dnewton3
Staff member
Originally Posted By: circuitsmith
Originally Posted By: dnewton3
However, the LOCATION of the filter (side of the block, under the block, high above the block) will alter the attempt of oil to drain back. This may or may not make an ADBV moot.
With the filter mounted high there is still gravitational effect in the passage leading down from the filter to the pump/sump.
So maybe ADBV is still needed even with the filter high.
I disagree, but I'll explain why.
First, think of how a "normal" filter application sits and performs: traditionally the filter is low on the block and the ADBV is a check-valve of sorts. It stops flow from escaping the filter in the reverse direction. Once shut down, gravity will force the fluid to put pressure into the center tube, thereby trying to push through the media, and stops at the ADBV (generally, as this is it's purpose in life). The check-valve effect holds the oil in the circuit because it is stopping the lube from wanting to leave the filter through the outer hole in the baseplate. In short, the ADBV stops oil from reversing its direction through the filter.
In a high placement situation, typically the filter is inverted and the baseplate is lower point (think 4.0L V-6 Tacoma with dome end up). The filter is very high relative to the engine; at or near the head level. There is very little pressure from the "system" that exists on the upstream side as the pump is shut down. The pressure-fed side of the filter in normal ops is the outer ring of inlet holes, and feeds lube through the media and into the engine via the center tube. Once the engine stops, the pressure feeding into the outer holes stops, but ... there is nothing to stop the oil from continuing to drain through the media, and through the center tube. The ADBV is "upstream" in this sense, and there is nothing in the filter to stop oil from draining in its "normal" direction. Because the pull of gravity is acting on oil in the "normal" direction, the ADBV cannot stop this from happening. Now - it is entirely possible that some other check-valve exists in the engine itself, downstream of the filter to stop this; something could be in place with a low pressure holding point that would stop drain-down with no pump pressure, but was easily overcome with just a few PSI? I have no idea if this exists in the system, but conceptually it could. However, it is not the FILTER ADBV that would be achieving this. In the high-placement, inverted orientation, the ADBV does little-to-nothing because the oil is draining in its "normal" direction and not against the ADBV.
It is possible that in a high-placement, base-plate-up orientation, the filter could hold some oil, but that would be simply because the filter is a "cup" of sorts, and regardless of the ADBV presence, some oil would stay in the "can" with graviting pulling it towards the dome end. However, this is not a typical mounting scenario in most engine apps.
ADBVs don't do much, if anything, when the filter is high, dome end up, because the ADBV is not affecting the "normal" flow direction of lube. It generally will only stop reverse flow.
If you see it differently, please explain.
Originally Posted By: dnewton3
However, the LOCATION of the filter (side of the block, under the block, high above the block) will alter the attempt of oil to drain back. This may or may not make an ADBV moot.
With the filter mounted high there is still gravitational effect in the passage leading down from the filter to the pump/sump.
So maybe ADBV is still needed even with the filter high.
I disagree, but I'll explain why.
First, think of how a "normal" filter application sits and performs: traditionally the filter is low on the block and the ADBV is a check-valve of sorts. It stops flow from escaping the filter in the reverse direction. Once shut down, gravity will force the fluid to put pressure into the center tube, thereby trying to push through the media, and stops at the ADBV (generally, as this is it's purpose in life). The check-valve effect holds the oil in the circuit because it is stopping the lube from wanting to leave the filter through the outer hole in the baseplate. In short, the ADBV stops oil from reversing its direction through the filter.
In a high placement situation, typically the filter is inverted and the baseplate is lower point (think 4.0L V-6 Tacoma with dome end up). The filter is very high relative to the engine; at or near the head level. There is very little pressure from the "system" that exists on the upstream side as the pump is shut down. The pressure-fed side of the filter in normal ops is the outer ring of inlet holes, and feeds lube through the media and into the engine via the center tube. Once the engine stops, the pressure feeding into the outer holes stops, but ... there is nothing to stop the oil from continuing to drain through the media, and through the center tube. The ADBV is "upstream" in this sense, and there is nothing in the filter to stop oil from draining in its "normal" direction. Because the pull of gravity is acting on oil in the "normal" direction, the ADBV cannot stop this from happening. Now - it is entirely possible that some other check-valve exists in the engine itself, downstream of the filter to stop this; something could be in place with a low pressure holding point that would stop drain-down with no pump pressure, but was easily overcome with just a few PSI? I have no idea if this exists in the system, but conceptually it could. However, it is not the FILTER ADBV that would be achieving this. In the high-placement, inverted orientation, the ADBV does little-to-nothing because the oil is draining in its "normal" direction and not against the ADBV.
It is possible that in a high-placement, base-plate-up orientation, the filter could hold some oil, but that would be simply because the filter is a "cup" of sorts, and regardless of the ADBV presence, some oil would stay in the "can" with graviting pulling it towards the dome end. However, this is not a typical mounting scenario in most engine apps.
ADBVs don't do much, if anything, when the filter is high, dome end up, because the ADBV is not affecting the "normal" flow direction of lube. It generally will only stop reverse flow.
If you see it differently, please explain.
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