On the other forum it was brought up in discussion of a failed FE, an exact quote:
"It had TWO huge holes in the oil system, but still had plenty of pressure."
Here's my take and it relates to the discussion here about accumulators and how much oil an FEs oil system circulates and the pumps pumping capability.
The FE oil pump goes into bypass by pressure depending on the model at 60-80 psi, unlike a filter that goes into bypass mode by differential pressure (psid) through the filter, of only a measly 4-5 psid. FoMoCo claimed 24GPM @ 4,000rpm@70-80psi in the Muscle Parts Catalog for a 427 pump. I can only assume the referenced admittedly "worn out engines" oil pump was trying it's best to pass an unheard of 20+ GPM. No standard FL1 size'd spin-on oil filter can filter 20+GPM. My money's on the filter being faced with 20+GPM goes into bypass by design at 4-5 psid, but still the filter is faced with 20+GPM flow because the oil pump does not bypass until the aforementioned 60-80 psi is attained, this is still a shit-load of gross flow even with the addition of the filters internal bypass valve opened. (a _?_%-through filter media and a _? _% through the bypass valve). Net result with the bypass open that 20+GPM the pumps sending is to much for the filter to both flow through it's filter media & flow through it's bypass circuit. Differential pressure through both the filter and filter media is way beyond design capacity. What does 60-80psid going through a filter do other then indicate many gallons are trying to pass through the filter?........... It overwhelms the filter media, it overwhelms the bypass circuit, it overwhelms the medias pleats, it overwhelms the metal center tube and essentially crushes the internals like a trash compactor all by pressure differential. At some point as the filters guts are starting to fail to Dp there is a critical reaction, the filter media's pleats are known to "pinch" by the pressure differential this act further drastically reduces flow capacity.
This brought up a very interesting point. IF you build your engine loose and/or the bearing clearances are all worn out. Then by the "book" (Muscle Parts Catalog) the oil pump is capable of literally shoving many times the normal volumes of flow through the filter.
When you see guys say their oil accumulators with 2 quarts of usable oil will keep their engine going for 10-15 seconds w/o a pump. Start thinking about over ten times normal flow rates trying to go through the filter.
Normally your properly clearance'd motor is what controls the bypass in the oil pump, if your motor is missing or loose as a goose the oil pump does not know it's only the filter that's building pressure against the pumps bypass valve.
You can even take it further, if you simply screw on an oil filter without prefilling it with oil, theoretically because you are dealing with a positive displacement pump and fluids you have a situation for a second where there is nothing behind the filters media but air, just like jamming open a gate valve at start up, an almost instantaneous slug of oil crashes into the filter media with little support behind it. The moral is pre-fil your filters before you screw them on.
