it back to a pressure relief valve when I work on one. I agree all the oil has to go through the filter when you block it, but on cold startup, for example, especially if you run thick oil, you run a very good risk of starving the bearings until you make some heat to thin the oil. I am sure the engineers that designed the relief would have eliminated it if it was not needed. If your crankcase is clean and you change the oil, why would you worry about filtering 100% of the time? Just to try it cut a filter apart and pour cold oil over the filter medium and watch how much runs through the paper, not much.

Your not understandIng what it is ,, it’s not a pressure relief.

The oil pump is where your pressure relief is.

You can’t starve your bearings if your gauge is showing pressure which has nothing to do with the bypass valve

The bypass was engineered into the oil system to allow oil flow past the filter if the filter was not changed or plugged , in which case the filters internal bypass would open, if it has one

[77cruiser]

Oil pressure is measured after the gauge.